OLIGOCLONAL IMMUNOGLOBULINS AND SMOOTH-MUSCLE ANTIBODIES IN ARTHRITIC JOINTS

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 40  (1) , 103-110
Abstract
In 12 synovial fluid/serum pairs from patients with various types of seronegative polyarthritis, homogeneous .gamma.-ban by agarose gel electrophoresis were found in 7 of the synovial fluids and in only 1 of the sera. In 6 of the fluids with .gamma.-bands, smooth muscle antibodies (SMA) were also present, usually in a titer identical to that in serum. In fluids with no .gamma.-bands, no SMA were detected. In 40 synovial fluid/serum pairs from patients with seropositive rheumatoid arthritis, no .gamma.-bands were detected in the synovial fluids, and SMA were present in only 3 pairs. Absorption and inhibition experiments did not give evidence that the SMA activity in seronegative polyarthritis was confined to the .gamma.-bands in the synovial fluids. The SMA activiy in the fluids seemed to be directed against actin and non-actin muscular antigens. The association between locally produced oligoclonal immunoglobulins and possible locally produced SMA with different electrophoretic mobility suggests that in some of these patients there is a local synovial production of oligoclonal antibodies with different specificities. Thus, even if the results may indicate a local virus infection in some arthritic joints, they may also be due to an unspecific local stimulation of B [bone marrow-derived] cells or to a specific antigen stimulation combined with an unspecific co-activation of other antibody-producing cells.