Immunological reactivity to Mycoplasma fermentans in patients with rheumatoid arthritis. Preliminary communication.

There is conclusive evidence for an immune response in the synovial membrane of rheumatoid joints. Deposits of gamma globulin, for example, may be demonstrated, as may plasma cells producing gamma globulins and rheumatoid factors (Smiley, Sachs, and Ziff, 1968). Complement becomes fixed in the synovium and the complement level in the synovial fluid is decreased (Lundh, Hedberg, and Laurell, 1970). This may be interpreted as an immune response in the synovial tissue itself, that is, antigen (possibly a micro-organism) located in the joint, stimulating immunologically competent cells in the synovial membranes. In support of this may be cited the histology of the rheumatoid synovial membrane which shows the cellular infiltration to be characteristic of a cell-mediated hypersensitivity reaction.