[Possible role of immune-phenomena in the pathogenesis of rheumatoid arthritis (author's transl)]

The R.A. is accompanied by a variety of different immune-phenomena. These are not restricted to the well known and diagnostically exploited IgM-rheumatoid factors in serum, but involve also rheumatoid factors of the Ig-classes G and A, which, at least partially are produced by lymphoid cells, which infiltrate the synovial membranes. These cellular infiltrations consist of macrophages, B and T lymphocytes, the latter being in excess. There is now good evidence that locally deposited, complement activating immune-complexes participate in the inflammatory lesions of the R.A.-joints by inducing the release of hydrolases from phagocytic cells. This event is also mediated by lymphokines and complement factors. Is is suggested that the pathogenicity of the immunoreactions occuring within the synovial tissue and fluid is a quantitative rather than a qualitative problem. In contrast to other tissues, the anatomy of the joint may favour the local accumulation of the immune-complexes. Moreover abundant immuno-reactions may be provided by a defective T-cell mediated control. Thus there is strong indication that immune-phenomena play an important role in the pathogenesis of R.A. This does not exclude the significance of metaboltic disturbances of the connective tissues for this disease.