Influence of TRAb on TSH in treated euthyroid patients with Graves disease

Objective To investigate the change in levels of TRAb and TSH in patients with Graves disease,and to examine whether TRAb has inhibitive effect on TSH.Methods After Propylthiouracil(PTU) treatment,91 patients with Graves disease became euthyroid for at least 2 months.Among them,44 patients had low TSH level,while the other 47 had normal TSH level.The levels of TRAb between the two groups were compared.Results There were no significant differences in levels of FT3 and FT4 between the groups.The level of TRAb in low TSH level group was significantly higher than that in normal TSH group(P0.001),and TRAb levels were negatively correlated with TSH levels(r=-0.374,P0.001).Conclusion Thyrotropin suppression in treating euthyriod patients with Graves disease may be attributed to TSH receptor antibody activity.