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Lecture notes, cheat sheets
General and clinical immunology. Cheat sheet: briefly, the most important
Directory / Lecture notes, cheat sheets Table of contents
1. Immunity. Phagocytosis Immunity (from Latin immunitas - "getting rid of", "liberation from something") is the body's immunity to various infectious agents, as well as their metabolic products, substances and tissues that have alien antigenic properties (for example, animal and vegetable poisons origin). Once having been ill, our body remembers the causative agent of the disease, so the next time the disease proceeds faster and without complications. But often after long-term illnesses, surgical interventions, under adverse environmental conditions and in a state of stress, the immune system can malfunction. Reduced immunity is manifested by frequent and prolonged colds, chronic infectious diseases (tonsillitis, furunculosis, sinusitis, intestinal infections), constant fever, etc. If we summarize all of the above, then we can say that immunity is a way to protect the body from living bodies and substances that carry signs of genetically alien information. The most ancient and stable mechanism of tissue interaction with any external damaging environmental factors (antigens) is phagocytosis. Phagocytosis in the body is carried out by special cells - macrophages, microphages and monocytes (precursor cells of macrophages). This is a complex multi-stage process of capturing and destroying all micro-objects that are foreign to them in the tissues, without touching their own tissues and cells. Phagocytes, moving in the intercellular fluid of the tissue, upon meeting with the antigen, capture it and digest it before it comes into contact with the cell. This defense mechanism was discovered by I. M. Mechnikov in 1883 and was the basis of his theory of phagocytic defense of the body against pathogenic microbes. Wide participation of macrophages in various immunological processes has been established. In addition to protective reactions against various infections, macrophages are involved in antitumor immunity, antigen recognition, regulation of immune processes and immune surveillance, in the recognition and destruction of single altered cells of their own body, including tumor cells, in the regeneration of various tissues and in inflammatory reactions. Macrophages also produce various substances that have anti-antigenic effects. Phagocytosis includes several stages: 1) directed movement of the phagocyte towards an object foreign to the tissue; 2) attachment of the phagocyte to it; 3) recognition of a microbe or antigen; 4) its absorption by a phagocyte cell (actual phagocytosis); 5) killing the microbe with the help of enzymes secreted by the cell; 6) digestion of the microbe. But in some cases, the phagocyte cannot kill certain types of microorganisms, which are even able to multiply in it. That is why phagocytosis cannot always protect the body from damage. 2. Immunity The inflammatory process is a local compensatory mechanism that ensures the restoration of a damaged tissue area that has been changed as a result of interaction with a damaging factor of any nature. In the process of evolution, a specific defense system appeared, which, unlike local defense during phagocytosis, operates at the level of the whole organism. This is an immune system aimed at protecting the body from damaging factors of biological origin. The immune system protects the life support of the whole organism, is a highly specialized system that turns on when local non-specific defense mechanisms have exhausted their capabilities. With the help of the immune system, the reactivity of the organism to certain types of microorganisms is formed and fixed genetically, for interaction with which it is not adapted, and the absence of a reaction of tissues and organs to other species. There are specific and individual forms of immunity. Both forms can be absolute, when the organism and the microbe do not interact directly under any conditions (for example, a person does not get sick with canine distemper), or relative, when the interaction between them can occur under certain conditions that weaken the body's immunity: hypothermia, hunger, overload, and etc. The function of the immune system is to compensate for the insufficiency of nonspecific forms of body defense against antigens in cases where phagocytes cannot destroy the antigen if it has specific defense mechanisms. Therefore, the immune system is characterized by great complexity, duplication of the functions of individual elements, includes cellular and humoral elements designed to accurately identify and then destroy microbes and their metabolic products. The system is self-regulating, reacting not only to the number of microbes, including successively its elements, increasing the sensitivity of non-specific levels of the defense reaction and stopping the immune reaction at the right time. Protein is the carrier of life, maintaining the purity of its protein structure is the duty of a living system. This defense, raised to the highest level in the living organism, includes two types of protective forces. On the one hand, there is the so-called innate immunity, which is of a non-specific nature, i.e., directed in general against any foreign protein. It is known that from the huge army of microbes that constantly enter our body, only an insignificant part manages to cause a particular disease. On the other hand, there is acquired immunity - a striking protective mechanism that occurs during the life of a given organism and is of a specific nature, that is, directed at one specific foreign protein. Immunity, which arose after the transfer of a certain disease, is called acquired. Specific immunity is provided by immune mechanisms and has a humoral and cellular basis. Foreign particles-antigens can settle in the human body, penetrating into it through the skin, nose, mouth, eyes, ears. Fortunately, most of these "enemies" die when they try to get inside the body. 3. Organs of the immune system The organs of the immune system are the bone marrow, thymus, spleen, appendix, lymph nodes, lymphoid tissue diffusely scattered in the mucous base of the internal organs, and numerous lymphocytes that are found in the blood, lymph, organs and tissues. In the bone marrow and thymus, lymphocytes differentiate from stem cells. They belong to the central organs of the immune system. The remaining organs are peripheral organs of the immune system, where lymphocytes are evicted from the central organs. The total weight of all organs representing the immune system of an adult is not more than 1 kg. Central to the immune system are lymphocytes, white blood cells whose function was a mystery until the 1960s. Lymphocytes normally make up about a quarter of all leukocytes. The body of an adult contains 1 trillion lymphocytes with a total mass of about 1,5 kg. Lymphocytes are produced in the bone marrow. One of the important organs of the immune system is the thymus gland, or thymus. It is a small organ located behind the breastbone. The thymus is small. It reaches its greatest value - approximately 25 g - during puberty, and by the age of 60 it significantly decreases and weighs only 6 g. The thymus is literally filled with lymphocytes that come here from the bone marrow. Such lymphocytes are called thymus-dependent, or T-lymphocytes. The task of T-lymphocytes is to recognize the "foreign" in the body, to detect a gene reaction. Another type of lymphocytes is also formed in the bone marrow, but then it does not get into the thymus, but into another organ. So far, this organ has not been found in humans and mammals. It is found in birds - it is an accumulation of lymphoid tissue located near the large intestine. By the name of the researcher who discovered this formation, it is called the bursa of Fabricius (from Latin bursa- "bag"). If the bursa of Fabricius is removed from the chickens, then they stop producing antibodies. This experience shows that another type of lymphocytes, which produces antibodies, is "learning immunological literacy" here. Such lymphocytes were called B lymphocytes (from the word "bursa"). Although a similar organ has not yet been found in humans, the name of the corresponding type of lymphocytes has taken root - these are B-lymphocytes. T-lymphocytes and B-lymphocytes, as well as macrophages and granulocytes (neutrophils, eosinophils and basophils) are all the main cells of the immune system. In addition to lymphocytes, the body has large cells - macrophages located in some tissues. They capture and digest foreign microorganisms. Leukocytes, in addition to invading foreign agents, also destroy malfunctioning, damaged cells that can degenerate into cancerous ones. They produce antibodies that fight specific bacteria and viruses. The circulating lymph picks up toxins and waste products from the tissues and blood and transports them to the kidneys, skin and lungs for removal from the body. The liver and kidneys have the ability to filter toxins and waste products from the blood. 4. B-lymphocytes. T-lymphocytes and macrophages In order for the functioning of the immune system to be normal, a certain ratio between all types of cells must be observed. Any violation of this ratio leads to pathology. This is the most general information about the organs of the immune system. They should be considered in more detail. The state of immunity is associated mainly with the coordinated activity of three types of leukocytes: B-lymphocytes, T-lymphocytes and macrophages. Initially, the formation of them or their precursors (stem cells) occurs in the red bone marrow, then they migrate to the lymphoid organs. There is a peculiar hierarchy of organs of the immune system. They are divided into primary (where lymphocytes are formed) and secondary (where they function). All these organs are connected to each other and to other tissues of the body with the help of blood lymphatic vessels, through which leukocytes move. The primary organs are the thymus (thymus gland) and bursa (in birds), as well as the red bone marrow (possibly the appendix) in humans: hence the T- and B-lymphocytes, respectively. "Training" is aimed at acquiring the ability to differentiate one's own from another's (recognize antigens). To be recognized, body cells synthesize special proteins. Secondary lymphoid organs include the spleen, lymph nodes, adenoids, tonsils, appendix, peripheral lymph follicles. These organs, like the immune cells themselves, are scattered throughout the human body to protect the body from antigens. In the secondary lymphoid organs, the development of an immune response to the antigen occurs. An example is a sharp increase in lymph nodes near the affected organ in inflammatory diseases. The lymphoid organs at first glance seem like a small system of the body, but it has been estimated that their total mass is more than 2,5 kg (which, for example, is more than the mass of the liver). In the bone marrow, cells of the immune system are formed from the progenitor stem cell (the ancestor of all blood cells). B-lymphocytes also undergo differentiation there. The transformation of a stem cell into a B-lymphocyte occurs in the bone marrow. The bone marrow is one of the main sites for antibody synthesis. For example, in an adult mouse, up to 80% of the cells that synthesize immunoglobulins are located in the bone marrow. It is possible to restore the immune system in lethally irradiated animals with the help of intravenous injection of bone marrow cells. 5. Thymus. lymph nodes The thymus is located directly behind the sternum. It is formed earlier than other organs of the immune system (already at the 6th week of pregnancy), but by the age of 15 it undergoes a reverse development, in adults it is almost completely replaced by fatty tissue. Penetrating from the bone marrow into the thymus, under the influence of hormones, the stem cell first turns into the so-called thymocyte (the cell - the precursor of the T-lymphocyte), and then, penetrating into the spleen or lymph nodes, it turns into a mature, immunologically active T-lymphocyte. Most of the T-lymphocytes become the so-called T-killers (killers). A smaller part performs a regulatory function: T-helpers (helpers) enhance immunological reactivity, T-suppressors (suppressors), on the contrary, reduce it. Unlike B-lymphocytes, T-lymphocytes (mainly T-helpers), with the help of their receptors, are able to recognize not just someone else's, but also their own, that is, a foreign antigen should be presented most often by macrophages in combination with the body's own proteins. In the thymus, along with the formation of T-lymphocytes, thymosin and thymopoietin are produced - hormones that ensure the differentiation of T-lymphocytes and play a certain role in cellular immune responses. Lymph nodes are peripheral organs of the immune system that are located along the course of the lymphatic vessels. The main functions are the retention and prevention of the spread of antigens, which is carried out by T-lymphocytes and B-lymphocytes. They are a kind of filter for microorganisms carried by the lymph. Microorganisms pass through the skin or mucous membranes, enter the lymphatic vessels. Through them, they penetrate into the lymph nodes, where they linger and are destroyed. Functions of the lymph nodes: 1) barrier - they are the first to react to contact with a damaging agent; 2) filtration - they delay microbes, foreign particles, tumor cells penetrating with lymph current; 3) immune - associated with the production of immunoglobulins and lymphocytes in the lymph nodes; 4) synthetic - the synthesis of a special leukocyte factor, which stimulates the reproduction of blood cells; 5) exchange - lymph nodes are involved in the metabolism of fats, proteins, carbohydrates and vitamins. 6. Spleen. lymphoid tissue. excretory system The spleen has a structure similar to that of the thymus gland. In the spleen, hormone-like substances are formed that are involved in the regulation of macrophage activity. In addition, phagocytosis of damaged and old red blood cells occurs here. Functions of the spleen: 1) synthetic - it is in the spleen that the synthesis of immunoglobulins of classes M and J is carried out in response to the entry of an antigen into the blood or lymph. The spleen tissue contains T- and B-lymphocytes; 2) filtration - in the spleen, the destruction and processing of substances alien to the body, damaged blood cells, coloring compounds and foreign proteins occur. Lymphoid tissue Lymphoid tissue is located under the mucous membrane. These include the appendix, lymphoid ring, intestinal lymph follicles, and adenoids. Accumulations of lymphoid tissue in the intestine - Peyer's patches. This lymphoid tissue is a barrier to the penetration of microbes through the mucous membranes. Functions of lymphoid accumulations in the intestines and tonsils: 1) recognition - the total surface area of the tonsils in children is very large (almost 200 cm2). On this area there is a constant interaction of antigens and cells of the immune system. It is from here that information about a foreign agent follows to the central organs of immunity: thymus and bone marrow; 2) protective - on the mucous membrane of the tonsils and Peyer's patches in the intestine, in the appendix there are T-lymphocytes and B-lymphocytes, lysozyme and other substances that provide protection. Excretory system The set of microorganisms that inhabit the skin and mucous membranes of a healthy person is a normal microflora. These microbes have the ability to resist the defense mechanisms of the body itself, but they are not able to penetrate tissues. The normal intestinal microflora has a great influence on the intensity of the immune response in the digestive organs. Normal microflora inhibits the development of pathogenic microflora. The internal environment of our body is delimited from the outside world by the skin and mucous membranes. They are the mechanical barrier. In the epithelial tissue (it is located in the skin and mucous membranes), the cells are very strongly interconnected by intercellular contacts. The lacrimal, salivary, gastric, intestinal and other glands, whose secrets are secreted on the surface of the mucous membranes, intensively fight microbes. First, they simply wash them off. Secondly, some fluids secreted by the internal glands have a pH that damages or destroys bacteria (for example, gastric juice). Thirdly, the salivary and lacrimal fluids contain the enzyme lysozyme, which directly destroys bacteria. 7. Cells of the immune system The direct executors of immune reactions are leukocytes. Their purpose is to recognize foreign substances and microorganisms, to fight them, and to record information about them. There are the following types of leukocytes: 1) lymphocytes (T-killers, T-helpers, T-suppressors, B-lymphocytes); 2) neutrophils (stab and segmented); 3) eosinophils; 4) basophils. Lymphocytes are the main figures in immunological surveillance. In the bone marrow, the precursors of lymphocytes are divided into two major branches. One of them (mammals) ends its development in the bone marrow, and in birds - in a specialized lymphoid organ - the bursa (bag). These are B-lymphocytes. After B-lymphocytes leave the bone marrow, they circulate in the bloodstream for a short time, and then they are introduced into peripheral organs. They seem to be in a hurry to fulfill their mission, since the life span of these lymphocytes is short - only 7-10 days. A variety of B-lymphocytes is formed already during fetal development, and each of them is directed against a specific antigen. Another part of the lymphocytes from the bone marrow migrates to the thymus, the central organ of the immune system. This branch is T-lymphocytes. After completion of development in the thymus, some of the mature T-lymphocytes continue to be in the medulla, and some leave it. A significant part of T-lymphocytes become T-killers, a smaller part performs a regulatory function: T-helpers increase immunological reactivity, and T-suppressors, on the contrary, weaken it. Helpers are able to recognize the antigen and activate the corresponding B-lymphocyte (directly upon contact or at a distance with the help of special substances - lymphokines). The most well-known lymphokine is interferon, which is used in medicine in the treatment of viral diseases (for example, influenza), but it is effective only at the initial stage of the onset of the disease. Suppressors have the ability to turn off the immune response, which is very important: if the immune system is not suppressed after neutralizing the antigen, the components of the immune system will destroy the body's own healthy cells, which will lead to the development of autoimmune diseases. Killers are the main link of cellular immunity, as they recognize antigens and effectively affect them. Killers act against cells that are affected by viral infections, as well as tumor, mutated, aging cells of the body. 8. Neutrophils. Basophils. Eosinophils. Macrophages Neutrophils, basophils and eosinophils are types of white blood cells. They got their names for the ability to perceive coloring matter in different ways. Eosinophils react mainly to acidic dyes (Congo red, eosin) and are pink-orange in blood smears; basophils are alkaline (hematoxylin, methyl blue), so they look blue-violet in smears; neutrophils perceive both of them, therefore they stain with a gray-violet color. The nuclei of mature neutrophils are segmented, that is, they have constrictions (therefore they are called segmented), the nuclei of immature cells are called stab. One of the names of neutrophils (microphagocytes) indicates their ability to phagocytize microorganisms, but in smaller quantities than macrophages do. Neutrophils protect against the penetration of bacteria, fungi and protozoa into the body. These cells eliminate dead tissue cells, remove old red blood cells and clean the wound surface. When evaluating a detailed blood test, a sign of an inflammatory process is a shift in the leukocyte formula to the left with an increase in the number of neutrophils. Eosinophils take part in the destruction of parasites (they secrete special enzymes that have a damaging effect on them), in allergic reactions. Macrophages (aka phagocytes) are "eaters" of foreign bodies and the most ancient cells of the immune system. Macrophages are derived from monocytes (a type of white blood cell). They pass the first stages of development in the bone marrow, and then leave it in the form of monocytes (rounded cells) and circulate in the blood for a certain time. From the bloodstream, they enter all tissues and organs, where they change their rounded shape to another, with processes. It is in this form that they acquire mobility and are able to stick to any potentially foreign bodies. They recognize some foreign substances and signal them to T-lymphocytes, and those, in turn, to B-lymphocytes. Then B-lymphocytes begin to produce antibodies - immunoglobulins against the agent, which was "reported" by the phagocyte cell and T-lymphocyte. Sedentary macrophages can be found in almost all human tissues and organs, which provides an equivalent response of the immune system to any antigen that enters the body anywhere. Macrophages eliminate not only microorganisms and foreign chemical poisons that enter the body from outside, but also dead cells or toxins produced by their own body (endotoxins). Millions of macrophages surround them, absorb and dissolve them in order to remove them from the body. A decrease in the phagocytic activity of blood cells contributes to the development of a chronic inflammatory process and the emergence of aggression against the body's own tissues (the appearance of autoimmune processes). With the inhibition of phagocytosis, dysfunction of the destruction and excretion of immune complexes from the body is also observed. 