Serum thyrotrophic-receptor auto antibodies levels after 131I therapy in Graves’ patients and effect of pretreatment with ATD

Abstract

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Objectives: there is a transitory increase in levels of thyrotrophic receptors antibodies (TRAb) after radioiodine therapy (131I) in hyperthyroid Graves disease,Immunosuppressive effects of anti thyroid drugs (ATD) are still a matter of debate. In this study we evaluated the effect of anti thyroid drug pretreatment on the TRAb boost induced by 131I. Methods: 41 patients were assigned to receive 131I alone (18 patients) or 131I plus pretreatment with ATD (23 patients). Serum TRAb levels measured on the day of 131I dosing (D0), and at 3 and 6 12 months after 131I administration. half a year after follow-up,there is three prognosis: hyperthyroid (Hyper-group); euthyroid(Eu-group); and hypothyroid (Hypo-group). Results: 1. Before 131I treatment, there is no different in TRAb levels between patients treated with ATD and 131I alone group: 39.95±42.88 U/l, 46.08±51.80 U/l, P>0.05. After 131I treatment, in patients treated with ATD, TRAb levels increased significantly from D0 to 3rd month 39.95±42.88 U/l, 204.32±134.19 U/l, P<0.05 reaching their highest levels at 3rd months. After this, we observed a progressive decrease at 6th months (81.30±92.07U/l). In patients treated with 131I alone, TRAb levels increased at 3rd month 117.86±103.36 vs. 46.08±51.80 U/l; P<0.05. And at 6th months compared with D0 values 105.30±97.70 vs. 46.08±51.80 U/l; P<0.05. After this, we observed a progressive decrease at 6th months. The course of TRAb levels after 131I treatment was significantly different between the two groups (P>0.05). 2. The course of TRAb levels after 131I treatment was significantly different in the three different prognosis groups (P<0.05). A higher TRAb level before 131I treatment was associated with hyperthyroidism after half a year of follow-up. Conclusions: (1)Radioiodine therapy (131I) in hyperthyroid Graves’ disease followed by a transitory increase in levels of TRAb; (2)ATD pretreatment don’t attenuates the 131I -induced rise in serum TRAb levels. (3) high TRAb levels before 131I are associated with a relative resistance to therapy; there is no decrease in TRAb levels between the 3rd and the 6th month after 131I are associated with hypothyroid after half a year of follow-up.