Association of Antibodies to Ribonucleoprotein and Sm Antigens with Mixed Connective-Tissue Disease, Systemic Lupus Erythematosus and Other Rheumatic Diseases

Abstract
Extractable nuclear antigen contains ribonuclease-sensitive (ribonucleoprotein) and ribonuclease-resistant (Sm) components. To determine the diagnostic usefulness of antibodies to these antigens, a multicenter study was undertaken in which serums were analyzed for these antibodies and the findings compared with clinical and other laboratory characteristics of the patients.