9. Substances with immune complexes. Immunoglobulins Immunoglobulins (antibodies) are a protein molecule. They combine with a foreign substance and form an immune complex, circulate in the blood and are located on the surface of the mucous membranes. The main feature of antibodies is the ability to bind a strictly defined antigen. JgM, JgJ, JgA, JgD, JgE. JgM - this type of antibody appears very first upon contact with an antigen (microbe), an increase in their titer in the blood indicates an acute inflammatory process, JgM play an important protective role when bacteria enter the bloodstream in the early stages of infection. JgJ - antibodies of this class appear some time after contact with the antigen. They participate in the fight against microbes - they form complexes with antigens on the surface of a bacterial cell. Subsequently, other plasma proteins (the so-called complement) join them, and the bacterial cell is lysed (its membrane is torn). JgA - are produced by lymphocytes of the mucous membranes in response to local exposure to a foreign agent, thus they protect the mucous membranes from microorganisms and allergens. JgD is the least studied. Researchers suggest that it is involved in the body's autoimmune processes. JgE - antibodies of this class interact with receptors that are located on mast cells and basophils. As a result, histamine and other mediators of allergy are released, resulting in an allergic reaction. Upon repeated contact with the allergen, JgE interaction occurs on the surface of blood cells, which leads to the development of an anaphylactic allergic reaction. In addition to allergic reactions, JgE is involved in antihelminthic immunity. Lysozyme. Lysozyme is present in all body fluids: in tears, saliva, blood serum. This substance is produced by blood cells. Lysozyme is an antibacterial enzyme that can dissolve the shell of the microbe and cause its death. When exposed to bacteria, lysozyme needs the support of another factor of natural immunity - the complement system. Complement. This is a group of protein compounds involved in the chain of immune reactions. Complement can participate in the destruction of bacteria, preparing them for absorption by macrophages. The complement system consists of nine complex biochemical compounds. By changing the concentrations of any of them, one can judge the place of a possible pathology in the link of immunity. Interferons. These substances provide antiviral immunity, increase the resistance of cells to the effects of viruses, thereby preventing their reproduction in cells. These substances are produced mainly by leukocytes and lymphocytes. The result of the action of interferons is the formation of a barrier around the focus of inflammation from cells that are not infected with the virus. Of all the above organs of immunity, only the thymus undergoes reverse development. 10. Interaction of the organism and the environment The immune response begins immediately after the penetration of a foreign agent into the body, but only when passing through the first line of defense of the immune system. Intact mucosal membranes and skin by themselves present significant barriers to pathogens and produce many antimicrobial agents themselves. More specialized defenses include high acidity (pH around 2,0) in the stomach, mucus, and mobile cilia in the bronchial tree. The range of safe environmental influences is limited by the specifics of the species and the characteristics of the individual person, the rate of adaptation of the individual, his specific phenotype, that is, the totality of the properties of the organism that are congenital and acquired during his life. Each person is biologically unique because within certain genotypes, deviations of some specific traits are possible, creating the uniqueness of each organism, and, consequently, the individual rate of its adaptation when interacting with various environmental factors, including the difference in the level of protection of the organism from damaging factors. If the quality of the environment corresponds to the rate of adaptation of the organism, its protective systems ensure the normal reaction of the organism to the interaction. But the conditions in which a person carries out his life activity are changing, in some cases going beyond the limits of the body's adaptation norm. And then, in extreme conditions for the body, adaptive-compensatory mechanisms are activated that ensure the adaptation of the body to increased loads. Protective systems begin to carry out adaptive reactions, the ultimate goals of which are to preserve the body in its integrity, to restore the disturbed balance (homeostasis). A damaging factor, by its action, causes a breakdown of a certain structure of the body: cells, tissues, sometimes an organ. The presence of such a breakdown turns on the mechanism of pathology, causes an adaptive reaction of protective mechanisms. The breakdown of the structure leads to the fact that the damaged element changes its structural connections, adapts, trying to maintain its "duties" in relation to the organ or organism as a whole. But with a large overload (within the limits of the organism's adaptation rate), if it exceeds the element's adaptation rate, the element can be destroyed in such a way that it changes its functions, i.e., it malfunctions. Then a compensatory reaction is carried out on the part of a higher level of the organism, the function of which can be impaired as a result of the dysfunction of its element. The pathology is on the rise. Thus, cell breakdown, if it cannot be compensated by its hyperplasia, will cause a compensatory reaction from the tissue. If tissue cells are destroyed in such a way that the tissue itself is forced to adapt (inflammation), then compensation will come from the healthy tissue, i.e., the organ will turn on. Thus, in turn, higher and higher levels of the body can be included in the compensatory reaction, which ultimately will lead to the pathology of the whole organism - a disease when a person cannot normally carry out his biological and social functions. 11. Specific and non-specific protection systems A disease is not only a biological phenomenon, but also a social one, in contrast to the biological concept of "pathology". According to WHO definition, health is "a state of complete physical, mental and social well-being". In the mechanism of the development of the disease, two levels of the immunological system are distinguished: nonspecific and specific. The founders of immunology (L. Pasteur and I. I. Mechnikov) originally defined immunity as immunity to infectious diseases. Currently, immunology defines immunity as a method of protecting the body from living bodies and substances that bear signs of foreignness. The non-specific defense system is designed to withstand the action of various damaging factors external to the body of any nature. When a disease occurs, the nonspecific system carries out the first, early defense of the body, giving it time to turn on a full-fledged immune response from the specific system. Nonspecific protection includes the activity of all body systems. It forms an inflammatory process, fever, mechanical release of damaging factors with vomiting, coughing, etc., changes in metabolism, activation of enzyme systems, excitation or inhibition of various parts of the nervous system. The specific (immune) system reacts to the penetration of a foreign agent in the following way: upon initial entry, a primary immune response develops, and upon repeated penetration into the body, a secondary one. They have certain differences. In a secondary response to an antigen, immunoglobulin J is immediately produced. The first interaction of an antigen (virus or bacterium) with a lymphocyte causes a reaction called the primary immune response. During it, lymphocytes begin to develop gradually, undergoing differentiation: some of them become memory cells, others are transformed into mature cells that produce antibodies. At the first encounter with an antigen, antibodies of the immunoglobulin class M first appear, then J, and later A. A secondary immune response develops upon repeated contact with the same antigen. The nonspecific defense system includes cellular and humoral elements. Cellular elements of nonspecific protection are the phagocytes described above: macrophages and neutrophilic granulocytes (neutrophils, or macrophages). These are highly specialized cells that differentiate from stem cells produced by the bone marrow. Macrophages constitute a separate mononuclear (single-nuclear) system of phagocytes in the body, which includes bone marrow promonocytes, blood monocytes that differentiate from them, and tissue macrophages. Their feature is active mobility, the ability to adhere and intensively carry out phagocytosis. Monocytes, having matured in the bone marrow, circulate for 1-2 days in the blood, and then penetrate into tissues, where they mature into macrophages and live for 60 or more days. 12. Macrophages. microphages. phagocytes Macrophages contain enzymes for the digestion of phagocytosed substances. These enzymes are contained in vacuoles (vesicles) called lysosomes and are able to break down proteins, fats, carbohydrates and nucleic acids. Macrophages cleanse the human body of particles of inorganic origin, as well as bacteria, viral particles, dying cells, toxins - toxic substances formed during the decay of cells or produced by bacteria. In addition, macrophages secrete some humoral and secretory substances into the blood: complement elements C2, C3, C4, lysozyme, interferon, interleukin-1, prostaglandins, o^-macroglobulin, monokines that regulate the immune response, cytotoxins - poisonous for substance cells. Macrophages have a subtle mechanism for recognizing foreign particles of an antigenic nature. They distinguish and quickly absorb old and newborn erythrocytes, without touching the normal ones. For a long time, the role of "cleaners" was assigned to macrophages, but they are also the first link in a specialized defense system. Macrophages, including the antigen in the cytoplasm, recognize it with the help of enzymes. Substances are released from lysosomes that dissolve the antigen within approximately 30 minutes, after which it is excreted from the body. The antigen is expressed and recognized by macrophages, after which it passes to lymphocytes. Neutrophil granulocytes (neutrophils, or microphages) are also formed in the bone marrow, from where they enter the bloodstream, where they circulate for 6-24 hours. Unlike macrophages, mature microphages receive energy not from respiration, but from glycolysis, like prokaryotes, that is, they become anaerobes, and can carry out their activities in oxygen-free zones, for example, in exudates during inflammation, supplementing the activity of macrophages. Macrophages and microphages on their surface carry receptors for immunoglobulin JgJ and complement element C3, which help the phagocyte in recognizing and attaching the antigen to the surface of its cell. Violation of the activity of phagocytes quite often manifests itself in the form of recurrent purulent-septic diseases, such as chronic pneumonia, pyoderma, osteomyelitis, etc. In a number of infections, various acquisitions of phagocytosis occur. Thus, tuberculosis mycobacteria are not destroyed by phagocytosis. Staphylococcus inhibits its absorption by the phagocyte. Violation of the activity of phagocytes also leads to the development of chronic inflammation and diseases associated with the fact that the material accumulated by macrophages from the decomposition of phagocytized substances cannot be removed from the body due to the deficiency of some phagocyte enzymes. The pathology of phagocytosis may be associated with impaired interaction of phagocytes with other systems of cellular and humoral immunity. Phagocytosis is facilitated by normal antibodies and immunoglobulins, complement, lysozyme, leukins, interferon, and a number of other enzymes and blood secretions that pre-process the antigen, making it more accessible for capture and digestion by the phagocyte. 13. Complement Complement is an enzyme system that consists of 11 blood serum proteins that make up 9 components (from C. to C9) of complement. The complement system stimulates phagocytosis, chemotaxis (attraction or repulsion of cells), the release of pharmacologically active substances (anaphylotoxin, histamine, etc.), enhances the bactericidal properties of blood serum, activates cytolysis (cell breakdown) and, together with phagocytes, takes part in the destruction of microorganisms and antigens . Each component of complement plays a role in the immune response. Thus, complement C1 deficiency causes a decrease in the bactericidal activity of blood plasma and contributes to the frequent development of infectious diseases of the upper respiratory tract, chronic glomerulonephritis, arthritis, otitis media, etc. Complement C3 prepares the antigen for phagocytosis. With its deficiency, the enzymatic and regulatory activity of the complement system is significantly reduced, which leads to more serious consequences than the deficiency of complements C. and C2, up to death. Its modification is deposited on the surface of the bacterial cell, which leads to the formation of holes in the shell of the microbe and its lysis, i.e., dissolution by lysozyme. With hereditary deficiency of the C5 component, there is a violation of the development of the child, dermatitis and diarrhea. Specific arthritis and bleeding disorders are observed in C6 deficiency. Diffuse lesions of the connective tissue occur with a decrease in the concentration of components C2 and C7. Congenital or acquired insufficiency of complement components contributes to the development of various diseases, both as a result of a decrease in the bactericidal properties of the blood, and due to the accumulation of antigens in the blood. In addition to deficiency, activation of complement components also occurs. Thus, activation of C1 leads to Quincke's edema, etc. Complement is actively consumed during thermal burns, when complement deficiency is created, which can determine an unfavorable outcome of thermal injury. Normal antibodies are found in the serum of healthy people who have not previously been ill. Apparently, these antibodies arise during inheritance, or antigens come with food without causing the corresponding disease. The detection of such antibodies indicates the maturity and normal functioning of the immune system. Normal antibodies include, in particular, properdin. It is a high molecular weight protein found in blood serum. Properdin provides bactericidal and virus-neutralizing properties of blood (together with other humoral factors) and activates specialized defense reactions. 14. Lysozyme. Mechanisms of immunity Lysozyme is an enzyme called acetylmuramidase that breaks down the membranes of bacteria and lyses them. It is found in almost all tissues and body fluids. The ability to destroy the cell membranes of bacteria, from which destruction begins, is explained by the fact that lysozyme is found in high concentration in phagocytes and its activity increases during microbial infection. Lysozyme enhances the antibacterial action of antibodies and complement. It is part of saliva, tears, skin secretions as a means of enhancing the body's barrier defenses. Inhibitors (retarders) of viral activity are the first humoral barrier that prevents the contact of the virus with the cell. People with a high content of highly active inhibitors are highly resistant to viral infections, while viral vaccines are ineffective for them. Nonspecific defense mechanisms - cellular and humoral - protect the internal environment of the body from various damaging factors of organic and inorganic nature at the tissue level. They are sufficient to ensure the vital activity of low-organized (invertebrate) animals. The complication of the organism of animals, in particular, has led to the fact that the nonspecific protection of the organism was insufficient. The complication of organization has led to an increase in the number of specialized cells that differ from each other. Against this general background, as a result of a mutation, cells harmful to the body could appear, or similar, but foreign cells could be introduced into the body. Genetic control of cells becomes necessary, and a specialized system for protecting the body from cells that differ from its native, necessary ones appears. The mechanism of immunity, which arose as a means of internal control over the cellular composition of organ tissues, due to its high efficiency, is used by nature against damaging antigen factors: cells and products of their activity. With the help of this mechanism, the reactivity of the organism to certain types of microorganisms, to the interaction with which it is not adapted, and the immunity of cells, tissues and organs to others are formed and fixed genetically. There are specific and individual forms of immunity, which are formed, respectively, in adaptatiogenesis and adaptiomorphosis as manifestations of compensationogenesis and compensationomorphosis. Both forms of immunity can be absolute, when the organism and the microorganism practically do not interact under any conditions, or relative, when the interaction causes a pathological reaction in certain cases, weakening the body's immunity, making it susceptible to the effects of microorganisms that are safe under normal conditions. 