Indicators of the state of immunity

Frequent repeated respiratory diseases require a special immunological blood test. The identified changes in the state of immunity, the doctor evaluates not in isolation, but in combination with the characteristics of the human condition and data from other laboratory and instrumental studies.

humor- liquid, moisture, bodily fluid. Such fluids include blood, lymph, saliva, etc.

Stages of immunological diagnostics:

• first. They reveal generalized characteristics or “gross” defects in the immune system. These studies are carried out using the simplest, so-called indicative, methods. Sometimes they are called immunological tests of the first level. Typically, these methods determine 20 indicators, among which quantity leukocytes, lymphocytes, various subgroups of T-lymphocytes, levels of immunoglobulins A, M, G, concentration of circulating immune complexes, etc.
• second. A more thorough analysis of the state of immunity is carried out at the second stage of the examination, if deviations were found in the indicative tests. the second level allows you to detect changes in the content of complex substances that are involved in the regulation of the immune response (for example, interleukin), as well as the number of cells that carry a certain type of immunoglobulin. According to indications, tests are carried out to assess antiviral, antitumor and transplant immunity.

An optimal immune response is achieved only when the humoral and cellular components of immunity interact.

Reasons for a decrease in the level of immunoglobulins:

• synthesis disorder one, several or even all classes of these proteins,
• increase in destruction (decay) immunoglobulins. In a number of conditions, significant losses of immunoglobulins occur, for example, in kidney diseases with the release of large amounts of protein in the urine (with nephrotic syndrome).

Causes of an increase in the level of immunoglobulins:

• enhancing their synthesis,
• decrease in the intensity of decay. Increased production of immunoglobulins is the cause of an increase in the concentration of the gamma fraction of globulin proteins in blood tests.

More often in an immunological study, the content of immunoglobulins of classes is determined. A, M, G, according to special indications - immunoglobulin E.

Features of class A immunoglobulins (IgA):

• include two types of proteins: whey(found in serum) and secretory(S IgA is found in secrets - in milk, saliva, lacrimal fluid, secrets of the intestinal and respiratory tract).
• produced by mucosal lymphocytes response to local influence foreign agent,
• protect mucous membranes from germs and allergens. By binding to microorganisms, IgA antibodies inhibit their adhesion to the cell surface and prevent penetration into the internal environment of the body. It is due to this mechanism that the development of chronic local inflammation is prevented. Local production of IgA provides a level of local immunity.
• in the internal environment of the body antibodies of this class able to neutralize bacteria and viruses.

Causes of a decrease in the concentration of IgA:

• acute,
• physiological decrease in children aged 3 to 5 months of life,
• congenital deficiency of IgA,
• diseases with signs of depletion of the immune system (removal of the spleen, tumors, intestinal or kidney protein losses, etc.).

Features of class G immunoglobulins (Ig Ji):

• main component gamma globulin fraction blood serum. They make up 80% of all human immunoglobulins.
• antibodies against bacteria, their toxins, viruses and other antigens,
• contained not only in the vascular bed, but also easily penetrate tissue near the vessels and there they carry out their protective function.
• are the main protective factor in the child's first weeks of life, as they are able to penetrate the placental barrier into the fetal blood serum. antibodies from milk through the intestinal mucosa of the newborn penetrate into his blood.

Reasons for a decrease in the concentration of IgG:

• chronic infections,
• exposure to ionizing radiation,
• taking drugs that inhibit cell division,
• congenital immunodeficiency diseases.

Reasons for increasing the concentration of immunoglobulins:

Activity metrics the work of “eater” cells (phagos - to eat, devour) bacteria and other agents are as follows: phagocytic number(normally, a cell absorbs 5-10 microbial particles), phagocytic capacity of blood, phagocytic index, number of active phagocytes, phagocytosis completion index(should be >1.0).
A decrease in the phagocytic activity of blood cells leads to a chronic course of the inflammatory process against the body's own tissues (autoimmune processes). When phagocytosis is inhibited, the destruction and excretion of immune complexes from the body is disrupted.

Lysozyme is an antibacterial enzyme that is able to dissolve the shell of gram-positive microorganisms and cause their death (lysis). Lysozyme is produced by blood cells. Its normal content in the blood is from 7 to 14 mcg / l. When exposed to gram-negative bacteria, lysozyme needs “support” of another factor of natural immunity - the complement system.

Complement system consists of nine complex biochemical compounds, which are called components. By changing the concentration of any of them, the immunologist judges the place of a possible breakdown in the link of immunity.
In some immunological laboratories, the indicator of the work of the cytokine system is also determined. This is a relatively new concept for parents. Cytokines are protein molecules with a small molecular weight. It is to this group of substances that are more familiar to everyone interferons. The main organ in which cytokines are cleared is the liver. In various liver diseases, there is an increase in the blood levels of substances of this class and an aggravation of the severity of the course of diseases.

Thus, immunity is a very complex, multicomponent and multilevel system. In the operation of this system, there must be a clear and strict sequence of all reactions. Only in this case, the immune system protects the body from foreign agents.

Analysis of immunity indicators in children should be carried out in the dynamics of the disease. Of paramount importance are indicators of the ratio of various links of immunity, and not isolated indicators. When changes in the immune state are detected, the immunologist conducts special blood tests to assess the ability of blood cells to various stimuli.

Immunological studies are indispensable for the selection of a specific drug for the treatment of frequently ill children.