Fluctuations in the titers of anti-thyroid hormone and anti-thyroglobulin antibodies in 4 cases of Graves' disease during long-term treatment period

Abstract

We studied 4 cases of Graves' disease with anti-thyroid hormone antibodies. Changes in the serum levels of triiodothyronine(T3), thyroxine(T4), free T4, thyrotropin(TSH), and thyroglobulin(Tg), as well as titers of anti-Tg antibodies, anti-thyroid hormone antibodies, anti-TSH receptor antibodies(TRAb) and anti-microsomal antibodies(MCHA) during 2 10 years' treatment periods were examined in each case. Case 1; A woman, who was diagnosed as having Graves' disease when she was 10 years old, had been treated with methimazole(MMI) or propylthiouracil(PTU). Treatment with the antithyroid drug had been discontinued by herself when she was 19 years old until she was 24 years old, when she was pregnant and consulted our hospital. Since her serum levels of T3 were unusually high, examination of her serum for the presence of anti-T3 antibodies was done. The presence of anti-T3 antibodies in her serum was confirmed. Case 2; A woman, who was diagnosed as having Graves' disease at the age of 41, had been treated with MMI or PTU. Presence of serum anti-T3 antibodies was found in a screening test for the antibodies. Serial sera were obtained during the 5 year observation period when she was treated with MMI, PTU, and subtotal thyroidectomy. Titers of anti-Tg antibodies in her sera were in the normal range. Case 3; A woman, who was diagnosed as having Graves' disease at the age of 11, had been treated with MMI or PTU. Presence of anti-T3 and anti-T4 antibodies were found in her sera in a screening test. Serial sera obtained during the 4 year treatment period were tested. Case 4; A woman, who was diagnosed as having Graves' disease at the age of 14, had been treated with MMI. Presence of anti-T3 and anti-T4 antibodies was found in her sera in a screening test. Serial sera obtained during the 2 year treatment period were tested. Titers of anti-Tg were increased when the levels of TSH or titers of TRAb were increased. The results suggested that TSH and TRAb, which are thyroid stimulating substances, increased serum levels of Tg, which resulted in the increase of titers of anti-Tg. Because of the possibility that administration of PSL could modify B lymphocyte functions, periods during which PSL was administered were excluded from the examination of the correlation between Tg concentrations or titers of anti-Tg and titers of anti-thyroid hormone antibodies, as in Cases 2 and 4, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)