Reduction in the suppressor-inducer T cell subset and increase in the helper T cell subset in thyroid tissue from patients with Graves' disease.

The expression of surface markers associated with activation and characterization was compared among T cells in thyroid glands and peripheral blood of 10 patients with Graves' hyperthyroidism receiving chronic antithyroid drug therapy, in peripheral blood of 15 patients with untreated hyperthyroid Graves' disease, and in peripheral blood of 21 normal subjects using two-color flow cytometry. In the chronically treated Graves' disease patients, the percentage of activated T cells (HLA-DR+ T cells) among total T cells was significantly higher in thyroid tissue than in peripheral blood, and the increase in percent activated T cells was also significant among both helper/inducer T cell (CD4+ cell) and suppressor/cytotoxic T cell (CD8+ cell) subsets. The percentage of activated T cells in peripheral blood was not significantly different between chronically treated hyperthyroid Graves' patients and normal subjects, whereas the percentage of activated T cells in the peripheral blood from untreated hyperthyroid Graves' disease patients was significantly higher than that in normal subjects or chronically treated hyperthyroid Graves' patients. The percentages of CD4+ cells and CD8+ cells among total T cells were not different between thyroid tissues and peripheral blood in patients with chronically treated hyperthyroid Graves' disease. When CD4+ were further divided into helper T cells (CD4+2H4- cells) and suppressor-inducer T cells (CD4+2H4+ cells) using two-color flow cytometry, the percentage of helper T cells among CD4+ cells was significantly higher in thyroid tissue than in peripheral blood, resulting in an increased ratio of CD4+2H4- cells to CD4+2H4+ cells. The percentage of CD4+2H4+ cells in peripheral blood, however, was not significantly different among untreated and chronically treated Graves' disease patients and normal subjects. From the findings of abnormalities in intrathyroidal T cell subsets, we suggest that the decrease in the function of suppressor T cells within the thyroids of Graves' disease patients may be due to a decrease in CD4+2H4+ cells within thyroid tissue.