15. Specific immunological defense system The task of a specific immunological defense system of the body is to compensate for the insufficiency of nonspecific factors of organic origin - antigens, in particular microorganisms and toxic products of their activity. It begins to act when nonspecific defense mechanisms cannot destroy an antigen that is similar in its characteristics to the cells and humoral elements of the organism itself or provided with its own protection. Therefore, a specific protection system is designed to recognize, neutralize and destroy genetically alien substances of organic origin: infectious bacteria and viruses, organs and tissues transplanted from another organism, which have changed as a result of mutation of the cells of one's own organism. The accuracy of discrimination is very high, up to the level of one gene that differs from the norm. The specific immune system is a collection of specialized lymphoid cells: T-lymphocytes and B-lymphocytes. There are central and peripheral organs of the immune system. The central ones include the bone marrow and thymus, the peripheral ones include the spleen, lymph nodes, lymphoid tissue of the intestines, tonsils and other organs, blood. All cells of the immune system (lymphocytes) are highly specialized, their supplier is the bone marrow, from the stem cells of which all forms of lymphocytes are differentiated, as well as macrophages, microphages, erythrocytes, and blood platelets. The second most important organ of the immune system is the thymus gland. Under the influence of thymus hormones, thymus stem cells differentiate into thymus-dependent cells (or T-lymphocytes): they provide the cellular functions of the immune system. In addition to T-cells, the thymus secretes into the blood humoral substances that promote the maturation of T-lymphocytes in peripheral lymphatic organs (spleen, lymph nodes), and some other substances. The spleen has a structure similar to that of the thymus, but unlike the thymus, the lymphoid tissue of the spleen is involved in humoral-type immune responses. The spleen contains up to 65% of B-lymphocytes, which provide the accumulation of a large number of plasma cells that synthesize antibodies. Lymph nodes contain predominantly T-lymphocytes (up to 65%), and B-lymphocytes, plasma cells (derived from B-lymphocytes) synthesize antibodies when the immune system is just maturing, especially in children of the first years of life. Therefore, the removal of the tonsils (tonsillectomy), produced at an early age, reduces the body's ability to synthesize certain antibodies. Blood belongs to the peripheral tissues of the immune system and contains, in addition to phagocytes, up to 30% of lymphocytes. T-lymphocytes predominate among lymphocytes (50-60%). B-lymphocytes make up 20-30%, about 10% are killers, or "null-lymphocytes" that do not have the properties of Ti B-lymphocytes (D-cells). 16. T-lymphocytes T-lymphocytes form three main subpopulations: 1) T-killers carry out immunological genetic surveillance, destroying mutated cells of their own body, including tumor cells and genetically alien transplant cells. T-killers make up to 10% of T-lymphocytes in peripheral blood. It is T-killers that, by their action, cause rejection of transplanted tissues, but this is also the first line of defense of the body against tumor cells; 2) T-helpers organize an immune response by acting on B-lymphocytes and giving a signal for the synthesis of antibodies against the antigen that has appeared in the body. T-helpers secrete interleukin-2, which acts on B-lymphocytes, and g-interferon. They are in peripheral blood up to 60-70% of the total number of T-lymphocytes; 3) T-suppressors limit the strength of the immune response, control the activity of T-killers, block the activity of T-helpers and B-lymphocytes, suppressing the excessive synthesis of antibodies that can cause an autoimmune reaction, that is, turn against the body's own cells. T-suppressors make up 18-20% of T-lymphocytes in peripheral blood. Excessive activity of T-suppressors can lead to inhibition of the immune response up to its complete suppression. This happens with chronic infections and tumor processes. At the same time, insufficient activity of T-suppressors leads to the development of autoimmune diseases due to the increased activity of T-killers and T-helpers, which are not restrained by T-suppressors. To regulate the immune process, T-suppressors secrete up to 20 different mediators that accelerate or slow down the activity of T- and B-lymphocytes. In addition to the three main types, there are other types of T-lymphocytes, including immunological memory T-lymphocytes, which store and transmit information about the antigen. When they encounter this antigen again, they provide its recognition and the type of immunological response. T-lymphocytes, performing the function of cellular immunity, in addition, synthesize and secrete mediators (lymphokines), which activate or slow down the activity of phagocytes, as well as mediators with cytotoxic and interferon-like actions, facilitating and directing the action of a non-specific system . 17. B-lymphocytes B-lymphocytes differentiate in the bone marrow and group lymphatic follicles and perform the function of humoral immunity. When interacting with antigens, B-lymphocytes change into plasma cells that synthesize antibodies (immunoglobulins). The surface of a B-lymphocyte can contain from 50 to 150 immunoglobulin molecules. As B-lymphocytes mature, they change the class of immunoglobulins they synthesize. Initially synthesizing JgM class immunoglobulins, upon maturation, 10% of B-lymphocytes continue to synthesize JgM, 70% switch to JgJ synthesis, and 20% switch to JgA synthesis. Like T-lymphocytes, B-lymphocytes consist of several subpopulations: 1) B1-lymphocytes - precursors of plasmocytes, synthesizing JgM antibodies without interacting with T-lymphocytes; 2) B2-lymphocytes - precursors of plasmocytes, synthesizing immunoglobulins of all classes in response to interaction with T-helpers. These cells provide humoral immunity to antigens recognized by T helper cells; 3) B3-lymphocytes (K-cells), or B-killers, kill antigen cells coated with antibodies; 4) B-suppressors inhibit the function of T-helpers, and memory B-lymphocytes, preserving and transmitting memory of antigens, stimulate the synthesis of certain immunoglobulins upon re-encounter with an antigen. A feature of B-lymphocytes is that they specialize in specific antigens. When B-lymphocytes react with an antigen encountered for the first time, plasma cells are formed that secrete antibodies specifically against this antigen. A clone of B-lymphocytes is formed, responsible for the reaction with this particular antigen. With a repeated reaction, only B-lymphocytes multiply and synthesize antibodies, or rather, plasma cells directed against this antigen. Other clones of B-lymphocytes do not participate in the reaction. B-lymphocytes are not directly involved in the fight against antigens. Under the influence of stimuli from phagocytes and T-helpers, they are transformed into plasma cells, which synthesize antibodies immunoglobulins that neutralize antigens. 18. Immunoglobulins Immunoglobulins are proteins in the blood serum and other body fluids that act as antibodies that bind to antigens and neutralize them. Currently, 5 classes of human immunoglobulins (JgJ, JgM, JgA, JgD, JgE) are known, which differ significantly in their physicochemical properties and biological functions. Class J immunoglobulins make up about 70% of the total number of immunoglobulins. These include antibodies against antigens of various nature, produced by four subclasses. They mainly perform antibacterial functions and form antibodies against polysaccharides of bacterial membranes, as well as anti-Rhesus antibodies, provide a skin sensitivity reaction and complement fixation. Class M immunoglobulins (about 10%) are the most ancient, synthesized in the early stages of the immune response to most antigens. This class includes antibodies against polysaccharides of microorganisms and viruses, rheumatoid factor, etc. Class D immunoglobulins make up less than 1%. Their role in the body is almost not studied. There is evidence of their increase in certain infectious diseases, osteomyelitis, bronchial asthma, etc. Class E immunoglobulins, or reagins, have an even lower concentration. JgE play the role of a trigger in the deployment of immediate-type allergic reactions. By binding to the complex with the allergen, JgE causes the release of mediators of allergic reactions (histamine, serotonin, etc.) into the body. Class A immunoglobulins make up about 20% of the total number of immunoglobulins. This class includes antibodies against viruses, insulin (in diabetes mellitus), thyroglobulin (in chronic thyroiditis). A feature of this class of immunoglobulins is that they exist in two forms: serum (JgA) and secretory (SJgA). Class A antibodies neutralize viruses, neutralize bacteria, prevent the fixation of microorganisms on the cells of the epithelial surface of the mucous membranes. Summing up, we will draw the following conclusion: a specific system of immunological protection is a multi-level mechanism of the elements of the body that ensures their interaction and complementarity, including, as necessary, components of protection against any interaction of the body with damaging factors, duplicating, in necessary cases, the mechanisms of cellular protection by humoral means, and vice versa . 19. Immune system The immune system that has developed in the process of adaptatiogenesis, which has fixed the genetically specific reactions of the organism to damaging factors, is a flexible system. In the process of adaptiomorphosis, it is corrected, it includes new types of reactions to damaging factors that have reappeared, which the body has not encountered before. In this sense, it plays an adaptive role, combining adaptive reactions, as a result of which the body's structures change under the influence of new environmental factors, and compensatory reactions that preserve the integrity of the body, seeking to reduce the price of adaptation. This price is irreversible adaptive changes, as a result of which the organism, adapting to new conditions of existence, loses the ability to exist under the original conditions. So, a eukaryotic cell, adapted to exist in an oxygen atmosphere, can no longer do without it, although anaerobes can do this. The price of adaptation in this case is the loss of the ability to exist in anaerobic conditions. Thus, the immune system includes a number of components that independently engage in the fight against any foreign factors of organic or inorganic origin: phagocytes, T-killers, B-killers and a whole system of specialized antibodies aimed at a specific enemy. The manifestation of the immune response of a specific immune system is diverse. In the event that a mutated cell of the body acquires properties that are different from the properties of its genetically inherent cells, for example, tumor cells, T-killers infect the cells on their own, without the intervention of other elements of the immune system. B-killers also destroy recognized antigens coated with normal antibodies on their own. A complete immune response occurs against some antigens that first enter the body. Macrophages, phagocytizing such antigens of viral or bacterial origin, cannot completely digest them and throw them away after a while. The antigen that has passed through the phagocyte bears a label indicating its "indigestibility". The phagocyte thus prepares the antigen for "feeding" into the specific immune defense system. It recognizes the antigen and labels it accordingly. In addition, the macrophage simultaneously secretes intelukin-1, which activates T-helpers. T-helper, faced with such a "labeled" antigen, gives a signal to B-lymphocytes about the need for their intervention, secreting interleukin-2, which activates lymphocytes. Thus, the specific immune response provides for various cases of interaction between the antigen and the immune system. It involves a complement that prepares the antigen for phagocytosis, phagocytes that process the antigen and supply it to lymphocytes, T- and B-lymphocytes, immunoglobulins and other components. But, like any complex system, immunity has a drawback. A defect in one of the elements leads to the fact that the entire system may fail. There are diseases associated with immunosuppression, when the body cannot independently counteract the infection. 20. Immune status Violation of the mechanisms of implementation of the immune response leads to various pathologies of immunity that are dangerous to health and life. The most common form of such a pathology is immunological deficiency, or, according to generally accepted international terminology, immunodeficiency states. Let us briefly consider the general patterns of the functioning of the immune system. First, the effectiveness of the immune system is based on the balance of its components. Each component of the immune system largely mimics the functions of the other components. Thus, a defect in a part of the components (or links) of the immune system can often be compensated by other components of the immune system. Therefore, if a person has a defect in any immune component, it is necessary to use drugs that improve cell metabolism as an adjuvant. Secondly, the cells of the immune system carry out their basic functions in an active state. The main stimulus for the activation of all cells of the immune system is the antigen. But there are situations when the antigen acts as a suppressive factor. For example, the phenomenon of the so-called lazy leukocytes, which do not react actively enough to a foreign substrate, is known. Thirdly, the degree of activation of the immune system is related to the level of the totality of its components. In healthy people, the number and intensity of interactions between the components of the immune system are usually minimal. When an inflammatory process occurs during the active work of the immune system, their number increases dramatically. With a favorable outcome (after recovery), the relationship between the components decreases again. The chronic process is characterized by maintaining a high level of the totality of immune components (mostly several times more than in healthy people), which is regarded as a syndrome of immune system tension. This is explained by the fact that under these circumstances, the immune system continues to actively fight the foreign agent, maintaining it at some compensated level, but is not able to completely eliminate it. Thus, the immune status determines in total the individual reactivity of the organism and reflects the boundaries of interaction with the environment, beyond which a normal reaction turns into a pathological one. Any acute disease is not a consequence of the fact that in the human environment there are all kinds of pathogenic bacteria. In the fight against the pathogen, ever higher levels of the body, including vital systems, are included. The body in this case works to the limit. Compensatory reactions can reach such strength that life support systems begin to be affected. The study of the immune status includes: 1) determination of blood group and Rh factor; 2) a general blood test with an expanded leukogram or formula; 3) determination of the amount of immunoglobulins; 4) study of lymphocytes; 5) study of the phagocytic activity of neutrophils. 21. Leukocytes The norm is 3,5-8,8 4 h 109 / l. An increase in the number of leukocytes is leukocytosis, a decrease is leukopenia. Leukocytosis is divided into physiological and pathological. Causes of physiological leukocytosis can be food intake (while the number of leukocytes does not exceed 10-12 x109 / l), physical work, hot and cold baths, pregnancy, childbirth, premenstrual period. For this reason, blood should be taken on an empty stomach and before that, do not engage in heavy physical work. For pregnant women, women in childbirth, children have their own rules. Pathological leukocytosis occurs in infectious diseases (pneumonia, meningitis, general sepsis, etc.), infectious diseases with damage to the cells of the immune system (infectious mononucleosis and infectious lymphocytosis), various inflammatory diseases caused by microorganisms (furunculosis, erysipelas, peritonitis, etc.). d.). But there are also exceptions. For example, some infectious diseases occur with leukopenia (typhoid fever, brucellosis, malaria, rubella, measles, influenza, viral hepatitis in the acute phase). The absence of leukocytosis in the acute phase of an infectious disease is an unfavorable sign, which indicates a weak resistance of the organism. At the heart of inflammatory diseases of non-microbial etiology, the so-called autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, etc.), infarcts of various organs, is non-microbial inflammation (necrosis); extensive burns, large blood loss. Causes of leukopenia: 1) exposure to certain chemicals (for example, benzene); 2) taking certain drugs (butadione, reopirine, sulfonamides, cytostatics, etc.); 3) radiation, x-rays; 4) violation of hematopoiesis; 5) blood diseases (leukemia) - leukopenic and aleukopenic forms; 6) overdose of cytostatics during chemotherapy; 7) metastases of tumors in the bone marrow; 8) diseases of the spleen, lymphogranulomatosis; 9) some endocrine diseases (acromegaly, Cushing's disease and syndrome, some of the infectious diseases mentioned above). 