RESUMO
We show that for the system of SH-containing compounds of the organism (cysteine, in particular) there are conditions leading to immunosuppression, which occurs when the level of amino acid cysteine in blood serum increases. The arising "overload" of free sulfhydryl groups inactivates antibodies of the IgM class of any specificity restoring disulphide intramolecular bonds and then the number of immune antibody-producing cells, mitotic activity of T- and B-lymphocytes and interleukin-2 synthesis are lowered and the mobility of surface immunoglobulin B lymphocytes receptors is damaged. Determination of total blood sulfhydryl groups for diagnostics of developing immunodeficiency disorder is not informative because of the high individual fluctuation of blood sulfhydryl groups number. It is the determination of inhibitory properties of blood serum regarding to IgM antibodies of any class and specificity in test system in vitro that is informative. It is proved clinically and by experiments that in the course of infectious inflammatory process the long-lasting inhibitory properties of blood serum are unfavorable and lead to the lingering course of disease. On the contrary, in case of autoimmune pathology the appearance of inhibitory properties of blood serum is a favorable prognostic factor.
