ANTIBODIES TO EXTRACTABLE NUCLEAR ANTIGENS IN RHEUMATOID-ARTHRITIS - RELATIONSHIP TO VASCULITIS AND CIRCULATING IMMUNE-COMPLEXES

Abstract

Antibodies to extractable nuclear antigens (ENA) were analyzed in the sera of 52 patients with severe rheumatoid arthritis (RA) who were divided into 2 categories: 25 with arthritis only and 27 with extra-articular disease. Using hemagglutination, counterimmunoelectrophoresis (CIE) and double diffusion, antibodies to ENA were detected in 3 (12%) of the patients with arthritis only. In the group with extra-articular disease, antibodies were found in 16 (59%) of the patients. In 10 patients the antibodies reacted with an RNase and DNAse resistant, but trypsin sensitive protein component of ENA. These patients all had extraarticular disease with digital vasculitis being a particularly common feature. Their sera also contained circulating immune complexes detected by elevated cryoprecipitate protein levels associated with relatively low complement levels. Antibodies to soluble proteins of nuclear origin may be markers of circulating immune complexes in extra-articular RA.