Antibodies to Extractable Nuclear Antigens (ENA) in Rheumatoid Arthritis Assayed by ELISA: A Clinicopathological Correlation

Abstract

A Clinicopathological study of autoantibodies in the sera of 53 RA patients was performed. Antibodies to extractable nuclear antigens (ENA) were assayed by ELISA and were found in 42% of the subjects, all bound to RNAase sensitive ENA, and these antibodies were significantly associated with the presence of tendon nodules (p< 0.05). Antibodies to dsDNA were found in 16%, and rheumatoid factor (RF) was present in 81%; neither of these antibody groups were associated with any of the clinical abnormalities examined for. Comparisons between anti-ENA, anti-dsDNA and anti-immunoglobulin autoantibody parameters in RA subjects revealed ENA and dsDNA antibody levels to be significantly mutually related (p< 0.01) but both were independent of RF levels. We concluded that in RA, ENA antibodies constitute a unique autoantibody subset, that may result from an immune response to an autoantigen directly linked with the aetiopathogenesis of RA.