[Anti-microsomal, anti-thyroglobulin antibodies and thyroid stimulants in hyperthyroid subjects. Analysis of 315 patients followed-up for 3 years at a single medical center].

The objective of the study was to evaluate the significance of the determination of antithyroid antibodies in hyperthyroid patients. Two-hundred-fifteen untreated Graves' hyperthyroid patients (active toxic diffuse goiter-TDG), 54 Plummer's hyperthyroid patients (focal hyperthyroidism) and 46 subjects with other forms of hyperthyroidism were studied. Serum levels of T4, T3, TSH, TSH receptor antibody (TRAb), microsomal antibody (TMAb), and thyroglobulin antibody (TGAb) were evaluated before starting treatment, at regular intervals during therapy, and during the follow-up period after therapy was withdrawn. The antibodies were positive in all patients with active and non-active TGD but positive in only two patients (3.7%) with focal hyperthyroidism. During the treatment interval, TRAb, TMAb and TGAb serum levels fell with a nadir in the 7th month of therapy. In particular, TRAb fell to normal levels in all patients who had basal levels less than 500 U/l (97.7% of the cases) while TMAb and TGAb remained positive. Relapses, following the completion of therapy, occurred in 20.4% after one year and in 33% after two years. Relapses were always linked to a new increase in TRAb. In conclusion, TRAb can be useful in the determination of early disease and in diagnosing remission. It did not appear useful as a prognostic indicator for relapse in individual patients.