The true autoimmune diseases are such diseases in which pathogenesis the lymphocytes, triggering destruction mechanisms, recognize the native molecules of the self cell membranes or intercellular substance and initiate an immune inflammation.
• Frequently and by mistake all pathologies with tissues defects mediated by immune mechanisms are referred to autoimmune processes. It is not quite true since any immune response against foreign pathogenic Ag is not developed without self tissues' damaging. If a pathogen penetrates into internal medium it tightly interacts with the cells and intercellular substance. With a pathogen destruction the immune system destructs the self environmental tissues, to the extent mediated by Ag dose.
• When a virus infects a cell either CTL or NK recognize viral Ag and entirely destroy the cell. If microbial products are absorbed on intercellular matrix or vessel wall or erythrocytes the antimicrobial AB with complement will induce matrix destruction, vascular wall inflammation (vasculi-tis), and hemolysis. The described events are not autoimmune since both CTL and AB target to microbial Ag, and tissues are destructed only due to tight connection between microbial products and the tissues.
• Another external source of increased self tissue alteration by immune mechanisms is the following. Chemical (sometimes natural) substances (drugs, food supplements, factors of chemical production process, and other negative factors of the kind) penetrate into the internal medium of the organism and really denaturate its molecules thus modifying them into target Ag which irritate immune system. In these cases the self tissues' alternations by immune mechanisms are incorrectly referred to autoimmune process, since the immune system fights against the external damages on the self tissue surfaces. Therefore a treatment will be pathogenet-ic, first of all, directed to the external damaging factors elimination, but not to self immune system suppression, making it indifferent to foreign factors presence on the organism cells. Anyway the clinical cases occur when the inflammatory immune process goes too far and it is necessary to inhibit it in the first turn.