IGG RHEUMATOID-FACTOR IN SUB-ACUTE BACTERIAL-ENDOCARDITIS - RELATIONSHIP TO IGM RHEUMATOID-FACTOR AND CIRCULATING IMMUNE-COMPLEXES

Abstract

The levels and properties of Ig[immunoglobulin]G rheumatoid factor (IgG RF) and IgM rheumatoid factor (IgM RF) in patients with subacute bacterial endocarditis (SBE) were studied using a radioimmunoassay. The relationship of these autoantibodies to circulating immune complexes was also studied. Significantly elevated amounts of IgG RF and IgM RF in SBE sera were found. The IgG RF chromatographed on Sepharose 6B as an intermediate complex, indistinguishable from the pattern seen in rheumatoid arthritis. RF levels peaked later in the course of SBE than did levels of circulating immune complexes. With antibiotic treatment RF levels declined, although not as fast nor as completely as circulating immune complexes. IgG RF and IgM RF in SBE may be part of a polyvalent antibody response to elevated levels of circulating immune complexes which do not themselves contain RF.