The results show that the high recurrence rate of antithyroid drugs may be related to the insufficient treatment time, the fact that thyroid autoantibodies did not turn negative when the drugs were stopped, and the thyroid volume did not shrink after treatment. However, individual differences are large, and there is no clear conclusion yet. Graves hyperthyroidism is a common organ-specific autoimmune disease, and its diagnosis mainly depends on the detection of thyroid autoantibodies, especially thyroid-stimulating receptor (TRAb). The antigens in thyroid gland include thyroglobulin (Tg), thyroid peroxidase (TPO) and sodium iodide symporter (NIS) besides thyroid stimulating receptor (TR). Graves hyperthyroidism patients were not only positive for TRAb, but also some patients were positive for anti-thyroglobulin antibody (TgAb) and anti-thyroid peroxidase antibody (TPOAb). At present, the traditional antithyroid drug treatment scheme is to adjust the dosage according to whether the thyroid function returns to normal or not, and observe the antibody turning negative at the same time, and only pay attention to whether TRAb turns negative or not. It has been found that whether TPOAb turns negative when stopping the drug can predict the recurrence after stopping the drug, suggesting that it is not only necessary to observe whether TRAb turns negative, but also to pay attention to whether other thyroid autoantibodies turn negative during the treatment of hyperthyroidism. The negative conversion of all antibodies may indicate that autoantigens are no longer exposed, and the immune balance is stable.

Methimazole (MMI) is one of the most important antithyroid drugs in the treatment of Graves' disease. It mainly blocks the synthesis of thyroid hormone by inhibiting the activity of peroxidase and reduces the production of thyroid hormone. At the same time, some studies have found that methimazole has immunomodulatory effect. Methimazole is recommended for initial treatment of first-time Graves' hyperthyroidism. 30mg/d is suitable for severe Graves' hyperthyroidism and 15mg/d is suitable for mild and moderate Graves' hyperthyroidism. Research has used blocking alternative methods to treat hyperthyroidism patients, maintaining the moderate or high dose of methimazole without decreasing, such as adding levothyroxine to treat hypothyroidism when hypothyroidism occurs, in order to suppress the immune state of Graves' disease patients. However, the research results have not found that it can reduce the recurrence rate of hyperthyroidism. Analyzing the results of these clinical studies, it is found that the use time of methimazole in some studies of blocking replacement therapy is short, and the total treatment time is only one year, and all antibodies are not required to turn negative at the end of treatment. Some studies only focus on the negative conversion of TRAb antibody, but not on the negative conversion of other antibodies such as TgAb and TPOAb.

Therefore, in this study, the intensive treatment group was treated with the inhibition substitution method of fixed middle dose methimazole plus levothyroxine, and the antibody was reduced after all turned negative, while the conventional treatment group was reduced according to whether the thyroid function was normal, so as to evaluate the effects of intensive treatment and conventional treatment on the cumulative recurrence of Graves' hyperthyroidism after two years of drug withdrawal. At the same time, the changes of immune indexes and inflammatory factors during the regulation process were evaluated. To provide evidence for improving the clinical remission rate of Graves' hyperthyroidism and exploring the etiology of Graves' hyperthyroidism.