Enzyme-linked immunosorbent assay of autoantibodies reacting with thyroid plasma membrane antigens in sera of patients with autoimmune thyroid diseases.

A sensitive and specific enzyme-linked immunosorbent assay (ELISA) for the detection of autoantibodies reacting with thyroid plasma membrane antigens has been established. Autoantibodies reacting with thyroid plasma membrane antigens were detected by the ELISA in 95% of untreated hyperthyroid Graves', 68% of antithyroid drug-treated Graves' up to four months of the therapy, in 62% of Hashimoto's thyroiditis and in 8.9% of toxic nodular goitre. The ELISA was negative in 100% healthy blood donors, 100% non-toxic nodular goitre, in 12 patients with rheumatoid arthritis, 18 patients with scleroderma and 94% of patients with systemic lupus erythematosus. The mean value of autoantibodies titre was higher in untreated hyperthyroid Graves' (1:84,000) and lowest in positive patients with autoimmune disease of non-thyroid origin (1:4000). The cross-reactivity of antimicrosomal antigen antibodies was below 10%; there was no influence of antithyroglobulin antibodies on the ELISA; and most of the autoantibodies react with plasma membrane antigens different from the TSH binding sites.