Abstract
Antibodies to ribonucleoprotein (RNP) were detected by an immunofluorescence technique based on the sensitivity of speckled antinuclear antibodies to ribonuclease. These antibodies were found to identify a group of patients with a consistent set of clinical features, especially arthritis, swollen hands, Raynaud's phenomenon, and myositis. The presence of anti-RNP antibodies in sera from patients with polymyositis, systemic lupus erythematosus, and systemic sclerosis was also associated with these clinical features. Other studies of the clinical significance of these antibodies support the concept that they appear to identify a group of patients with a distinct clinical condition.