Antibodies against nuclear poly(A) polymerases in rheumatic autoimmune diseases

Sera from 53 patients, 26 with systemic lupus erythematosus (SLE), 8 with rheumatoid arthritis (RA), 9 with Sjogren's syndrome (SS), and 10 with scleroderma (Scl), were screened for the presence of antibodies against liver-type poly(A) polymerase and tumor-type poly(A) polymerase. Sixty percent of the patients with the above four autoimmune diseases have antibodies directed against liver poly(A) polymerase, whereas sera from 74% of the patients contained anti-hepatoma poly(A) polymerase antibodies. About 25% of the patients produced antibodies exclusively against the tumor poly(A) polymerase. IgG containing anti-liver or anti-tumor poly(A) polymerase antibodies inhibited the activity of the respective enzyme. IgG containing antibodies against liver and tumor enzymes inhibited the activity of both enzymes, whereas IgG from sera that did not react with poly(A) polymerase had no effect on either enzyme. These data demonstrated the specificity of these autoantibodies and confirmed the results of the radioimmunoassay.