Autoantibodies to triiodothyronine and thyroxine in primary hypothyreosis.

The role of autoantibodies to triiodothyronine and thyroxine hormones is still obscure. Our investigation of autoantibodies in primary hypothyreosis gave controversial results. We have investigated 40 patients with primary hypothyreosis caused by chronic atrophic thyroiditis and lymphocytic Hashimoto thyroiditis. We have examined autoantibodies to triiodothyronine (T3) and thyroxine (T4) in patients prior to and during substitution therapy. The control group of 50 subjects with no signs of thyroid gland disease were also examined. Positive antibodies to their own T3 or T4 hormones were not found in this group. Out of 40 patients with primary hypothyreosis, autoantibodies to their own hormones were found in 11 patients (27.5%). At the same time, antibodies to T3 and T4 were found in 3 patients, antibodies to T3 in 7 and antibodies to T4 were found in only 1 patient. In the course of substitution therapy (L-thyroxine) there was an increase in number of patients with antibodies to T4, thus having no statistical significance in comparison with the total number of patients with positive antibodies to T3 and T4.