22. Lymphocytes Norm: absolute content - 1,2-3,0 x109 / l, but more often in a clinical blood test, the percentage of lymphocytes is indicated. This figure is 19-37%. There are also lymphocytosis and lymphopenia. Lymphocytosis is found in chronic lymphocytic leukemia, chronic radiation sickness, bronchial asthma, thyrotoxicosis, some infectious diseases (whooping cough, tuberculosis), and removal of the spleen. Anomalies in the development of the lymphoid system, ionizing radiation, autoimmune diseases (systemic lupus erythematosus), endocrine diseases (Cushing's disease, taking hormonal drugs), AIDS lead to lymphopenia. T-lymphocytes Norm: relative content 50-90%, absolute - 0,8-2,5 x 109 / l. The number of T-lymphocytes increases with allergic diseases, during the recovery period, with tuberculosis. A decrease in the content of T-lymphocytes occurs with chronic infections, immunodeficiencies, tumors, stress, trauma, burns, some forms of allergies, heart attack. T-helpers Norm: relative content - 30-50%, absolute - 0,6-1,6x109 / l. The content of T-helpers increases with infections, allergic diseases, autoimmune diseases (rheumatoid arthritis, etc.). A decrease in the content of T-helpers occurs in immunodeficiency states, AIDS, cytomegalovirus infection. B-lymphocytes Norm: relative content - 10-30%, absolute - 0,1-0,9x109 / l. An increased content occurs with infections, autoimmune diseases, allergies, lymphocytic leukemia. A decrease in the number of B-lymphocytes is found in immunodeficiencies, tumors. Phagocytes (neutrophils) Their activity is assessed using methods that determine the proportion of cells capable of forming a phagosome (digestive vesicle) inside themselves. To assess the digestive capacity of neutrophils, the NBT test is used (NBT is a nitrosine tetrazolium dye). The norm of the NST-test is 10-30%. The phagocytic activity of leukocytes increases in acute bacterial infections, decreases in congenital immunodeficiencies, chronic infections, autoimmune diseases, allergies, viral infections, AIDS. The activity of phagocytes, i.e., “devourer” cells, is estimated by the so-called phagocytic number (normally, a cell absorbs 5-10 microbial particles), phagocytic blood capacity, the number of active phagocytes, and the phagocytosis completion index (should be more than 1,0) . 23. Immunoglobulins Jg (antibodies) Immunoglobulin A. Norm: 0,6-4,5 g / l. JgA rises in acute infections, autoimmune diseases (often in the lungs or intestines), nephropathies. A decrease in JgA occurs in chronic diseases (especially the respiratory system and gastrointestinal tract), purulent processes, tuberculosis, tumors, and immunodeficiencies. Immunoglobulin M. Norm: 0,4-2,4 g / l. The content of JgM increases with bronchial asthma, infections (acute and chronic), with exacerbations, autoimmune diseases (especially with rheumatoid arthritis). Decreased Jgl in primary and secondary immunodeficiencies. Immunoglobulin J. Norm: 6,0-20,0 g / l. The amount of JgJ increases in the blood with allergies, autoimmune diseases, past infections. A decrease in the content of JgJ occurs in primary and secondary immunodeficiencies. Immunoglobulin E. Norm: 20-100 g / l. The amount of JgE increases with hereditary allergic reactions, allergic lesions of the respiratory organs with the fungus Aspergillus, helminthic invasion and parasitic infection (giardiasis). A decrease in JgE occurs with chronic infections, taking drugs that inhibit cell division, and congenital immunodeficiency diseases. When examining the immune status, the number of immune complexes (IC) is also determined. The immune complex consists of an antigen, an antibody, and their associated components. The content of IC in the blood serum normally ranges from 30 to 90 IU / ml. The content of immune complexes increases in acute and chronic infections and makes it possible to distinguish these stages from each other, in allergic reactions (and determines the type of these reactions), intoxication of the body (kidney disease, immunoconflict), pregnancy, etc. All of the above norms of immune status indicators may differ slightly in different immunological laboratories. It depends on the diagnostic technique and the reagents used. Normal indicators of the immune status indicate a reliable "shield" of the body and, therefore, that a person has good health. But the immune system, like any other system of the body, can have disorders in any part. In other words, the immune system itself can be "sick". There are so-called immuno-deficiencies. The basis of immunodeficiency states are violations of the genetic code that do not allow the immune system to carry out one or another link of the immune response. Immunodeficiency states can be primary and secondary. In turn, the primary ones are congenital, and the secondary ones are acquired. 24. Congenital immunodeficiencies This pathology is genetically determined. Most often, congenital immunodeficiencies appear in the first months of life. Children very often suffer from infectious diseases, which often occur with complications. There is a working classification of congenital immune deficiency conditions proposed by WHO experts in 1971. According to this classification, primary immunodeficiencies are divided into five large groups. The first group includes diseases that are associated only with a defect in B-cells: Bruton's sex-linked agammaglobulinemia, transient (transient) hypogammaglobulinemia, X-linked immune deficiency and M hyperimmunoglobulinemia, etc. The second group includes diseases of immune deficiency with a defect only in T-cells: thymus hypoplasia (DiGeorge syndrome), episodic lymphocytopenia, etc. The third group is diseases with simultaneous damage to B- and T-cells: immune deficiency with or without hypergammaglobulinemia, immune deficiency with ataxia, telangiectasia (Louis-Barr syndrome), thrombocytopenia and eczema (Wiskott-Aldridge syndrome), thymoma ( thymus tumor), etc. The fourth group includes immunodeficiency states in which B- and T-stem cells are simultaneously affected: immune deficiency with generalized hypoplasia of the hematopoietic system, severe, combined immunodeficiency linked to the X chromosome, etc. The final fifth group includes the states of immune deficiency that are not qualified above. In practice, congenital conditions of immune deficiency are limited to three main groups: 1) defects in phagocytosis; 2) insufficiency of cellular and humoral immunity (T-, B- and stem cells); 3) dysfunction of the complementary system. Defects in phagocytosis constitute a large group of diseases. Here, there are mainly dysfunctions of granulocytes and related cells: chronic idiopathic neutrocytopenia with lymphocytosis (essential benign granulocytopenia, often affecting premature babies), inherited autosomal recessively agranulocytosis, which begins in early infancy and ends with the death of a child from bacterial infections. infections in the first years of his life, dysfunction of granulocytes, degranulation syndrome (congenital dysphagocytosis), congenital hypoplasia of the spleen, etc. Defects in humoral and cellular immunity cause the following conditions: 1) severe combined immune defect syndrome with impaired cellular immunity and antibody formation; 2) thymus hypoplasia (DiGeorge syndrome); 3) absence of purine nucleoside phosphorylase; 4) syndrome of ataxia and telangiectasia; 5) thymoma with immunodeficiency syndrome, etc. 25. Agammaglobulinemia Selective deficiency of JgA This disease is based on an isolated defect of B-lymphocytes that cannot mature into plasma cells, is inherited recessively, is X-linked, and is the first described state of immune deficiency. This disease affects only boys. The body cannot produce all classes of immunoglobulins, and without treatment, children die at an early age from recurrent infections. In many cases, patients develop well until 6-8 months of age. This appears to be due to the transplacental transfer of immunoglobulins from the mother. Pathology manifests itself with the final exhaustion of the received reserves. This is a relatively rare disease - approximately 13 patients per 1 boys. Clinically, the disease is manifested by the fact that boys often suffer from recurrent infections caused by pneumococci, streptococci, and the influenza virus. Less often there are infections caused by meningococci, staphylococci. The infectious process is localized in the paranasal sinuses, middle ear, bronchi, lungs, and in the membranes of the brain. In such patients, the course of viral infections is the same as in healthy children, with the exception of viral hepatitis and enterovirus infections. Affected boys do not have tonsils (tonsillar tissue) and lymph nodes. In a laboratory study, the number of lymphocytes is usually normal. When determining B- and T-lymphocytes, a very pronounced decrease in the number of B-lymphocytes and a normal number of T-lymphocytes are found. Selective deficiency of JgA It is an isolated JgA deficiency with normal or elevated levels of other immunoglobulins. It is the most common immunodeficiency condition, which is found in healthy individuals from 1:300 to 1:3000 cases in various studies. The absence of JgA is quite often combined with chromosomal abnormalities (especially the 18th pair of chromosomes), with developmental defects after intrauterine infections. It is likely that in the 18th pair of chromosomes there is a gene that regulates the synthesis of JgA. The clinical manifestations of this pathology are very diverse: from the complete absence of symptoms to severe illness. The most frequently observed pulmonary infections, diarrhea and autoimmune diseases. The defeat of the digestive and respiratory systems is explained by the absence of the secretory component of JgA. Patients with selective JgA deficiency have an increased tendency to form immune complexes. This explains the often observed selective deficiency of JgA in systemic lupus erythematosus, rheumatoid arthritis, pernicious anemia, thyroiditis, diabetes mellitus, Addison's disease, chronic active hepatitis, etc. 26. Immune deficiency of JgM Transient gammaglobulinemia The disease is genetically determined, inherited recessively, transmitted with the X chromosome and is characterized by an increase in JgM with normal or reduced levels of JgJ and JgA in blood plasma. There is another name for this immunodeficiency - dysgammaglobulinemia I and II. Clinical signs appear in the first or second year of life in the form of severe, frequently recurring bacterial infections. Purulent infections are the most frequent: skin abscesses, ulcerations of the oral cavity, otitis media, tonsillitis, lymphadenitis, sinusitis, and respiratory tract lesions. Sometimes the disease generalizes and leads to sepsis. Patients with hyperimmunoglobulinemia M often develop autoimmune diseases. The disease is complicated by neutropenia. Transient hypogammaglobulinemia It is known that only antibodies of the JgJ class pass into the placenta. Having penetrated into the fetus in this form, they are again resynthesized into whole JgJ molecules. As a result, in some newborns, the level of JgJ in the blood may be higher than their level in the mother's blood. Maternal antibodies and infant immunoglobulins are usually metabolized after birth, and JgJ levels begin to decline, reaching their minimum between the 3rd and 6th months of life. The JgM system is activated first, as a result of which, a few days after birth, antibodies of this system are detected in the blood. JgJ react more slowly - within a few weeks, and the concentration of JgA reaches their values in adults only after a few months or even years. Secretory JgA is formed in large quantities in a much shorter time. Activation of the own synthesis of immunoglobulins in the fetus is possible with intensive antigenic stimulation. In this case, the JgM system reacts especially quickly and intensively. Therefore, the detection of an increased level of JgM in the blood serum of newborns indicates the presence of intrauterine infection. In infants, there are several types of transient (transient) hypogammaglobulinemia. The most common physiological hypogammaglobulinemia, which usually disappears by the end of the first six months of a child's life. Pathological hypogammaglobulinemia occurs in preterm infants, as transfer of immunoglobulins across the placenta begins by the end of the 20th week and continues until birth. There is a clear relationship between gestational age and immunoglobulin levels. Their low value is affected by the limited possibility of immunoglobulin synthesis in premature infants. Also, pathological hypogammaglobulinemia in infants can be observed with maternal hypogammaglobulinemia, which is compensated under the influence of their own products. And, finally, pathological transient hypogammaglobulinemia occurs in cases of delayed maturation of the immunoglobulin production system. This may be due to lack of contact with antigens, as well as unknown reasons. The diagnosis of transient hypogammaglobulinemia in infants is based on low immunoglobulin values and the ability to form antibodies after vaccination, which is not seen in persistent (aggressive) hypogammaglobulinemia. 27. Diseases of cellular immunity Hypoplasia of the thymus (DiGeorge syndrome) With this syndrome, embryonic cells are affected in utero, from which the parathyroid glands and thymus develop. As a result, the parathyroid glands and thymus are either underdeveloped or completely absent in the child. The tissues from which the face is formed are also affected. This is expressed by underdevelopment of the lower jaw, a short upper lip, characteristic palpebral fissures, low position and deformation of the auricles. In addition, children have congenital disorders of the heart and large vessels. The disease appears sporadically, but there are suggestions that it is genetically determined and inherited in an autosomal recessive manner. Clinically, DiGeorge syndrome manifests itself already at birth. Disproportions of the face, heart defects are characteristic. The most characteristic symptom in the neonatal period is hypocalcemic convulsions (due to underdevelopment of the parathyroid glands). Immunodeficiency syndrome develops more often in the second half of the life of an infant and is clinically manifested by frequently recurring infections caused by viruses, fungi and opportunistic bacteria, up to severe septic processes. Depending on the degree of underdevelopment of the thymus, the symptoms of immune deficiency can be very different (from severe to mild), and therefore, in mild cases, they speak of partial DiGeorge syndrome. In the blood, a reduced level of calcium and an increased level of phosphorus and a decrease or complete absence of parathyroid hormone are found, which confirms the underdevelopment or absence of the parathyroid glands. Severe combined immunodeficiency states A group of diseases of the immune system, called severe combined immunodeficiency states, has been identified. Enzyme (enzyme) defects were revealed in the pathogenesis. Such immunodeficiencies are relatively rare diseases. They occur in cases from 1:20 to 000:1 in newborns. Despite a similar clinical picture, severe combined immunodeficiencies are divided into several subgroups based on pathogenetic and pathophysiological principles. 28. Swiss type Adenosine deaminase deficiency In most cases, this type of disease is hereditary. Inheritance can be either X-linked recessive or autosomal recessive. In these diseases, the reproduction and differentiation of B-lymphocytes and T-lymphocytes are impaired. A decrease in the concentration of T-cells and immunoglobulins (antibodies) in the blood is characteristic. Often this pathology is accompanied by other malformations. Adenosine deaminase deficiency In severe combined immunodeficiencies, approximately 1/3 and 1/2 of patients have a deficiency of the enzyme adenosine deaminase. The lack of this enzyme leads to the accumulation of adenosine monophosphate, which in high concentrations is toxic to lymphocytes. The manifestations of the disease are typical for patients with severe combined immunodeficiency, but in about 50% of cases, cartilage tissue abnormalities are also observed. Previously, these patients were classified as immunodeficient with short stature and short limbs. In the blood, a pronounced leukopenia is found, as well as the absence of granulocytes and their precursors in the bone marrow. There are no JgA and JgM in the blood, and the amount of JgJ corresponds to the values of JgJ that entered the child's body through the placenta from the mother. The main clinical symptom of this group of diseases is a pronounced tendency to infectious diseases that appear from the first month of a child's life and are most often extensive: all contact surfaces of the body (skin, digestive system, respiratory tract) are affected. Pyoderma, abscesses and various types of rash are observed. Lesions of the gastrointestinal tract manifest as recurrent, refractory diarrhea that causes severe malnutrition. Respiratory tract infections are complicated by deep dry, whooping cough, pneumonia. Children often have prolonged hyperthermia, which is an expression of hematogenous sepsis or meningitis. Under such conditions, infectious processes are caused by a wide variety of microorganisms: saprophytic bacteria and bacteria that cause purulent inflammation, viruses, protozoal pathogens and fungi. In laboratory studies, severe lymphopenia is established. The number of B- and T-cells in the blood is significantly reduced, and the thymus gland is not detected on x-ray. Usually, the clinic manifests itself after the third month of the child's life, that is, when the JgJ transferred from the mother's body through the placenta before delivery is exhausted. Hema-glutinins and specific antibodies are not found in the blood after immunizations. Cellular immunity is significantly impaired. In such patients, the nodes are very small with structural changes, in the mucous membranes of the intestines there is severe atrophy of the lymphatic system. If the thymus gland is found, then very characteristic changes in morphology, structural disturbances, severe lymphopenia, and the absence of Hassal's bodies are noted in it. 29. Wiskott-Aldrich and Louis-Barr Syndromes This syndrome is characterized by a triad: thrombocytopenia, eczema, and increased susceptibility to infectious diseases. It is inherited recessively, transmitted with the X chromosome, and is relatively rare. Clinically, this disease manifests itself very early, already in the neonatal period. Children have skin hemorrhages, mostly petechial, and bloody diarrhea. In a later period, nosebleeds appear. Hemorrhages are fatal. In the first three months of life, eczema appears, often complicated by hemorrhages. There may be other manifestations of allergy with high eosinophilia. In the first half of a child's life, severe respiratory tract infections, complicated eczema, meningitis, and sepsis appear during the course of the disease. With age, the immune deficiency deepens and aggravates. The most common infectious agents are pneumococci, which cause recurrent pneumonia, otitis media, meningitis, and sepsis. These diseases occur in early infancy. When cellular immunity is already affected, diseases can be caused by fungi and viruses. Of interest is the fact that in the Wiskott-Aldrich syndrome, a rather high risk of diseases with malignant tumors, amounting to 10-15%, was revealed. Ataxia, telangiectasia (Louis-Barr syndrome) Louis-Barr syndrome is a complex disease of the immune, nervous and endocrine systems, with frequent damage to the skin and liver. The disease is inherited through a pathological autosomal recessive gene. A characteristic symptom of the disease is progressive cerebral ataxia, which usually appears at school age in children who were healthy before this age. At the age of three to six years, telangiectasias (changes in the vessels) are established. Most often, the conjunctiva is affected (small veins are greatly dilated and tortuous). Such expansions are observed on the auricles and on the cheeks. In this case, the skin looks prematurely aged, and graying of the hair during puberty is common. In patients, in 80% of cases, a tendency to infections that affect mainly the respiratory tract is found. Generalization of the infectious process and damage to the digestive system is not observed. In addition to the main symptoms, there are also endocrinological abnormalities (genital disorders, short stature, glucose intolerance, insulin resistant diabetes mellitus) and hepatic dysfunction. Patients have a tendency to malignant diseases of the lymphoreticular type. In this disease, selective JgA deficiency is a common immunological abnormality, while JgJ values are normal or slightly reduced, and JgM concentration is normal or elevated. JgE levels are usually low. Most patients have signs of impaired cellular immunity. The total number of lymphocytes is reduced slightly, and the number of circulating T-lymphocytes is significantly reduced. 