Triiodothyronine autoantibodies in Graves' disease: their changes after antithyroid therapy and relationship with the thyroglobulin antibodies.
Sera of 63 patients with Graves' disease, and 49 control subjects were assayed for T3 autoantibodies by a sensitive radioimmunoassay after being stripped of the endogenous thyroid hormone. T3 autoantibodies were demonstrated in 27% of patients with Graves' disease. After antithyroid treatment, T3 autoantibodies in 75% of the patients with positive antibody before therapy changed to negative titre during a follow-up period of 1 to 12 months. Also, a significant decrease of T3 autoantibodies was observed at 1 month after therapy in all patients who received antithyroid treatment. A further study of T3 autoantibodies and anti-thyroglobulin antibodies showed that the latter were demonstrated in 100% of patients with positive T3 autoantibodies and that T3 autoantibodies existed in about one third of patients with positive anti-thyroglobulin antibodies. The results suggested that T3 autoantibodies could be a subpopulation of the heterogenous anti-thyroglobulin antibodies. Although the fall of T3 autoantibodies in some patients was correlated to that of anti-thyroglobulin antibodies, the overall correlation between T3 autoantibodies and anti-thyroglobulin antibodies was poor.


CONCLUSIONS
1. T3 autoantibodies may be suppressed by antithyroid drugs. 2. Being a subpopulation of anti-thyroglobulin antibodies, T3 autoantibodies may be caused by an antigenic site within the big thyroglobulin molecule, whereas their titre was not correlated with that of the overall heterogenous anti-thyroglobulin antibodies.
Department of Metabolism, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, ROC.
P W
PW
Wang
M J
MJ
Huang
R T
RT
Liu
C D
CD
Chen
D000293:Adolescent; D000328:Adult; D000368:Aged; D000906:Antibodies / Q000032:analysis*; D013956:Antithyroid Agents / Q000627:therapeutic use*; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D005260:Female; D006111:Graves Disease / Q000097:blood / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013954:Thyroglobulin / Q000032:analysis / Q000276:immunology*; D014284:Triiodothyronine / Q000032:analysis / Q000276:immunology*
D000906:Antibodies; D013956:Antithyroid Agents; D001323:Autoantibodies; D014284:Triiodothyronine; D013954:Thyroglobulin