RHEUMATOID FACTOR, COMPLEMENT, AND CONGLUTININ ABERRATIONS IN PATIENTS WITH SUBACUTE BACTERIAL ENDOCARDITIS*

Abstract

Fifty-one patients were studied with subacute bacterial endocarditis. Of these patients 50% showed varying amounts of rheumatoid factors, 19% showing positive sheep cell tests. Extremely high titers of rheumatoid factor were present in several patients with endocarditis existing 5-8 months prior to diagnosis. The majority of patients showing rheumatoid factors during active bacterial endocarditis had Streptococcus viridans as infecting organism. Rheumatoid factors in endocarditis sera were shown to be 19S by density gradient ultracentrifugation and to react as direct agglutinators in the Gm system of Grubb. Serial precipitin curves, using heated and aggregated gamma-globulin as antigen, showed marked falls in quantity of rheumatoid factor 4-6 weeks after initiation of treatment. Sensitized sheep cell tests and latex reactivity likewise revealed rapid decrease in titer within several months after antibiotic therapy had been begun. The rapid fall in rheumatoid factor activity during therapy of subacute bacterial endocarditis is contrasted with relative constancy of levels in patients with rheumatoid arthritis. It is suggested that an unknown stimulus in rheumatoid arthritis is responsible for persistence of rheumatoid factor in rheumatoid arthritis.