Rheumatoid factor in synovial effusions: local production and consumption

Abstract

The ratio of synovial fluid γM-type rheumatoid factor (RF) to serum RF was compared with the ratio for two other γM-antibodies (trypsin- and periodate agglutinin) and total γM-globulin content in thirteen patients with rheumatoid arthritis.

In one case, the ratio for RF was higher than the ratios for the other γM-globulins and declined after synovectomy, indicating that a significant amount of RF in the synovial fluid was derived from locally produced RF. In three cases, the ratio for RF was lower than the other γM-globulin ratios, indicating local consumption or inhibition of RF in the joint. It was postulated that this phenomenon was due to some form of aggregated γG-globulin. In nine cases, the ratio for RF was equal or almost equal to the ratios for the other γM-globulins, indicating that the synovial fluid RF in these cases was mainly delivered from the circulation.