Anti-SSA(Ro) antibody: a connective tissue disease marker.

The characteristics of 100 patients with anti-SSA(Ro) antibody were studied. By accepted criteria 34 patients had systemic lupus erythematosus, 25 had other known connective tissue diseases (CTD) and 9 had no significant evidence of a CTD. Thirty-two patients had an unclassified CTD characterized in most instances by arthritis, dermatitis, and a positive fluorescent antinuclear antibody test. The results support the concept of a continuous spectrum of autoimmune disease in which anti-SSA(Ro) antibody may be a marker and in which a variety of disorders may be found that cannot be classified by accepted criteria.