Immune effect of propylthiouracil and methimazole in the treatment of Graves' disease

Objective To observe the changes in TSH receptor antibody (TRAb) and soluble intercellular adhesion molecule-1 ( sICAM-1 ) levels after treatment of propylthiouracil ( PTU ) and methimazole( MMI ) in patients with Graves' disease (GD). Methods One hundred and six cases of clinically diagnosed patients with GD were divided into PTU and MMI groups( each group, n =53 ). The patients in two groups were regularly followed for 36 months. TRAb and sICAM-1 were measured with ELISA method. Results( 1 ) The general data of two groups were not significantly different before treatment( all P＞0. 05 ). ( 2 ) There was no difference in TRAb positive rates between two groups before treatment. The clinical remission rates between PTU and MMI groups showed no difference (83.02％ vs88.68％ ). The cure rate was higher in MMI group than in PTU group( 58.49％ vs 37.74％, P＜ 0. 05 ). (3) There existed significant differences in TRAb levels determined before and 6, 12, 24,30, and 36 months after treatment( all P＜0. 01 ), being gradually decreased with time( F=275.48 ,P＜0.01 ). TRAb levels between two groups were significantly different( F=5.86, P＜0. 05 ). (4) sICAM-1 levels at 36 months after treatment compared with the baseline in both groups were statistically different (P＜0. 01 ), but no difference was found between two groups. ConclusionsBoth PTU and MMI improve the immune status of patients with GD, and the immunosuppressive effect of methimazole is more evident. Key words: Propylthiouracil;  Methimazole;  TSH receptor antibody ;  Soluble intercellular adhesion molecule-1