Increased level of soluble interleukin-2 receptor in sera of patients with Graves' disease.

Soluble interleukin-2 receptor was studied in 20 patients with Graves' disease before and after methimazole treatment. Soluble interleukin-2 receptor level was significantly increased in newly diagnosed Graves' disease compared to controls (667 +/- 270 vs 205 +/- 45 U/ml) (P less than 0.001). In untreated patients' sera the soluble interleukin-2 receptor levels were higher in patients with active ophthalmopathy than in those without eye symptoms. Soluble interleukin-2 receptor levels were normalized in remission induced by methimazole treatment in the majority of patients except those with infiltrative ophthalmopathy. Furthermore, a correlation was found at the hyperthyroid stage of the disease between soluble interleukin-2 receptor level and titre of anti-TSH-receptor antibodies. However, the association with other parameters including anti-eye muscle, anti-thyroid peroxidase, anti-thyroglobulin antibodies was not significant.