Antibody to ribonucleoprotein in pauciarticular juvenile rheumatoid arthritis.

Sera from 8 children with pauciarticular juvenile rheumatoid arthritis (JRA) were studied to determine the nuclear antigen to which antinuclear antibody (ANA) is directed. No patient had antibody to native DNA, nuclear histones, or saline soluble nuclear antigens. Trypsin treatment of the nuclear substrate abrogated ANA staining for all sera tested, while RNase treatment abrogated ANA activity for 6 of 8 sera. These results indicate that ANA in most patients with pauciarticular JRA is directed to a ribonucleoprotein that requires both RNA and protein moieties for antigenic integrity.