Description
Systemic autoimmune disease is characterized by the presence of circulating auto-antibodies directed to a wide variety of cellular antigens. Systemic lupus erythematosis (SLE), commonly referred to as Lupus is the best known of these diseases. Other possible connective tissue diseases include mixed connective tissue disease (MCTD), Sjogren syndrome, sclerodema, and polymyositis/dermatomyositis. The majority can be diagnosed by clinical presentation and their antibody profiles to the various antigens involved, which include dsDNA, SM, RNP, SSA, SSB, Scl-70, Jo1 and Histones. Therefore, immunoassays for autoantibodies are useful for diagnostic and prognostic evaluations of autoimmune disease. SSA (Ro) antigen (60kd) and 52 kd polypeptides complexed with Ro RNAs are detected in about 75% of primary and secondary Sjögren syndrome, In>90% of subacute cutaneous lupus and in the vasculitis-associated Sjögren syndrome, SS-A autoantibodies are present and are accompanied in ~50% by SS-B/La autoantibodies. The coexistence of SSA and SSB autoantibodies probably reflects the presence of these polypeptides on the same particle and the spreading among autoimmunity to these self antigens