Medicines, correcting the processes of immunity

Recently, much attention has been paid to the development and study of specific agents that stimulate or suppress (modulate) the immune responses of the body.
It became obvious that the positive effect of different drugs can be explained by their ability to increase the overall resistance of the body or its nonspecific immunity, and also to influence specific immune responses.
The increase in the general resistance of the organism can be observed, for example, under the influence of a number of stimulant drugs (caffeine, eleutherococcus, etc.), vitamins (retinol, ascorbic acid, B vitamins, etc.). The ability of dibazol to stimulate immune processes was first shown by NV Lazarev. He also found stimulation of immune processes with pyrimidine derivatives (methyluracil, pentoxyl). Methyluracil and pentoxyl also stimulate regeneration processes, in particular leukopoiesis.
The ability to stimulate the immune reactions of the body (including leukopoiesis) has nucleic acid derivatives, as well as biogenic preparations (see Splenin, Ceruloplasmin, Enkad, etc.).
Among the agents that can stimulate immune processes and specifically activate immunocompetent cells (T and B lymphocytes), as well as additional immunity factors (macrophages, etc.), there are a number of preparations of microbial and yeast origin: prodigiosan, pyrogenal, etc.
The ability of these drugs to increase the overall resistance of the organism, to accelerate the regeneration processes served as the basis for their wide application in the complex therapy of infectious and infectious-inflammatory diseases, with the sluggish current regeneration processes and a number of other diseases.
Especially important in recent years is the study of the immunological properties of endogenous compounds formed by the body itself (lymphokines).
These compounds mobilize the body's immune forces to combat pathological processes. One of the most important endogenous immunostimulants are interferons (see Interferon). The therapeutic effectiveness of a number of drugs (see Prodigiozan, Poludan, Arbidol, etc.) is explained to a certain extent by the fact that they stimulate the formation of endogenous interferon, that is, they are K interferonogens.
The main role in the functioning of cellular and humoral immunity is played by thymus gland (thymus). It differentiates stem cells into lymphocytes, as well as the secretion of specific substances (hormones) that affect the development and maturation of certain cells of lymphoid tissue. Of the thymus extracts, a number of hormones, mainly polypeptides (thymosin, homeostatic thymus hormone, thymopoietin I and II, thymic humoral factor) and a compound of the steroid structure (timosterol) have been isolated and characterized.
Domestic scientists from the thymus gland received a number of extractive preparations (see Timalin, Taktivin, Timotin, Vilozen), proposed for use as immunostimulating agents. To some extent, they contain the listed hormonal substances, including Aa-thymosin, and are largely close to each other in action. From another organ of the immune system - bone marrow - a preparation of B-activin has been obtained (see Myelopid).
Of synthetic immunostimulants, levamisole is widely known (see). Other synthetic immunomodulating agents were also obtained.
Preparations, stimulating immune processes, began to find wide application in medicine.
At the same time, immunosuppressive (immunosuppressive) drugs also have important medical significance. Under certain conditions, immune mechanisms, which play an important role in protecting the body from various harmful effects, can cause unwanted reactions. Thus, the rejection of transplanted tissues and organs is associated with immunological incompatibility. With tissue incompatibility, the body produces antibodies to foreign antigen antibodies, which together with lymphoid cells cause its damage and death. There are also data that some diseases (systemic lupus erythematosus, thrombocytopenic purpura, nodular periarteritis, autoimmune glomerulonephritis, ulcerative colitis, rheumatism, etc.) can be considered as autoimmune processes that result from the release of specific antigens contained in the body. Under normal conditions, these antigens are in a bound state and do not cause immunopathological reactions.
In connection with these reasons, a new direction has been developed for the search for drugs that inhibit immunogenesis, which suppress the production of antibodies.
Because antibodies are produced by lymphocytes and plasma cells, various chemical compounds that suppress proliferative processes in lymphoid (immunocompetent) tissues and depressing biosynthesis of nucleic acids can act as immunosuppressive agents.
Immunodepressive activity is possessed by substances of various pharmacological groups, including corticotropin, glucocorticosteroids, etc. Cytostatic substances, preparations used as antitumor agents (cyclophosphamide, chlorobutin, thiophosphamide, prospidin, etc.), are particularly strong immunosuppressive activity, antimetabolites (6-mercaptopurine, 5-fluorouracil, etc.), some antibiotics (actinomycin, etc.) and other substances. Preparations of these groups are currently used as immunosuppressants. A special immunosuppressive drug is azathioprine, which is similar in structure and action to the cytostatic drug (antimetabolite) 6-mercaptopurine.
One of the most active immunosuppressants found in recent years to suppress the incompatibility reaction in organ transplants is K cyclosporin.