Clinical Information

SS-B/La is 1 of 4 autoantigens commonly referred to as extractable nuclear antigens (ENA). The other ENA are SS-A/Ro, RNP, and Sm (Smith). Each ENA is composed of 1 or more proteins associated with cytoplasmic or small nuclear RNA species (snRNA) ranging in size from 80 to 350 nucleotides. Antibodies to ENA are common in patients with connective tissue diseases (systemic rheumatic diseases) including LE, mixed connective tissue disease, Sjogren syndrome, scleroderma (systemic sclerosis), and polymyositis/dermatomyositis. A positive result for SS-B/La antibodies is consistent with connective tissue disease, including Sjogren syndrome and lupus erythematosus.