30. Chronic granulomatous disease. Acquired immunodeficiencies This disease is classified as a congenital immune disease associated with impaired phagocytic function of neutrophilic leukocytes. In this disease, granulocytes are unable to destroy microorganisms. It occurs relatively rarely. It can be inherited through a recessive, X-linked, abnormal gene, or through an autosomal recessive gene. It is clinically manifested by numerous recurrent infections that appear in the earliest period of life. The skin is most often affected, on which small abscesses first appear, which quickly penetrate into the underlying tissues and are very difficult to heal. Most have lesions of the lymph nodes (especially the cervical) with the formation of abscesses. Often there are also cervical fistulas. The lungs may be affected, which is manifested by recurrent pneumonia, the digestive system in the form of inflammatory processes in the esophagus, liver, and also in the mediastinum. In the blood, a pronounced leukocytosis with a shift to the left, an increase in ESR, hyper-gammaglobulinemia, and anemia are detected. The prognosis of chronic granulomatous disease is poor. Most of the patients die in preschool age. Immunodeficiency with complement deficiency Complement refers to humoral immunity (from Latin gumor - "liquid"). This is a group of proteins circulating in the blood serum that prepare bacteria and their toxins for phagocytosis, and are also capable of directly destroying microorganisms. An insufficient amount of complement leads to the fact that the body struggles with microbes with great difficulty, and this leads to the development of severe infectious diseases (up to sepsis). In some diseases, such as systemic lupus erythematosus, secondary complement deficiency may develop. Acquired immune deficiencies They are also called secondary immunodeficiencies, as they appear during a person's life for a variety of reasons. In other words, they arise as a result of the impact of many damaging factors on the body, which at birth had a healthy immune system. These damaging factors can be: 1) unfavorable ecology (pollution of water, air, etc.); 2) eating disorders (irrational diets that cause metabolic disorders, starvation); 3) chronic diseases; 4) prolonged stress; 5) not completely cured acute bacterial and viral infections; 6) diseases of the liver and kidneys (organs that provide detoxification of the body); 7) radiation; 8) incorrectly selected medicines. 31. Autoimmune diseases. Systemic vasculitis These diseases can occur when exposed to adverse environmental factors. The basis of the pathogenesis of autoimmune pathologies is a violation of the work of T-lymphocytes (suppressors). As a result, the immune system begins to show aggression against its own (healthy) cells of its own body. There is a "self-harm" of tissues or organs. Autoimmune diseases have a hereditary predisposition. These diseases include rheumatoid arthritis, systemic lupus erythematosus, periarthritis nodosa, scleroderma, systemic vasculitis, dermatomyositis, rheumatism, ankylosing spondylitis (Bekhterev's disease), some diseases of the nervous system, such as multiple sclerosis, etc. All autoimmune diseases there is a vicious circle development. Schematically, this circle can be described as follows. When foreign agents (bacteria, viruses, fungus) invade the cell, an inflammatory reaction develops, which aims to isolate and reject the harmful agent. At the same time, its own tissue changes, dies off and becomes foreign to the body itself, and the production of antibodies already begins on it, as a result of which inflammation develops again. When it reaches the stage of necrosis, the necrotic tissue also becomes an antigen, a harmful agent, against which antibodies are again produced, resulting in inflammation again. Antibodies and inflammation destroy this tissue. And so it goes on endlessly, forming a painful and destructive circle. The primary agent (bacteria, virus, fungus) is gone, and the disease continues to destroy the body. The group of autoimmune diseases is quite large, and the study of the mechanisms of development of these diseases is of great importance for the development of tactics for their treatment and prevention, since most of these diseases lead patients to disability. A particularly significant proportion of autoimmune diseases is occupied by collagenoses, vasculitis, rheumatic lesions of the joints, heart, and nervous system. Systemic vasculitis This is a group of diseases in which there is a systemic vascular lesion with an inflammatory reaction of the vascular wall. There are primary and secondary systemic vasculitis. In primary, systemic vascular lesions are an independent disease, while secondary ones develop against the background of some infectious-allergic or other disease. Secondary systemic vasculitis in diseases such as rheumatoid arthritis, systemic lupus erythematosus, scleroderma, are of paramount importance in the clinical picture of these diseases. Primary systemic vasculitis includes hemorrhagic vasculitis, giant cell temporal arteritis, Wegener's granulomatosis, thromboangiitis obliterans, Goodpasture's, Moshkovich's, Takayasu's syndromes. 32. Rheumatoid arthritis This is a systemic disease of the connective tissue, which is manifested mainly by progressive inflammation of the joints. The causes of occurrence are not well known. The most probable is the immunogenetic theory. It suggests the presence of a genetically determined defect in the immune system. The mechanism of the development of the disease is associated with autoimmune disorders. The main disorders concern the so-called rheumatoid factors, which are antibodies to immunoglobulins. Immunocomplex processes lead to the development of synovitis, and in some cases to generalized vasculitis. In the synovial membrane, granulation tissue is formed and grows, which eventually destroys cartilage and other parts of the bones with the occurrence of erosions (usur). Sclerotic changes develop, fibrous and then bone ankylosis occurs (the joint is deformed and becomes stiff). Pathological changes occur in the tendons, serous bags and joint capsule. Clinically, the disease is manifested by persistent inflammation of the joint (arthritis). But the most common is polyarthritis, which affects mainly small joints (metacarpophalangeal, interphalangeal and metatarsophalangeal). There are all signs of inflammation (pain, swelling of the joints, local fever). The disease is characterized by a gradual, slow, but steady progression of arthritis and the involvement of new joints in the pathological process. The advanced stage of the disease is characterized by deforming arthritis. Deformities of the metacarpophalangeal (flexion contractures, subluxations) and proximal (distant) interphalangeal joints are especially typical. These changes form the so-called rheumatoid hand and rheumatoid foot. In rheumatoid arthritis, it is rare, but extra-articular manifestations are also observed. These include subcutaneous nodules, often located in the elbow joints, serositis (inflammation in the pleura and pericardium), lymphadenopathy, and peripheral neuropathy. The severity of extra-articular manifestations, as a rule, is small. Usually they do not come to the fore in the overall picture of the disease. Approximately 10-15% of patients develop kidney damage in the form of amyloidosis with gradually increasing proteinuria, nephrotic syndrome, which ends with renal failure. Laboratory indicators are nonspecific. In 70-80% of patients, rheumatoid factor (Waaler-Rose reaction) is detected in the blood serum. This form of rheumatoid arthritis is called seropositive. From the very beginning of the disease, there is an increase in ESR, fibrinogen, "2-globulins, the appearance of C-reactive protein in the blood serum, a decrease in hemoglobin levels. All these indicators usually correspond to the activity of the disease. 33. Hemorrhagic vasculitis Wegener's granulomatosis These are systemic lesions of capillaries, arterioles, venules. The process takes place mainly in the skin, joints, abdominal cavity, kidneys. The disease usually occurs in children and adolescents, less often in adults of both sexes. The development of the disease occurs after an infection (streptococcal tonsillitis or exacerbations of chronic tonsillitis or pharyngitis), as well as after vaccination, due to drug intolerance, hypothermia, etc. Damage to blood vessels in the form of microthrombosis, hemorrhages (hemorrhages), changes in the inner lining of the artery (endothelium) has an immune genesis. Damaging factors are immune complexes circulating in the blood. Clinically, the disease is manifested by a triad: 1) small-celled, sometimes merging hemorrhagic rashes on the skin (purpura); 2) pain in the joints or inflammation of the joints, mostly large ones; 3) abdominal syndrome (pain in the abdominal cavity). The rash is more common on the legs. Initially, skin rashes are located on the extensor surfaces of the limbs, sometimes on the trunk, often ending with residual pigmentation. More than 2/3 of patients have migrating symmetrical polyarthritis, usually of large joints. Inflammation of the joints is often accompanied by hemorrhages inside the joint cavity, which leads to pain of a different nature: from a slight ache to severe pain, up to immobility. Wegener's granulomatosis Granulomatous-necrotic vasculitis with a primary lesion of the respiratory tract, lungs and kidneys. The reason is not yet known. The disease is provoked by colds (ARVI), cooling, overheating in the sun, trauma, drug intolerance, etc. The leading mechanisms for the development of the disease are autoimmune. The disease develops more often in men. First, the respiratory tract is affected, which manifests itself in two ways. In the first variant, there is a persistent runny nose with serous-sanitary, purulent discharge, nosebleeds, in the second - a persistent cough with bloody-purulent sputum, pain in the chest. Further the clinical picture with many syndromes develops. This is the stage of generalization, which is accompanied by fever, transient polyarthritis or only pain in the joints and muscles, skin lesions (up to severe necrotic lesions of the skin of the face), etc. laryngitis. Clinical and radiological symptoms in the lungs are manifested in the form of focal and confluent pneumonia with the formation of abscesses and cavities. At this stage, the kidneys, heart, nervous system, etc. are involved in the pathological process. In blood tests, changes are not specific (bright signs of inflammation - leukocytosis, accelerated ESR). The prognosis of the disease is often unfavorable. Patients die of pulmonary heart or kidney failure, pulmonary hemorrhage. The diagnosis is made on the basis of a biopsy of the mucous membranes of the respiratory tract, lungs, where the granulomatous nature of the disease is revealed. 34. Giant cell arteritis. Goodpasture's syndrome This is a systemic disease with a predominant lesion of the temporal and cranial arteries. A viral etiology is assumed, and the mechanism of development (pathogenesis) is an immunocomplex lesion of the arteries, which is confirmed by the detection of fixed immune complexes in the wall of the arteries. The granulomatous type of cellular infiltrates is also characteristic. Elderly people of both sexes get sick. With the most common variant, the disease begins acutely, with high fever, headaches in the temporal region. There is a visible thickening of the affected temporal artery, its tortuosity and pain on palpation, sometimes reddening of the skin. When the diagnosis is made late, damage to the vessels of the eye and the development of partial or complete blindness are observed. From the first days of the disease, the general condition also suffers (lack of appetite, lethargy, weight loss, insomnia). In blood tests, high leukocytosis, neutrophilia, accelerated ESR, hyper-o^ and gamma globulinemia are determined. The course of the disease is progressive, but early treatment can lead to permanent improvement. Goodpasture's syndrome This is a systemic capillaritis with a primary lesion of the lungs and kidneys in the form of hemorrhagic pneumonia (with hemorrhages in the lung tissue) and glomerulonephritis (damage to the renal glomeruli). Men of young age (20-30 years) get sick more often. The reason is not clear, but a connection with a viral or bacterial infection, hypothermia is considered more likely. It is characteristic that for the first time this disease was described during the influenza epidemic in 1919. The pathogenesis is autoimmune, since antibodies to the basement membranes of the kidneys and lungs are found circulating and fixed in the tissues. Electron microscopic examination shows changes in the basement membranes of the alveoli of the lungs and renal capillaries in the form of fixation of antibodies to these basement membranes. Clinically, the disease begins acutely, with high fever, hemoptysis or pulmonary hemorrhage, shortness of breath. In the lungs, an abundance of moist rales is heard in the middle and lower sections, and on x-rays there are many focal or confluent opacities on both sides. Almost simultaneously, severe, rapidly progressing glomerulonephritis develops with nephrotic syndrome (edema, protein and blood in the urine) and the rapid development of renal failure. The prognosis is often unfavorable, patients die in the next six months or a year from the onset of the disease from pulmonary and cardiac and renal failure. Anemia, leukocytosis and accelerated ESR are found in the blood. The immunological sign of the disease is antibodies to the basement membranes of the kidney. 35. Moshkovich's syndrome Takayasu syndrome Thrombotic thrombocytopenic purpura (Moshkovich's syndrome) This is a systemic thrombotic microangiopathy, which is accompanied by thrombocytopenic purpura, intravascular coagulation (hemolysis), cerebral and renal symptoms. The cause and mechanism of the development of the disease is not yet known. Assume the immune nature of a disease. Mostly young women get sick. The disease begins suddenly, with fever, signs of intravascular coagulation, thrombocytopenic purpura, and various neuropsychiatric disorders due to brain damage. Other organs are also affected, primarily the kidneys with the rapid development of renal failure. Clinically, the disease is manifested by hemorrhagic syndrome, petechial (small cell) hemorrhages on the skin, nasal, gastric, gynecological, renal bleeding, hemorrhages in the fundus. Blood tests reveal anemia, reticulocytosis (immature blood cells), thrombocytopenia (lack of platelets), elevated bilirubin, and hyper-gammaglobulinemia. The course is steadily progressive with a rapid lethal outcome. Takayasu syndrome (aortic arch syndrome, pulseless disease) This syndrome is an inflammatory process in the aortic arch (aortitis) and in the branches extending from it. At the same time, their partial or complete obliteration develops. Other parts of the aorta may also be affected. The causes (etiology) and mechanisms (pathogenesis) of this disease are not yet clear. The importance of immune disorders, which are based on genetic defects in the formation of the aortic wall, is assumed. More often young women are ill. The syndrome is manifested by a gradual increase in signs of circulatory disorders in the areas of the affected vessels. The main symptom is the absence of a pulse in one or both hands, less often in the carotid, subclavian, temporal arteries. Patients feel pain and numbness in the limbs, which are aggravated by physical exertion, weakness in the arms, dizziness, often with loss of consciousness. When examining the eyes, cataracts, changes in the vessels of the fundus (narrowing, the formation of arteriovenous anastomoses) are detected. Significantly less often, coronary arteries with corresponding symptoms are involved in the process. When the abdominal aorta with renal vessels is affected, vasorenal (renal) hypertension develops. Of the common signs of the disease, subfebrile condition and asthenia are characteristic. Laboratory indicators are moderate. The disease progresses slowly, with exacerbations in the form of ischemia of a particular zone. Diagnosis can be made at an early stage by arteriography. 36. Systemic lupus erythematosus It is a chronic systemic autoimmune disease of the connective tissue and blood vessels. This serious autoimmune disease is caused by a chronic viral infection. These are RNA viruses that are close to measles or measles-like. The mechanism of the development of the disease is quite complex. Circulating autoantibodies are formed in the body, of which antinuclear antibodies to the whole nucleus and its individual components are of the most important diagnostic value, circulating immune complexes, primarily DNA antibodies to complement DNA, which are deposited on the basement membranes of various organs, cause their damage with inflammatory reaction. The disease has a gradual onset. Appear asthenia (weakness), recurrent polyarthritis. Much less often there is an acute onset, characterized by fever, dermatitis, acute polyarthritis, and then there is a course with relapses and multisyndromic symptoms. Multiple joint lesions (polyarthritis) and pain in them are the most frequent and early symptoms. The lesions mainly affect the small joints of the hands, wrists, ankles, but the knee joints can also be affected. The severity and persistence of the lesion are different. A characteristic symptom of the disease is skin lesions in the form of erythematous rashes on the face (redness) in the form of a butterfly, i.e. on the bridge of the nose, cheeks and in the upper half of the chest in the form of a decollete, as well as on the extremities. Dermatitis, polyarthritis, and polyserositis are the diagnostic triad of systemic lupus erythematosus. Characterized by damage to the cardiovascular system. Pericarditis usually develops with further addition of myocarditis. Libman-Sachs verrucous endocarditis is often observed with damage to the mitral, aortic and tricuspid valves. Vascular damage occurs in individual organs, but Raynaud's syndrome is possible, which appears long before the development of a typical picture of the disease. Lung damage is associated with a vascular connective tissue syndrome that develops with the underlying disease and with a secondary infection. The so-called lupus pneumonia is manifested by cough, shortness of breath, unvoiced moist rales in the lower parts of the lungs. X-ray reveals an increase and deformation of the pulmonary pattern due to the vascular component in the lower parts of the lungs, sometimes focal-like shadows are found. Pneumonia develops against the background of polyserositis, therefore, on x-rays, additionally with basic changes, a high standing of the diaphragm with signs of adhesions and the so-called linear shadows parallel to the diaphragm (disc-shaped lung tissue seals) are detected. In the early stages of the disease, there is an increase in the liver, although lupus hepatitis itself is extremely rare. As a rule, liver enlargement is due to heart failure, pancarditis (damage to the pericardium, myocardium and endocardium), or severe effusion pericarditis. Could be fatty liver. 