Autoantibodies in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease in which the predominant autoantibodies are antinuclear antibodies (ANA) reactive with DNA and histones, and antibodies reactive with the non-histone extractable nuclear antigens (ENA), Sm and Ro. Racial differences demonstrable in predisposition to SLE are also evident in the prevalence of autoantibodies, the frequency of anti-Sm and anti-Ro being 2-4 times higher in Asians with SLE than in Caucasians with SLE. Autoantibodies have also played a role in the classification of lupus and the recognition of multisystem autoimmune diseases that fail to meet the classical criteria for the identification of patients with SLE but appear to be variants of lupus. Anti-Ro is a diagnostic marker for subacute cutaneous lupus, anti-(U1)RNP a marker for mixed connective tissue disease, antibodies to phospholipids a marker for the syndrome comprising stroke, fetal wastage, thromboembolism and thrombocytopenia and antibodies to histones a marker for lupus induced by the drugs hydralazine and procainamide. There is still no unaminity on whether these antibodies play an integral role in the disease process or whether they are "epiphenomena". The challenge for research in the 1980s is the understanding of the relationship of these antibodies to the pathogenesis of SLE.