Evaluation of the Ratio of T3 Release Stimulating Antibodies to TSH-Binding Inhibiting Antibodies during the Course of Graves' Disease

Summary

The mechanisms leading to a remission of Graves' hyperthyroidism are still unknown. One possibility would be that autoantibodies raised during the course of disease could change the composition of the autoantibody spectrum in such a way to counterbalance the action of stimulatory autoantibodies, thereby resulting in an induction of remission. Therefore, in the present study using a rigorous methodological approach we have characterized the portion of T3 release stimulating autoantibodies among the total body of TSH receptor antibodies, i. e. the TSAb/TBII ratio, over the course of a 12 month antithyroid therapy in 25 patients with Graves' hyperthyroidism. Further, we have evaluated the relation of the alteration of the antibody spectrum to the course of disease. The TSAb/TBII ratio was indeed found to be subject to considerable changes. The observed shift in the antibody composition was more often in favor of a relative increase in stimulatory inactive TBII. Nevertheless, the clinical course of patients showing a persistence of TBII despite the decline or even absence of TSAb proved to be variable. In conclusion, our data indicate that the spectrum of autoantibodies may change over the course of antithyroid therapy owing mostly to a relative rise in stimulatory less active autoantibodies. This phenomenon, however, is apparently not closely related to the course of disease.

Key words

Graves' Disease - Remission of Hyperthyroidism - TSH Receptor Antibodies - T3 - Release Stimulating Antibodies.