37. Clinical picture of systemic lupus erythematosus A frequent and early sign of systemic disease is an increase in all groups of lymph nodes and spleen, which indicates damage to the reticuloendothelial system. Lupus nephritis, the so-called lupus nephritis, develops in 50% of patients. Its development usually occurs during the period of generalization of the process. Kidney damage in systemic lupus erythematosus has several options: urinary, nephritic or nephrotic syndrome. In the diagnosis of lupus nephritis, intravital puncture biopsy with a deep study of the biopsy (immunomorphological and electron microscopic) is of great importance. The combination of fever, recurrent articular syndrome and persistently accelerated ESR requires the exclusion of lupus nephritis. Observations show that almost every fifth patient with nephrotic syndrome has systemic lupus erythematosus. In many patients in all phases of the disease, damage to the neuropsychic sphere is noted. At the initial stage of the disease, asthenovegetative syndrome is observed, and then signs of damage to all parts of the central and peripheral nervous system develop in the form of encephalitis, myelitis, polyneuritis. Often there are combined lesions (systemic) of the nervous system in the form of meningoencephalo-, myelo-polyradiculoneuritis. Laboratory data are of great diagnostic value, especially for the detection of a large number of LE cells (lupus cells, or lupus). High titers of antibodies to DNA are specific for systemic lupus erythematosus. In the case of an acute (rapid) development of the disease, lupus nephritis is detected already after 3-6 months, which proceeds according to the type of nephrotic syndrome. In the subacute course, undulation is characteristic with the involvement of various organs and systems in the pathological process, which in the clinical picture is manifested by polysyndromicity. The chronic long-term course of the disease is characterized by relapses of polyarthritis and (or) polyserositis, Raynaud's syndrome and epileptiform convulsions. Only in the 5-10th year does a characteristic polysyndromicity gradually develop. In accordance with the clinical and laboratory characteristics, three degrees of activity of the process are distinguished: high (III degree), moderate (II degree) and minimal (I degree). Patients need long-term continuous treatment. The best results are observed with early treatment, then a stable clinical remission develops. 38. Dermatomyositis (polymyositis) Refers to systemic diseases of the connective tissue with a primary lesion of the muscles and skin. It is assumed that the trigger of this disease is a viral infection, and the provoking factors are cooling, trauma, prolonged exposure to the sun, pregnancy, drug intolerance. 20-30% of patients may have tumor dermatomyositis. The pathogenesis is based on autoimmune disorders. The clinical onset of the disease can be either acute or gradual. The muscle syndrome comes to the fore in the form of muscle weakness and muscle pain (myasthenia gravis and myalgia). No less significant manifestations of the disease are arthralgia, fever, skin lesions, dense widespread edema. In the future, the disease acquires a relapsing course. In all patients, skeletal muscles are affected. This is manifested by myalgia during movement and at rest, as well as with pressure, and increasing muscle weakness is characteristic. In the early stages of the disease, the muscles are painful and often swollen, later they undergo dystrophy and myolysis (resorption of muscle fibers). In even later stages of the disease, myofibrosis develops in place of muscle fibers (replacement of muscle tissue with connective tissue), which leads to muscle atrophy and contractures. There may be calcification (calcium deposition) in the muscles, subcutaneous tissue, especially often in young people. Calcification is easily detected on x-ray. With electromyography, changes are nonspecific. A variety of skin lesions are characteristic. These are all kinds of rashes in the form of reddened areas of the skin, the appearance of tubercles and blisters, expansion of skin vessels, keratinization of certain areas of the skin, depigmentation or hyperpigmentation, etc. Often these rashes are accompanied by itching. Very pathognomonic is the presence of peri-orbital (around the eyes) edema with purple-purple erythema - the so-called dermatomyositis glasses. The joints are affected in the form of polyarthralgia (pain in many joints at once), up to the development of joint stiffness. There is a lesion of the myocardium of an inflammatory or dystrophic plan. With diffuse myocarditis, a severe picture of heart failure develops. Raynaud's syndrome is observed in 1/3 of patients. Frequent lung damage due to hypoventilation. In almost half of the patients, the gastrointestinal tract is involved in the pathological process. This is manifested by anorexia, abdominal pain, gastroenterocolitis, decreased tone of the upper third of the esophagus. Sometimes there are symptoms that simulate intestinal obstruction. Data from laboratory studies are nonspecific. Usually this is moderate leukocytosis with severe eosinophilia (up to 25-70%), persistent moderate acceleration of ESR, hypergammaglobulinemia. Biochemical studies of blood and urine, muscle biopsy are important for diagnosis. In an acute course, a catastrophically increasing generalized lesion of the striated muscles is observed, up to complete immobility. Patients cannot swallow or speak. There is a general serious condition with fever, toxicosis and various skin rashes. If left untreated, death usually occurs within 3-6 months. The main causes of poor outcome are aspiration pneumonia, pulmonary heart failure. 39. Nodular periarteritis This is a systemic vascular disease with a predominant lesion of the arteries of the muscular type and vessels of a smaller caliber. A disease occurs for an unknown reason. In pathogenesis, the main thing is the highest (hyperergic) reaction of the body in response to the influence of various factors. An essential role is played by immune complexes circulating and fixed in the vessel wall. Mostly men aged 30-40 years get sick. The onset of the disease is acute or gradual, with such general symptoms as fever, progressive weight loss, pain in the joints, muscles, abdomen, skin rashes, lesions of the gastrointestinal tract. Over time, the heart, kidneys, and peripheral nervous system are affected, i.e., polyvisceral symptoms develop (all organs are affected). Almost all patients have glomerulonephritis of varying severity: from mild nephropathy with transient (transient) hypertension and moderate urinary syndrome to diffuse glomerulonephritis with persistent hypertension and a rapidly progressive course. Unfavorable in terms of prognosis is the development of the syndrome of malignant hypertension and nephrotic syndrome, which quickly leads to renal failure. Acute pain in the abdomen is very characteristic of periarteritis nodosa. They are associated with the pathological process in the vessels of the abdominal cavity. The defeat of the vessels of the stomach leads to gastritis, the defeat of the vessels of the small intestine - to enteritis, etc. Appendicitis, acute cholecystitis, pancreatitis, intestinal perforation due to necrosis, infarction, hemorrhages may develop. In 50% of patients, damage to the nervous system is manifested by multiple neuritis associated with pathology in the vessels that feed one or another nerve. Possible meningoencephalitis with impaired speech and hearing, headache and dizziness, convulsions, as well as focal brain lesions due to thrombosis, aneurysm rupture. One of the early symptoms of the disease is eye damage. Examination of the fundus reveals arterial aneurysms, thrombosis of the central retinal artery, etc. A feature of periarteritis nodosa is the rapidly developing pronounced pallor of patients, which, in combination with exhaustion, creates a picture of chlorotic insanity. Lung damage is manifested by pneumonia and bronchial asthma. Pulmonary symptoms are associated with vascular damage. There are observations indicating that bronchial asthma may precede the full picture of periarteritis nodosa by many years. Laboratory data are uncharacteristic. Possible leukocytosis with neutrophilic shift, eosinophilia, sometimes high. In severe cases, moderate anemia and thrombocytopenia occur. To clarify the diagnosis, a muscle biopsy is performed from the lower leg or abdominal wall. At the same time, vascular changes characteristic of this disease are revealed. 40. Rheumatism Systemic inflammatory disease of the connective tissue with predominant localization in the heart. Children and young people usually get sick. Women get sick about 3 times more often than men. The main cause of the disease is group A β-hemolytic streptococcus. However, in patients with prolonged and continuously recurrent forms of rheumatic heart disease (rheumatic heart disease), the association of the disease with streptococcus is often not established, although heart damage fully meets all the main criteria for rheumatism. This indicates other reasons for the development of rheumatism: allergic (out of connection with streptococcus or infectious antigens in general), infectious-toxic, viral. Allergy plays an important role in the development of rheumatism. It is assumed that sensitizing agents (streptococcus, virus, nonspecific allergens, etc.) can lead to allergic inflammation in the heart at the first stages, and then to a change in the antigenic properties of its components with their transformation into autoantigens and the development of an autoimmune process. Genetic predisposition plays an important role. Morphologically, the systemic inflammatory process in rheumatism manifests itself in characteristic phase changes in the connective tissue. This is mucoid swelling - fibrinoid change - fibrinoid necrosis. Clinical manifestations of the disease in typical cases develop 1-2 weeks after suffering a sore throat or other infection. But with repeated attacks, this period may be shorter. In some patients, even primary rheumatism occurs 1-2 days after cooling without any connection with infection. Exacerbations develop after any concomitant diseases, operations, physical exertion. In the first period of the disease, fever is often noted (usually subfebrile), the general condition is unchanged. In some patients with polyarthritis or serositis, the condition can be severe: with high persistent fever up to 38-40 ° C with daily fluctuations of 1-2 ° C and strong sweats (but without chills). However, in recent years, this condition has been observed extremely rarely. Rheumatic myocarditis. This disease in adults, as a rule, is not particularly severe. Patients complain of mild pain and vague discomfort in the region of the heart, slight shortness of breath during exertion, less often - of palpitations or interruptions in the heart. On x-ray, the heart is of normal size or moderately enlarged. Circulatory failure practically does not develop. Rheumatic endocarditis. It proceeds in isolation and is very poor in general symptoms. The main signs of rheumatic endocarditis are systolic and diastolic murmurs, which appear to be due to thrombotic overlays on inflammatory valves. If endocarditis is the only localization of rheumatism, then patients constitute the so-called outpatient group. This means that with this course of rheumatism, good general health and ability to work are maintained for a long time. After a certain time, a heart disease is formed with concomitant hemodynamic disorders, and this makes patients see a doctor for the first time. 41. Pericarditis Dry pericarditis is manifested by constant pain in the region of the heart and pericardial friction rub. Exudative pericarditis is characterized by the accumulation of serous-fibrous exudate in the heart sac and is essentially the next stage of dry pericarditis. Characterized by shortness of breath, which increases in the supine position. With a significant accumulation of exudate, the region of the heart swells somewhat, the intercostal spaces are smoothed, the apex beat is not palpated. The enlargement of the heart is significant, it takes the characteristic shape of a trapezoid or a round decanter. Tones and noises are very muffled. Often the outcome of rheumatic pericarditis are small adhesions between the outer sheet and surrounding tissues. Much less common is the complete fusion of the sheets of the heart bag, i.e., an adhesive obliterating pericarditis develops, the so-called armored heart. Rheumatic vascular disease. With rheumatism, the vessels in the internal organs (arteritis of the internal organs) are mainly affected, which is the basis for the manifestations of rare rheumatic visceritis: nephritis, meningitis, encephalitis, etc. Joint damage. Currently, acute rheumatic fever is relatively rare. Characteristic manifestations of rheumatic polyarthritis are increasing acute pain in the joints, aggravated by movement and palpation. Within a few hours, the pain becomes extremely sharp. Very quickly, symptoms of joint damage join the pains: swelling, sometimes hyperemia. Symmetrical lesions of large joints and volatility of arthritis are characteristic. Rheumatoid arthritis is completely reversible: all articular manifestations (regardless of their severity at the onset of the disease) disappear without a trace. Skin lesions. With rheumatism, skin lesions occur in the form of rheumatic nodules, annular or nodular erythema, urticaria, etc. Rheumatic nodules are usually located in the area of the affected joints, over bony prominences, in the occipital region, on the forearms and legs. Rheumatic lesions of the lungs. There are rheumatic pneumonias and pleurisy, but this is extremely rare. Usually they occur against the background of already developed rheumatism. Pleurisy in rheumatism is often bilateral and well reversible. Rheumatic nephritis is rare, and antirheumatic drugs are especially effective in their treatment. Rheumatic affections of the digestive organs. Such rheumatic lesions have no significant clinical significance. Gastritis or ulcers of the stomach and intestines are the consequences of long-term medication, especially steroid hormones. Only children suffering from rheumatism sometimes have severe abdominal pain associated with allergic peritonitis, which quickly passes, that is, is completely reversible. 42. Laboratory data for pericarditis Patients with the maximum degree of activity of the process have neutrophilic leukocytosis up to 12-15x103. At the same time, there is a shift of the formula to the left due to an increase in stab leukocytes. Metamyelocytes and myelocytes may appear in the leukogram. In most patients, the number of leukocytes and the leukogram are not significant. In the acute period of the disease, the number of platelets is increased, but this increase does not last long. Most patients with rheumatism have an accelerated ESR, reaching maximum numbers (40-60 mm / h) with polyarthritis and polyserositis. Shifts in immunological indicators are very characteristic. These include an increase in titers of antistreptococcal antibodies (antistreptohyaluronidase, antistreptokinase, antistrepto-lysine). An increase in the level of these antibodies reflects the body's reaction to exposure to streptococci, and therefore often occurs after any streptococcal infections (as well as detection in the blood or urine of streptococcal antigens). But the height of titers of anti-streptococcal antibodies and their dynamics do not reflect the degree of activity of rheumatism. In very many patients with chronic forms of rheumatism, there are no signs of participation of streptococcal infection at all. Biochemical indicators of the activity of the rheumatic process are non-specific, that is, they occur in various types of inflammation and tissue decay. In cases where the diagnosis of rheumatism is justified by clinical and instrumental data, biochemical studies are important to determine the activity of the disease. These biochemical studies include an increase in the level of fibrinogen, an increase in o-globulins, gamma globulins, hexoses, ceruloplasmin, seromucoid, diphenylamine reactions, etc. But the most revealing and accessible of all biochemical studies is the detection of C-reactive squirrel. In most cases, biochemical indicators of activity are parallel to the values of ESR, which is the best laboratory sign of the activity of rheumatism, as well as its dynamics. There are two phases of rheumatism: inactive and active. The activity of the disease can be of three degrees: the first degree is minimal, the second degree is average, the third degree is maximum. The activity of rheumatism is judged by the severity of clinical manifestations and changes in laboratory parameters. In modern conditions, the nature of the course of the disease has changed significantly. The number of patients with bright, violent manifestations and a protracted and continuously relapsing course has sharply decreased. Other visceral lesions became casuistry. Suspicion of rheumatism should be caused by any disease that occurs 1-3 weeks after a sore throat or other nasopharyngeal infection and is characterized by signs of damage to the joints and heart. Significant diagnostic criteria are objective evidence of cardiac involvement, rapidly reversible arthritis of the large joints, chorea minor, erythema annulare, and subcutaneous nodules with rapid regression. The prognosis for rheumatic lesions is based mainly on the degree of reversibility of the symptoms of rheumatic heart disease. The most unfavorable are continuously recurrent rheumatic carditis, which lead to the formation of heart defects, myocardiosclerosis. Rheumatism is more severe in children. In them, it often leads to persistent changes in the valves of the heart. Also, the likelihood of developing heart defects increases with late treatment. 