[Mycoplasma arthritis in man and mechanisms of its pathogenesis].

Possible etiologic contribution of mycoplasma to human rheumatoid arthritis (RA) is supported by their recovery from synovial fluid of RA patients, as well as Mycoplasma antigens and antibodies detection in the bloodstream. The detectability of free antigens of M. arthritidis (Ma) and M. fermentans (Mf) in the sera of patients was 22.4%, and that of antibodies against those, 52.7%. Considerable difference between the detectability of Mycoplasma antigens and antibodies can be attributed to the fact that the bulk of the antigens form part of immune complexes and cannot be detected by serologic tests. Mitogenic effect of arthritogenic Mycoplasma and their ability to produce a cytotoxic effect on various cells, including lymphocytes, appears to be a mechanism of immune process developing in association with human RA. A study of immunobiological properties of individual Ma and Mf cell components has shown that a protein factor translocated into the culture medium is responsible for mitogenic action. Ma cytotoxicity in respect of target cells is related to its cytoplasmatic membrane. Mf produces a factor, acting directly on rat lymphocytes; its synthesis is apparently taking place on the cell membrane.