Diseases of the immune system include pathological conditions that develop against the background of changes in the effector mechanisms of immunity. Diseases of the immune system are classified taking into account the activity of immune reactions: in the case of hyperreaction to external allergens, allergic diseases develop, with a perverted reaction to their own (endogenous) tissue antigens, autoimmune diseases.
When the immune system is hyperactive, immunodeficiency conditions occur, in which the body becomes vulnerable to various kinds of infections. The main organs of the immune system are the bone marrow, thymus, spleen, tonsils, lymph nodes, and lymphoid tissue of the mucous membranes.
Doctors of various specialties are engaged in the diagnosis and treatment of this category of diseases: allergic pathology and immune insufficiency are in the field of view of allergologists-immunologists, autoimmune diseases (depending on the leading syndrome) are in the competence of specialists-rheumatologists, endocrinologists, neurologists, gastroenterologists, cardiologists, etc.
At the same time, there is a close relationship in the occurrence of allergic, immunodeficiency and autoimmune pathology. For example, with a deficiency of secretory immunoglobulin A, chronic infectious skin lesions may initially develop, further complicated by autoimmune diseases (dermatomyositis, rheumatoid arthritis, SLE and bronchial asthma.
Diseases of the immune system, in which a state of immunodeficiency develops, can be primary – congenital or hereditary and secondary – acquired.
The first group includes agammaglobulinemia, lymphocytic dysgenesis, Louis-Bar syndrome, Wiskott–Aldrich syndrome, etc. Secondary immunodeficiency can develop against the background of infectious, lymphoproliferative, metabolic diseases, intoxication, radiation, taking medications (immunosuppressants, corticosteroids). They may damage the cellular and/or humoral link of immunity, the phagocytosis system. The most well-known form of secondary immunodeficiency is AIDS (HIV infection).
Common manifestations accompanying various immunodeficiencies are recurrent infections – pneumonia, urinary tract infections, meningitis, generalized candidiasis, herpes, furunculosis, etc. Immunodeficiency conditions are often combined with allergic diseases – eczema, Quincke’s edema.
To date, it has been proven that birth defects or acquired deficiency of any immune factors play a leading role in the development of many oncological diseases. Patients with severe immune insufficiency often die from opportunistic infections.
To detect or confirm immunodeficiency, a special laboratory study of the immune status is necessary: determination of the number and morphology of lymphocytes, the content of immunoglobulins in the blood serum, the study of the complement system, the determination of specific antibodies, etc.
A lymph node biopsy, chest X-ray, ultrasound of the thymus and spleen may be indicated. Treatment of diseases of the immune system occurring with immunological insufficiency involves substitution therapy (administration of immunoglobulins, serums, bone marrow transplantation), immunocorrection, immunomodulation.
Autoimmune disorders constitute a special category of diseases of the immune system. In this group of diseases, the cells of the immune system exhibit autoaggression against the tissues of their own body. The prevalence of autoimmune diseases is extremely high – about 5-7% of the world’s population suffers from them.
Diseases of the immune system with an autoallergic mechanism are divided into organ-specific – in which autoantibodies are directed against a specific target organ (autoimmune gastritis, autoimmune thyroiditis, autoimmune hepatitis, etc.), non–organ-specific – in this case, autoantibodies can attack different organs and tissues (scleroderma, SLE, rheumatoid arthritis, etc.) and mixed.
Triggers triggering a cascade of immunopathological reactions can be bacterial and viral infections, radiation exposure, medicinal and toxic substances, stress. A number of autoimmune diseases are caused by hereditary factors.
Many diseases of the immune system of this group are characterized by joint and muscle pain, skin rash, weight gain or loss, fatigue, increased bleeding or a tendency to thrombosis, fever, muscle weakness. Most autoimmune diseases have a steadily progressive course, and without appropriate treatment they can lead to severe disability.
The most valuable methods of diagnosing autoimmune diseases are laboratory studies aimed at detecting autoantibodies to various tissues in the blood, circulating immune complexes, acute phase proteins, components of the complement system, genetic markers.
Since many antibodies are not specific to a particular pathology, but are detected in a number of diseases of the immune system, laboratory diagnostics is always supplemented by instrumental methods (radiography, ultrasound, endoscopy, scintigraphy, biopsy, etc.). In recent years, significant progress has been made in the treatment of diseases of the immune system.
The traditional approach includes immunosuppressive therapy, anti-inflammatory therapy with corticosteroids, efferent therapy (hemodialysis, plasmapheresis, hemosorption). According to the indications, surgical treatment is performed (splenectomy for hemolytic anemia, pericardectomy for autoimmune pericarditis, thyroidectomy for autoimmune thyroiditis, etc.). The transplantation of CD34+ autologous hematopoietic stem cells opens up very promising prospects.
The section “Immune diseases” of the handbook “Medic Journal” contains a detailed list of immunodeficiency and autoimmune pathologies. After reading them, the reader will receive comprehensive information about the causes, course, modern possibilities of diagnosis and treatment of diseases.