43. Reiter's syndrome Spondylitis ankylosing It is a disease of unclear etiology with a characteristic combination of arthritis, urethritis, conjunctivitis, and in some cases, a kind of dermatitis. In the development of the disease, it is considered likely that the genetic characteristics of the immune system play a decisive role. The disease affects mainly young men. Often the disease is preceded by non-gonococcal urethritis or acute intestinal upset. Clinically, arthritis ranges from moderate, transient to severe, prolonged, or recurrent. More often one large joint is affected. The duration of arthritis in Reiter's syndrome is from 2 to 6 months, rarely longer. Many patients have lesions of the spine. The severity of urethritis can be different, often it is found only during special examinations or urine tests, i.e., it is almost asymptomatic. Conjunctivitis is usually also not severe, quickly passing. In some cases, there may be dermatitis. Rarely, but lesions of internal organs can occur: arthritis with the development of aortic valve insufficiency, myocarditis, pericarditis, enteritis, polyneuritis, meningoencephalitis. Laboratory data are nonspecific. Disease activity is determined by the value of ESR (acceleration) and an increase in the level of biochemical indicators of inflammation (fibrinogen, C-reactive protein, etc.). The course of the disease varies, spontaneous recovery is often noted. Diagnosis in the presence of the entire triad of symptoms does not cause difficulties. Ankylosing spondyloarthritis (Bekhterev's disease) Chronic inflammatory disease of the joints of the spine with a tendency to develop a gradual limitation of movements in them. The etiology and pathogenesis are not yet clear. Great importance is attached to the genetic characteristics of the immune system. The disease affects mainly men. An obligatory symptom of Bechterew's disease is a lesion of the spine. But this defeat is often limited for a long time only to the sacroiliac joints (sacropleitis). Manifestations of sacropleitis can be vague (in the form of discomfort, unsharp pain) and inconsistent. Sometimes subjective sensations may be completely absent, and only an X-ray examination reveals a lesion of the sacroiliac joint. As the small joints of the spine are involved in the process, pains appear in one or another of its departments (sometimes in the entire spine). Very often the pain intensifies at night, and in the morning there is stiffness. Later, restrictions on the movements of the spine join: the patient cannot reach the floor with his fingers without bending his knees, his chin - the sternum, there is a decrease in the respiratory excursion of the chest. Gradually, the physiological curves of the spine are smoothed out, hyperkyphosis of the thoracic region is formed, i.e., a very characteristic supplicant posture appears. The course of this form of Bechterew's disease (central) is usually slow, long-term, with periods of exacerbations and remissions. The diagnosis is made on the basis of an x-ray examination (radiography), where characteristic changes are found. Sacropleitis is the earliest X-ray symptom of a spinal lesion; in some cases, it develops as early as 4-6 months from the onset of the disease. 44. Systemic scleroderma Chronic systemic connective tissue-vascular disease characterized by progressive fibrosis. The etiology is probably viral, since when examining the affected tissues with an electron microscope, virus-like particles were detected and an increase in the titers of a number of antiviral antibodies was noted. Pathogenetic mechanisms are quite complex and are associated with metabolic and structural disorders on the part of collagen formation and the main substance of the connective tissue. Also in pathogenesis an important role is played by disorders of microcirculation, as well as humoral and cellular immunity. The role of family genetic predisposition is significant. Women get sick three times more often than men. The onset of the disease is usually gradual, rarely acute. Provoking factors are cooling, trauma, infections, vaccinations, etc. More often, the disease begins with Raynaud's syndrome (vasomotor disorders). There are also violations of tissue trophism, joint pain, weight loss, asthenia, fever. As a rule, systemic scleroderma, starting with a single symptom, gradually or rather quickly becomes a generalized multisyndromic disease. The pathognomonic (specific) sign of the disease is a skin lesion. This is a widespread dense edema, and in the future - thickening and atrophy of the skin. The greatest changes occur with the skin of the face and limbs. But often the skin of the entire body becomes dense. At the same time, focal or widespread pigmentation develops with areas of depigmentation and expansion of small vessels. Ulcerations and pustules on the fingertips are characteristic, very painful and do not heal for a long time, deformation of the nails, hair loss (up to baldness) and other trophic disorders. Peripheral symptoms of scleroderma are caused by damage to small arteries, arterioles. The consequences of these lesions are Raynaud's syndrome, telangiectasia, gangrene of the fingers. Damage to the vessels of internal organs leads to severe visceral pathology. Hemorrhages, ischemic phenomena and even necrotic changes in organs are observed. Lung involvement is usually accompanied by emphysema and bronchiectasis due to focal or diffuse pneumofibrosis. Focal nephritis often develops in the kidneys, but in some cases diffuse glomerulonephritis with hypertension and renal failure is possible. Damage to the nervous system is manifested by polyneuritis, vegetative instability, characterized by impaired sweating, thermoregulation, and vasomotor reactions of the skin. There may also be emotional lability, irritability, tearfulness, suspiciousness, insomnia. In very rare cases, a picture of encephalitis or psychosis occurs. Patients suffer mainly from damage to the skin, joints and trophic disorders. In chronic systemic scleroderma, calcification, Raynaud's syndrome, telangiectasia, and finger damage are isolated. All these pathologies are characterized by a long benign course with an extremely slow development of damage to internal organs. Laboratory data are not representative. 45. Sjögren's syndrome Agranulocytosis They are a chronic inflammation of the endocrine glands, mainly salivary and lacrimal, leading to their secretory insufficiency. It may be an isolated syndrome (this is the so-called dry syndrome). The name speaks for itself, since the most striking clinical signs are dry mouth and eyes. The cause of the disease has not been fully elucidated, but the most likely opinion is about autoimmune genesis, which is confirmed by the frequent combination with other diseases of an autoimmune nature: rheumatoid arthritis, systemic lupus erythematosus, systemic scleroderma, etc. Mostly middle-aged women get sick. Sjögren's syndrome is characterized by a combination of dry keratoconjunctivitis (xerophthalmia) and dry stomatitis (xerostomia), which are associated with damage to the lacrimal and salivary glands and secretory insufficiency. Consequences of constant dryness in the mouth are difficult chewing and swallowing. Glossitis (inflammation of the tongue), cheilitis (inflammation of the red border of the lips), progressive dental caries develop. Patients are concerned about constant pain in the joints, periodically swelling, but there are no severe deformities and destructions with dry syndrome. Raynaud's syndrome is also observed, and drug intolerance is often present. Laboratory data are quite characteristic: positive rheumatoid factor, accelerated ESR. Diagnosis is based on two of three features: xerophthalmia, xerostomia, and autoimmune disease. Sjögren's syndrome proceeds as a chronic relapsing disease with involvement of the lymph nodes and internal organs in the process. Agranulocytosis Agranulocytosis is a decrease in the number of leukocytes (less than 1000 in 1 μl of blood) or the number of granulocytes (less than 750 in 1 μl of blood). Haptens are drugs that, when ingested, combine with a protein and acquire the properties of an antigen. Hapten agranulocytosis is caused by diamox, amidopyrine, antipyrine, acetylsalicylic acid, barbiturates, isoniazid (tubazid), meprobamate, phenacetin, butadione, plasmoquine, indomethacin, levamisole, sulfonamides, biseptol, chloroquine, antidiabetic sulfa drugs, insecticides (insecticides). The mechanism of development of agranulocytosis is not well understood. In autoimmune forms of damage, premature death of granulocytes and their bone marrow precursors is caused by autoantibodies. The very mechanism of the body's individual reaction to the ingestion of a drug in hapten agranulocytosis is not yet clear. The prognosis of autoimmune agranulocytosis is determined by the underlying diseases (systemic lupus erythematosus, rheumatoid arthritis, etc.). Hapten-new agranulocytosis gives a high percentage of deaths (up to 80%). The prognosis is sharply aggravated with repeated ingestion of haptens into the body. Since it is often very difficult to establish which drug was a hapten, it is necessary to exclude all suspected drugs from use for life. It is this rule that is the main preventive measure for repeated hapten-type agranulocytosis. 46. Immune hemolytic anemia These are anemias that are caused by the action of antibodies on red blood cells. There are several forms of immune hemolytic anemia. These are autoimmune anemias caused by the formation in the body of antibodies against its own red blood cells; hapten, caused by fixation on erythrocytes of hapten antigens alien to the body (drugs, viruses, etc.) with antibodies formed in response to the combination of the hapten with the protein of the body; isoimmune, associated with the ingestion of maternal antibodies directed against the child's erythrocytes into the body of the newborn (with incompatibility between the child and the mother in terms of the Rh factor and much less often in terms of blood type). Autoimmune hemolytic anemias The basis of the pathological process is the breakdown of immunological insensitivity to its own antigen. The leading symptom of the clinical picture is anemic syndrome. The severity of the condition is determined by the severity and severity of anemia. When the process develops slowly, the first sign of the disease may be a slight jaundice (due to indirect bilirubin), and anemia is also detected at the same time. In other cases, the onset of the disease is rapid, with hemolysis (destruction of red blood cells), rapidly increasing anemia, and jaundice. Often the body temperature rises. Sometimes the spleen and liver are enlarged. A systolic murmur is heard at the apex and base of the heart, which has a functional nature. In the blood test, normochromic anemia is determined, and in the acute course of the disease, the hemoglobin level can drop to catastrophic numbers. Then the patient may fall into an anemic coma. In acute hemolysis, single erythrokaryocytes can be determined in the blood. The level of reticulocytes is also high. The leukogram does not change significantly, but a hemolytic crisis may be accompanied by a short neutrophilic leukocytosis. The platelet count is usually normal. However, autoimmune cytolysis (cell breakdown) occurs, affecting two germs: platelet and erythrocyte (Ivens-Fischer syndrome). In this case, there are signs of hemolytic anemia and thrombocytopenic purpura. The prognosis of the disease cannot be given. It may be the only episode of the breakdown of red blood cells, or it may turn into a chronic hemolytic process. In addition to this most common form of autoimmune hemolytic anemia, in which hemolysis occurs intracellularly, there is a form of the disease with intravascular hemolysis. The difference between these forms is that with intravascular hemolysis, dark urine is released due to hemoglobinuria and hemosiderinuria. The diagnosis of autoimmune hemolytic anemia is made on the basis of the general signs of hemolysis: an increase in the level of bilirubin in the blood or the appearance of bilirubin in the urine, an increase in the percentage of reticulocytes in the blood, and the detection of autoantibodies on the surface of red blood cells using the Coombs test (a special laboratory test), which is positive in almost 60% cases of autoimmune hemolysis. 47. Multiple sclerosis A disease of the nervous system, which is based on the occurrence of demyelination foci scattered throughout the brain and spinal cord, which either disappear with time or are replaced by plaques (gliosis scars). The cause of this disease is not clear enough. Most likely, autoimmune reactions are involved in the mechanism. The demyelinating process mainly affects the white matter of the central nervous system. The affected area undergoes remyelination, after the breakdown of myelin, the axial cylinders are also damaged, followed by the formation of a characteristic dense glial plaque ranging in size from several millimeters to several centimeters. Remyelination (restoration of myelin) underlies clinical remissions. With the development of scars, the functions of the affected areas of the central nervous system are irreversibly lost. The disease usually occurs at a young age. In childhood and after 50 years, the disease develops extremely rarely. The first symptoms of the disease are transient motor, sensory (often numbness) or visual disturbances. Over time, newly emerging lesions are no longer subject to reverse development. There is a steady increase in the severity of the clinical picture. More often than others, the pyramidal and cerebellar systems and the optic nerves are affected. Almost always (in 90% of cases) in the advanced stage of the disease there is lower spastic paraparesis or tetraparesis (weakness in the lower extremities or in the upper and lower extremities). At the same time, cerebellar disorders are expressed: gait disturbances, speech disorders, involuntary movements of the eyeballs (nystagmus). There is a pronounced tremor of the limbs and head, and the trembling is detected during active movements and tension, but it can also be at rest. The combination of nystagmus, speech disorders (chanted speech), and trembling together form the Charcot triad, which is a characteristic feature of multiple sclerosis. Damage to the optic nerves leads to a decrease in visual acuity. On the fundus, blanching of the temporal discs is observed. Urinary disorders are common. Many patients have a kind of euphoria, and in advanced cases, dementia (dementia) is not uncommon. In about 85% of cases, multiple sclerosis is characterized by a remitting course, that is, periods of exacerbation are replaced by a significant improvement, and often the complete disappearance of all or individual signs of the disease. The duration of improvements can range from a few hours to several years. Especially good remissions are observed in the first years of the disease. However, after a few years, most patients become disabled to some extent. In the developed and irreversible stages of the disease, the combination of paresis with sataxia (staggering gait) is especially characteristic. The onset of the disease in many patients may be preceded by febrile illness, vaccination, trauma, surgery, pregnancy. 48. AIDS AIDS is an acquired immunodeficiency syndrome that is caused by the human immunodeficiency virus (HIV), so the disease has a double name: AIDS or HIV infection. The human immunodeficiency virus was isolated in 1983 by French and then American researchers. The detection of the virus in certain substrates associated with the diseased (blood, saliva, semen) made it possible to clarify the ways of transmission of the disease. In turn, the establishment of the etiology made it possible to develop work on the serological diagnosis of the infection. Thus, AIDS was clearly differentiated from other acquired immunodeficiencies. AIDS is a severe disease, with a far advanced disease, the death of the patient is almost inevitable. In terms of mortality, AIDS came in third after atherosclerosis and cancer. The human immunodeficiency virus belongs to the so-called retroviruses. Retroviruses are the only living creatures in the world that can synthesize DNA from RNA, while the rest can only synthesize RNA from DNA. For this purpose, the viruses of this group have the enzyme reverse transcriptase. Hence the name of the retrovirus (from Latin "retro" - "reverse"). This infection has a number of clinical and epidemiological features. These include: 1) an unusually (for the vast majority of infections) long incubation period (sometimes exceeding 5 years), so AIDS can be attributed to the so-called slow viral infections; 2) an exceptionally "narrow" application of the virus - it affects only some categories of immunocompetent cells, but this does not prevent the occurrence of a total defeat of the entire defense system of the body; 3) the infection does not have a definite clinical picture - its manifestations are determined by opportunistic conditions (i.e., adapting to certain conditions), the clinic of which is extremely diverse, which makes a purely clinical diagnosis of the disease impossible. Many features of the disease are currently not amenable to rational explanation. The origin of AIDS remains unclear. However, the mechanism of the impact of the AIDS virus on the body has already been sufficiently studied and the clinical manifestations of the disease in the advanced stage have been described. The main thing in the pathogenesis of HIV infection is the revealed ability of the virus to selectively turn off T-helpers, as a result of which the immune response does not develop, and the person becomes completely defenseless against any infection or pathology (it can even die from opportunistic bacteria). The virus, getting into T-helpers, can be in an inactive state for many years, but a person is already infected. When HIV for some reason becomes active, AIDS develops, most patients die within 1-2 years. 49. Diagnosis of AIDS Histological examination of the material shows the absence of granulomas as a characteristic sign of AIDS. Electron microscopy in biopsies of various tissues revealed multiple tubular-reticular inclusions in the cytoplasmic reticulum of endothelial cells, histocytes and lymphocytes. In preparations made from bronchial swabs, saliva, urine, gastric juice, pronounced cellular atypia, an increase in mature and immature lymphoreticular elements are found. In the bone marrow, a normal and somewhat increased number of nucleated cells is noted with a normal ratio of myeloid and erythrocyte cells, moderate plasmacytosis, and a slight increase in reticulin. The number of lymphocytes is reduced. In the bone marrow, there are histiocytes, many of which are absorbed by nuclear erythroid cells or granulocytes, which is similar to the virus-associated phagocytic syndrome described in patients with immune system dysfunction. In the lymph nodes - intense follicular hyperplasia, the size and shape of the follicles, cellular composition disorders similar to those in the blood, in particular, the predominance of T-suppressors. Thymus pathology in children with AIDS was studied. A sharp decrease in the number of lymphocytes and Hassal's bodies was noted. In those who died from the malignant course of AIDS, there was no division into the cortical and medulla in the thymus gland, Hassall's bodies and accumulations of epithelial cells were not detected. Thymus tissue was infiltrated with plasma and mast cells. Changes in the thymus in AIDS and congenital immunodeficiency are associated with damage to the T-system, but a thorough pathological and anatomical study makes it possible to clearly differentiate AIDS from congenital immunodeficiency. AIDS is characterized by a normal anatomical position and configuration of the thymus with normal blood vessels. The described changes in immunodeficiencies and one of the central organs of the immune system (thymus gland) lead to serious violations of its function. Delayed-type hypersensitivity reactions (to tuberculin, streptokinase, trichophytin) are sharply suppressed. The proliferative activity of lymphocytes when stimulated by their soluble antigens is reduced. At the same time, the level of immunoglobulins (JgM, JgJ, JgA) is increased. The presence of lymphocytotoxic antibodies in the blood serum of AIDS patients, which are combined with a deficiency of cellular immunity, has been established. AIDS patients lack the synthesis of interleukin-on-2. The production of interleukin-2 is inhibited by hypersecretion of prostaglandins. After the isolation of the causative agent of AIDS, the development of methods for determining antibodies to the virus, it was found that the number of people with antibodies to the pathogen significantly (about 50-100 times) exceeds the number of patients with clinically expressed AIDS. With regard to the ways of transmission of infection, there is no doubt that AIDS is transmitted by direct contact during sexual intercourse. Another way of transmitting the infection is considered to be the contact-household route - through objects contaminated with the blood of sources of infection, when the virus enters the body through small defects on the skin and mucous membranes. The possibility of "vertical" transmission of infection from virus-carrying mothers or patients is undoubted. 