From Big Medical Encyclopedia

IMMUNODEPRESSIVE STATES (Latin immunis the free, saved from something + depressio suppression) — the temporary or constant oppression of immune system developing under the influence of external impacts on an organism.

I.s. can develop as a result of the following influences: 1) surgical, caused by removal central (thymus gland) or peripheral (a spleen, limf, nodes) bodies of lymphoid system or removal recirculating through blood and a lymph of lymphocytes (hron, a drainage chest limf, a channel); 2) the physical, assuming general irradiation of an organism beams of X-ray, gamma-rays or other types ionizing radiation which causes development of an acute radial illness with sharp oppression immunol, reactivity of an organism; 3) chemical, based on use pharmakol, means — immunodepressants (see. Immunodepressive substances ), the relating hl. obr. to various classes of tsitostatik (the analogs of the purine and pirimidinovy bases alkylating connections, inhibitors of proteinaceous synthesis, corticosteroids and so forth); 4) the immunological, based on use immune anti-lymphocytic, antithymocyte or antiglobulinovy serums.

Syndrome typical for majority I.s., it is characterized by hypersensitivity to infections, engraftment on a long term of alien (allogenic) transplants and increase in frequency of developing of malignant tumors.

Laboratory indicators And. pages are a lymphopenia, reduction of indicators blastotransformation of lymphocytes (see) blood under the influence of phytohemagglutinin and other mitogens or in mikst-culture, decrease in rosetting ability, level of serumal immunoglobulins of three main classes — IgM, IgG, IgA (see. Immunoglobulins ), oppression of development of skin tests on hypersensitivity of the slowed-down type with tuberculine 2,4 dinitrobenzene chloride, etc.

And. pages drew attention of physicians in the first quarter of our century during the studying of a role of blockade of reticuloendothelial system on an infection and immunity, however the greatest interest arose in 60 — the 70th in connection with wide use of immunodepressants for prevention of rejection replaced. bodies, in particular kidneys and heart as allogenic transplantations without immunodeiressiya come to an end with graft rejection during the first 2 — 3 weeks (see. Transplantation ). Experience of transplantation of kidneys showed that the long immunosuppression is followed by easing not only antimicrobic protection, but also sharp increase in probability of developing of tumors. According to the International center registering results of renal transplantation by the beginning of 1974 more than 15 thousand renal transplantations were produced. In all cases the long immunosuppression by means of chemical drugs, anti-lymphocytic serums (ALS), a drainage of a chest channel, etc. was carried out. Frequency retikulo cellular sarcomas at these patients more than by 300 times exceeds the frequency of emergence of this type of tumors at the people who are not receiving immunodepressive therapy. The probability of emergence of lymphoma increases by 35 times. The most frequent infectious complications at And. pages are pneumonia and other diseases of respiratory system.

Features I.s., various influences developing later, are defined by the nature of influence of this or that impact on immune system and on functioning of its separate links.

On modern representations, all specific immunol, reactions are carried out by two types of lymphoid cells representing two cellular systems of immunity — timuszavisimy (T-system) and timusnezavisimy (V-system). T lymphocytes arise in a thymus (thymus gland) from polipotentny stem hemopoietic cells (see. Hemopoiesis ), occupy timuszavisimy zones limf, nodes; they make apprx. 80% of lymphocytes of a chest channel and apprx. 60% of lymphocytes of blood and carry out reactions of cellular immunity like the slowed-down giiyerchuvstvitelnost. For this reason the thymectomy, a drainage of a chest channel and use of ALS damaging the lymphocytes which are generally circulating in blood cause suppression of cellular forms immunol to a large extent. reactions, reactions of hypersensitivity slowed down ooze and transplant immunity.

The V-lymphocytes making the ground mass of lymphocytes of marrow and apprx. 60% of splenic lymphocytes after contact with antigen take a way of proliferation and a differentiation, turning into plasmocytes — producers of antibodies. As proliferation and a differentiation of cells are an indispensable condition of emergence of antiteloprodutsent, ionizing radiation, cytostatics and inhibitors of proteinaceous synthesis oppresses an antibody response. At the same time oppression of development of antibodies is usually more expressed, than oppression of cellular forms of reaction, including transplant immunity. In this regard in surgery at transplantation such cytostatics as an imuran and 6 Mercaptopurinum, combine with ALS and corticosteroids. The last destroy population of T lymphocytes to a large extent, in a smaller measure influencing proliferation and a differentiation of B-cells (see. Immunocompetent cells ).

The question of removal of an organism from a condition of an immune depression is especially important at treatment of an acute radial illness, at a cut most often the infectious complication arising owing to sharp suppression of immunity is a cause of death. The similar situation develops at poisoning with cytostatics, at congenital immunodeficiency disorders (see. Immunological insufficiency ) and at overdose of immunodepressive means. Prescription of antibiotics of a broad spectrum of activity, administration of drugs of immunoglobulin and keeping of the patient in the amicrobic room are obligatory. It is obvious that these actions in itself do not recover immunol, reactivity. Cancellation of immunodepressive influences (e.g., corticosteroids and ALS) quite often is sufficient for recovery. However a serious poisoning cytostatics (analogs of the bases nucleinic to - t, the alkylating connections) and total radiation defeats leads to so expressed «devastations» of the hemopoietic and lymphoid systems that spontaneous recovery of immune responsiveness does not happen. In these cases for a conclusion of an organism from And. the page is required substitution destroyed In - and T-systems of immunity in the way transplantations of marrow (see) or marrow together with cells of a thymus gland.

Transplantations of the cellular suspensions containing lymphoid elements (marrow, a spleen, lymph nodes, a thymus gland) demand special care at selection of the donor since antigenic compatibility in these cases shall be bilateral. Otherwise the replaced cells will develop reaction, pernicious for the recipient, «a transplant against the owner» (see. Incompatibility immunologicheky ). The most reliable indicators of removal of an organism from And. pages are reduction of a lymphopenia, increase in indicators of a blastotransformation of lymphocytes of blood and increase of level of serumal immunoglobulins.

Bibliography: Petrov R. V. Immunology and immunogenetics, M., 1976, bibliogr.; Petrov R. V. and Manko V. M. Immunodepressora, M., 1971, bibliogr.; Having consoled in B. S. and Babichev V. A. Inhibitors of biosynthesis of antibodies, M., 1974, bibliogr.; Hoover R. and. P of u m e-ni J.F. Risk of cancer in renal-transplant recipients, Lancet, v. 2, p. 55, 1973, bib liogr.; Schwartz R. S. Immunosuppression and neoplasia, Progr. Immunol., v. 5, p. 229, N. Y., 1974.

P. V. Petrov.