Hyperthyroidism of Graves' disease takes an unpredictable clinical course in the long-term follow-up. Whereas roughly 30-60% of patients relapse after their first antithyroid drug treatment, the likelihood of remission in the remaining group can not be foreseen. We have analysed-retrospectively-patients with Graves' disease that had been on antithyroid drug treatment for one year and were followed up thereafter. Patients were investigated for a variety of clinical parameters like ophthalmopathy status and relapse or remission as well as gene polymorphisms of the HLA and other regions. Of the 259 patients analysed so far, patients with ophthalmopathy did not differ from those without for HLA DQA1 and CTLA4 alleles tested. Also, the subgroup of patients with relapses after antithyroid drug treatment showed no different distribution of those alleles from the group with long-term remission. This study also confirms that the allele HLA DQA1* 0501 confers susceptibility to Graves' disease, furthermore, that the CTLA4-alanine 17 allele is an additional predisposing factor.