50. AIDS Clinic Characterizing the clinic of this serious and dangerous disease, there is reason to distinguish three main forms of infection: asymptomatic; an infection that proceeds according to the type of generalized lymphadenopathy and AIDS itself, when, in addition to the general symptoms characteristic of immunodeficiency, various opportunistic diseases occur with a predominant lesion of certain systems. The main feature of this infection is the duration of the incubation period. Without a doubt, AIDS is an infection with a very long incubation (from several months to several years). Early signs of AIDS are worsening symptoms of the previous period - the pre-AIDS period: 1) fever of unknown etiology with a course that is not amenable to conventional treatment; 2) lymphadenopathy; 3) increasing general weakness; 4) loss of appetite; 5) diarrhea; 6) weight loss; 7) enlargement of the liver and spleen; 8) cough; 9) leukopenia with possible addition of erythroblastopenia. Damage to the central nervous system occurs in about 1/3 of AIDS patients, and there are several main forms: 1) abscesses caused by toxoplasma; 2) progressive multifocal leukoencephalopathy; 3) cryptococcal meningitis, subacute encephalitis (usually cytomegalovirus etiology); 4) tumors, such as primary and secondary cerebral lymphomas; 5) vascular lesions (non-bacterial thrombotic endocarditis and cerebral hemorrhage associated with thrombocytopenia); 6) lesions of the central nervous system with focal brain damage with non-diffuse (self-limiting) meningitis. Another type of AIDS course is gastrointestinal, which is characterized by diarrhea and a significant decrease in body weight. The pathological process in the small and large intestines has a specific character. But these types of diseases are not limited to the pathologies of various systems observed in AIDS. The specificity of AIDS is such that specialists of various profiles have been studying this infection: virologists, immunologists, epidemiologists, parasitologists, dermatologists, and oncologists. There is an opinion among clinicians that in order to know AIDS, one must know all of medicine. In AIDS patients, the kidneys are affected, and glomerulonephritis with nephrotic syndrome is more common. Most patients with AIDS kidney disease quickly develop end-stage renal failure. 51. Pneumocystis pneumonia. Candidiasis. Cytomegalovirus infection The causative agent of Pneumocystis pneumonia is a protozoan pneumocystis, first described in 1909. This microorganism can cause interstitial pneumonia in premature and debilitated infants. The disease has a wide geographical distribution, but is quite rare. Extremely rarely, diseases occur in adults suffering from blood diseases, tumors, in persons treated with corticosteroids and immunosuppressants, during organ transplantation. Cases of generalized infection have been reported. With pneumocystis pneumonia, inflammatory infiltration of the interalveolar septa leads to the filling of the alveoli with a foamy mass, which reduces the respiratory surface of the lungs, causing a violation of gas exchange, oxygen deficiency. Clinically, the disease develops gradually; in some cases there may be an undulating course. In the beginning, shortness of breath, shortness of breath, and cyanosis appear. The temperature is often subfebrile. In the future, shortness of breath, rapid breathing, cyanosis progress, which are later joined by a dry, obsessive cough, respiratory acytosis, and pneumothorax may form. Cardiopulmonary insufficiency develops. The liver and spleen are enlarged. Pneumocystis pneumonia can be complicated by a bacterial infection. A presumptive diagnosis can be made on the basis of clinical, epidemiological data and a characteristic x-ray picture, the final one - on the basis of the detection of the pathogen in the mucus of the upper respiratory tract, as well as using an immunofluorescence reaction. This infection affects only people, it spreads by airborne droplets, as well as through dust. Pneumocystis pneumonia in AIDS patients often recurs and has an exclusively malignant course with a mortality rate of 90 to 100%, while usually this disease is relatively mild. Candidiasis This disease is caused by yeast-like fungi of the genus Candida. A clinically pronounced disease develops, as a rule, in violation of the functions of the protective system, which is primarily characteristic of AIDS. The most common localization of candidiasis in AIDS is the oral cavity, and especially the esophagus. There may also be skin candidiasis and a common form (up to 80%). Cytomegalovirus infection Caused by the virus of the same name. The name of the disease is associated with the mechanism of infection. Giant cells with characteristic intranuclear inclusions are formed in the affected tissues (from the Greek citos - "cell" and megalos - "large"). There may be changes in the lungs, gastrointestinal tract, and central nervous system. In the pulmonary form, interstitial pneumonia occurs, sometimes multiple cysts form in the lungs. In the gastrointestinal form, persistent diarrhea occurs with abdominal pain. There is ulcerative enteritis, sometimes pancreatitis. With the defeat of the central nervous system, a clinic of meningoencephalitis develops. In the absence of AIDS, cytomegalovirus infection affects only children. In AIDS, cytomegalovirus infection is found in 70% of patients. The malignant nature of this infection is usually noted. 52. Kaposi's sarcoma It was first described in 1872. It is also known under many other names (about 70 terms). Kaposi's sarcoma is a malignant neoplastic disease of the reticulohistiocytic system with a predominant skin lesion. According to the classification of skin tumors, Kaposi's sarcoma refers to malignant diseases from blood vessels - hemorrhagic hemangioendotheliomas. Clinically, in the normal course of the disease (not AIDS patients), skin lesions occur in the form of spots, plaques, nodes with foci of hemorrhage. The lesions are symmetrical. The size of the elements is up to 5 cm in diameter, the color is reddish-bluish, reddish-brown, later the color becomes darker. The elements are sharply limited from the surrounding skin, their surface is smooth with slight peeling. Pain is not felt. There is a gradual increase in size and number of elements, their grouping in the form of arcs and rings, followed by compaction, retraction of the center, the formation of plaques and tumor nodes 1-5 cm in size, hemispherical in shape, protruding above the skin surface. Possible ulceration of tumors. Kaposi's sarcoma is most often localized on the anterior surface of the lower leg, much less often on the auricles, abdomen, and penis. Sometimes elephantiasis of the extremities develops (severe swelling due to stagnation of the lymph), there is a sharp pain in the tumor-like formations, and a generalization of the process is noted with the formation of tumor nodes in the gastrointestinal tract, liver, lungs, lymph nodes and bones. Kaposi's sarcoma, not associated with AIDS (as an independent disease), in 3/4 cases has a long (6-10 years, less often - 15-20 years) course. Less often there is a subacute course (2-3 years); in some cases - an acute form with a rapid death of patients. Without an association with AIDS, Kaposi's sarcoma is a rare disease (0,06 per 100 population), although it has recently become much more active. As a rule, men over 000 years of age get sick. The highest incidence was observed in the indigenous population of Central Africa. There are European, African and North American variants of the disease. Kaposi's sarcoma, which occurs in AIDS patients, does not differ histologically from the usual one, but has a number of features. It primarily affects not the lower limbs, but is associated with the lymph nodes, mucous membranes and membranes of the internal organs. The disease acquires a disseminated malignant character. There may also be a lightning current. There is an opinion that Kaposi's sarcoma is an opportunistic disease in AIDS due to the fact that the AIDS virus induces oncogenesis by stimulating B-cell proliferation with a predominance of one clone. 53. Infections associated with herpes viruses Diseases caused by herpes simplex viruses (herpes simplex) and herpes zoster virus (herpes zoster) are less common in patients than diseases associated with cytomegalovirus. Of the two herpes viruses, opportunistic infections caused by the herpes simplex virus are more frequent. As a rule, with AIDS, these diseases are malignant. Interstitial pneumonia, chorioretinitis (eye damage), hepatitis, damage to the kidneys, brain, and endocrine glands develop. Herpes zoster infection is twice as rare. Herpes zoster, which occurs without a connection with AIDS, affects more often people over 60 years of age. With AIDS, this infection occurs in people aged 20-30 years. Opportunistic conditions in AIDS have a number of features. 1. Opportunistic pathogens often appear as pathogens, which under normal conditions do not cause pathological processes or cause them only in a certain contingent (small children, elderly people treated with hormones or irradiated). 2. Microorganisms that stay in the body for a long time and in its normal state do not cause pathology act as pathogens. 3. Opportunistic infections that complicate AIDS are characterized by a malignant course, a tendency to spread, duration, and high mortality. 4. Quite often, opportunistic infections recur, it is possible to change one infection to another, sometimes several opportunistic diseases occur simultaneously. All these features are due to the very pathogenesis of the disease - a sharp suppression of immunity. Features of the course of AIDS in children. Children make up a relatively small proportion of AIDS patients. They are mainly infected in utero, as well as during blood transfusions and the treatment of hemophilia. On average, the disease occurs 5 months after birth. In children with AIDS, prolonged fever, underdevelopment, hypergammaglobulinemia and impaired cellular immunity were noted. Opportunistic infections are dominated by pneumocystis and cytomegalovirus pneumonia, salmonella sepsis. In some sick children, several forms of infections and pathologies are observed simultaneously, caused by different etiological factors. Kaposi's sarcoma in children with AIDS is very rare. At the same time, infections caused by bacterial microflora are found in children more often than in adult patients. In children under one year of age, diarrhea is especially common. 54. Allergy The term "allergy" refers to the increased sensitivity of the body to the action of certain substances of the external and internal environment. Substances that can cause this hypersensitivity are called allergens. Allergens, like antigens, cause the formation of antibodies in the body. Allergic reactions are characterized by: 1) the allergen and the antibody combine on the cytoplasmic membrane of the target cell; 2) as a result of the action of the allergen-antibody complex on certain cells (mast cells), chemically active substances (histamine, serotonin, bradykinin, etc.) are released, which initiate an allergic reaction; 3) chemically active substances that were formed in the second stage affect the body, causing damage to tissue cells and inflammation. Allergy is the subject of the study of immunology, which studies the inadequate response of the immune mechanism to the introduction of an antigen, leading to damage in the body. The increase in the number of allergic diseases is due to several reasons. First, the reduction or even complete elimination of epidemic diseases reduced human contact with strong allergens of their pathogens, which inhibited the reaction to predominantly weak environmental allergens. Secondly, the introduction of vaccines, sera and other substances of an antigenic nature causes increased sensitivity (sensitization) of organisms predisposed to this. Thirdly, the number of new chemicals that do not even occur in nature has increased dramatically. These substances include drugs, the uncontrolled intake of which causes a change in the reactivity of the body, affects the neuroendocrine system. Fourth, changing the conditions of lifestyle and nutrition. Violation of contact with nature, urban living conditions lead to the fact that the natural products of nature (plant pollen, dandruff, animal hair, etc.), which a person used to meet from the moment of birth, become alien, and uncontrolled chemicalization of agriculture leads to increase in the content of chemicals in food. Each class of immunoglobulins is designed to protect the body from certain groups of antigens, so it can be assumed that the immune system forms a new element of protection - reagins to fight unusual allergen antigens, since immunoglobulins of other classes do not cause a universal protective reaction with these antigens - inflammation, t i.e. the immune system undergoes evolution, adapting to new environmental conditions, strengthening the corresponding element of protection. The result of adaptation is the increased reactivity of individuals, caused by the individual characteristics of their immune system. 55. Types of allergens household allergens House dust plays the main role among them. This is a complex allergen in its composition, which includes dust particles (from clothes, bed linen, mattresses), fungi (in damp rooms), particles of domestic insects, bacteria (non-pathogenic staphylococci, etc.). The main allergens in house dust are mites and their waste products. They live in beds, pillows, where they feed on particles of human epidermis. When shaking the bed, ticks, their particles and excrement enter the respiratory tract. This type of tick is very widespread. Daphnia, which are included in the feed of aquarium fish, are highly allergenic. Household allergens most often cause allergic respiratory diseases. insect allergens These are allergens of venom of stingers, saliva of biting insects and particles of the body cover of insects. These allergens cause both local and general allergic reactions. People who are hypersensitive to one insect have the same hypersensitivity to other insects within the order and family, since they have common antigens. epidermal allergens This group includes dandruff, animal hair, bird feathers, fish scales. One particular allergen is horse dander. This type of allergen causes occupational allergies in vivarium workers, sheep breeders, poultry workers, horse breeders, and hairdressers. Manifested by rhinitis, bronchial asthma, urticaria. Drug allergens Almost any drug can lead to the development of drug allergies. Drugs or their metabolites are, as a rule, haptens and become full-fledged allergens only after binding to tissue proteins. The drug molecule has a site in which antibodies are formed, i.e. this site (and not the entire molecule as a whole) plays the role of an antigenic determinant. Pollen allergens Allergic diseases are not caused by pollen of all types of plants, but only rather small (no more than 35 microns in diameter), and also have a good volatile effect. Most often it is the pollen of various types of wind-pollinated plants. An allergy caused by plant pollen is called hay fever. The antigenic composition of pollen is quite complex and consists of several components. For example, ragweed pollen contains 5-10 antigens, and timothy pollen contains up to 7-15 antigenic components. food allergens Allergens can be many foods. But most often they are fish, meat (especially pork), eggs, milk, chocolate, wheat, beans, tomatoes. In addition, allergens can also be food additives that are included in products and are chemicals. These are antioxidants, dyes, aromatic and other substances. 56. Stages of allergy development By the nature of the mechanisms that are involved in the development of allergies, stage IV is distinguished. I - immunological stage. It covers all changes in the immune system that occur from the moment the allergen enters the body, the formation of antibodies and sensitized lymphocytes and their connection with the allergen that has repeatedly entered or exists in the body. II - pathochemical stage. At this stage, biologically active mediators are formed. Mediators are formed when the allergen is combined with antibodies or sensitized lymphocytes at the end of the immunological stage. III - pathophysiological stage, or stage of clinical manifestations. It is characterized by the fact that the resulting mediators have a pathogenic effect on the cells, organs and tissues of the body. There are several types of tissue damage in allergic reactions: 1) reaginic type of tissue damage. 2) cytotoxic type of tissue damage. 3) damage by immune complexes. 4) an allergic reaction of a delayed type. The main mediators of type IV allergic reactions are lymphokines, which are macromolecular substances of a polypeptide, protein or glycoprotein nature, formed during the interaction of T- and B-lymphocytes with allergens. Lymphokines act on various cells (macrophages, lymphocytes, fibroblasts, epithelial cells, etc.) through the corresponding receptors on these cells. The most studied lymphokines are the following: 1) a factor that inhibits the migration of macrophages. 2) a factor that stimulates the formation of endogenous pyrogens. 3) mitogenic factors. 4) chemotactic factors. 5) lymphotoxins. 6) interferon is secreted by lymphocytes under the influence of a specific allergen (the so-called immune interferon) and nonspecific mitogens. 7) skin-reactive factor. Having considered the types of allergic reactions, the following conclusion should be made. The inclusion of one or another type of allergic reaction is determined by many factors, but they can be reduced to two main ones. These are the properties of the antigen and the reactivity of the organism. Insoluble allergens (bacteria, fungal spores, etc.) often lead to a delayed-type allergic reaction. Soluble allergens (antitoxic serums, g-globulins, bacterial lysis products, etc.), especially in large quantities, usually cause an allergic reaction of the immunocomplex type. Author: Anokhina N.V.
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