[Immune activity and serum interleukin-2-receptor concentration in autoimmune thyroid diseases]

Serum interleukin-2 receptor (IL-2R) concentrations were compared in 55 patients with thyrotoxicosis (14 men, 41 women, mean age 43.5 +/- 17 years), 18 patients with Hashimoto's thyroiditis (5 men, 13 women, mean age 47 +/- 15 years) and 28 healthy subjects (12 men, 16 women, mean age 30 +/- 10 years). The patients with thyrotoxicosis were divided into three groups depending on the activity or stage of the disease: 17 patients with florid untreated hyperthyroidism, 23 euthyroid patients receiving treatment with antithyroid drugs and 15 patients with thyrotoxicosis in remission after completing one year's antithyroid treatment. The patients with untreated thyrotoxicosis had significantly higher IL-2R values than the euthyroid patients receiving treatment or those in remission (207 +/- 112 vs 139 +/- 66 and 91 +/- 26 U/ml, P < 0.05 and P < 0.01). The IL-2R values of patients with thyrotoxicosis in remission were, however, significantly lower than those of the 28 healthy subjects (126 +/- 34 U/l; P < 0.01) or the euthyroid patients receiving treatment (P < 0.05). The 18 patients with Hashimoto's thyroiditis had significantly lower serum IL-2R values (70 +/- 39 U/ml) than the healthy controls. These data show that the serum IL-2R level depends on the state of thyroid metabolism and on the activity phase of the thyrotoxicosis. The low serum levels of IL-2R in patients with Hashimoto's thyroiditis could signify a genetically determined decrease in IL-2R production or might be linked with the destruction of thyroid tissue by the chronic autoimmune process.