Ssb La Antibodies Elisa Blood

Sjogren syndrome type A antigen (also known as SS-A, Ro, and E3 ubiquitin-protein ligase TRIM21) and Sjogren syndrome type B antigen (also known as SS-B and Lupus La protein) are nuclear antigens to which autoantibodies develop in autoimmune disorders such as Sjogren’s syndrome (SS) and systemic lupus erythematosus (SLE). Between 40 and 70% of patients with SS have anti-SSA and/or anti-SSB autoantibodies, and 30-40% and 10-15% of patients with SLE are anti-SSA and anti-SSB positive, respectively. Longitudinal studies have shown that anti-SSA and -SSB antibodies may be present up to 20 years before the clinical onset of disease. SS patients who are anti-SSA and anti-SSB positive may have longer disease duration, parotid gland enlargement, decreased salivary flow, more severe minor salivary gland infiltration and a higher prevalence of extraglandular manifestations.

SS-B/La is an extractable nuclear antigen (ENA) composed of a 48-kD protein combined with RNA species. SS-B/La antibodies are found primarily in patients with Sjogren syndrome or lupus erythematosus (LE), where they occur with frequencies of approximately 60% and 15%, respectively.(1,2) SS-B/La antibodies occur only infrequently in the absence of SS-A/Ro antibodies.

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. Each ENA is composed of 1 or more proteins associated with cytoplasmic or small nuclear RNA species (snRNP) 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.