Presence of aggregated gamma-G-globulin in certain rheumatoid synovial effusions.

Abstract

A precipitin reaction occurred between rheumatoid arthritis sera with high titre rheumatoid factor (RF) and certain rheumatoid synovial effusions. The precipitating factor in the sera was shown to be γM-type RF, reacting mainly with human γG-globulin. The precipitating component of synovial effusions was structurally altered, γG-globulin sedimenting much faster than native γG-globulin by density gradient ultracentrifugation. Following exposure to increasing hydrogen ion concentrations, an increasing amount of the RF-precipitating γG-globulin attained a slower sedimentation rate. Evidence for the in vivo presence of this altered γG-globulin was given, indicating that it may represent a stimulus for RF production.