Circulating activated T cell subsets in autoimmune thyroid diseases: Differences between untreated and treated patients

Abstract

Abstract. To investigate the relationships between lymphocyte subsets and thyroid function, peripheral blood lymphocytes were analysed with cell surface antigens of activated (HLA-DR+) T, helper T (CD4+2H4−, CD4+4B4+) and suppressor-inducer T (CD4+2H4+, CD4+4B4−) cells subsets in 56 patients with Graves' disease, 16 patients with Hashimoto's thyroiditis, 7 patients with typical subacute thyroiditis and 2 patients with the thyrotoxic phase of autoimmune thyroiditis. Both patients with Graves' disease and Hashimoto's thyroiditis had increased percentages of HLA-DR+T (Ia+CD3+) cells as well as HLA-DR+ helper-inducer T (Ia+CD4+) cells, which seemed to be independent of treatments. The percentage of HLA-DR+ suppressor-cytotoxic T (Ia+CD8+) cells was increased in euthyroid or hypothyroid patients with Graves' disease following treatment, but was normal in hyperthyroid patients. The percentages of Ia+CD4+ cells and Ia+CD8+ were also increased in patients with thyrotoxic phases of subacute thyroiditis and autoimmune thyroiditis, whereas these abnormal values normalized in the remission phase. These findings suggest that an increase in Ia+CD4+ cells characteristically occurs during immune system activation in patients with hyperthyroid Graves' disease, Hashimoto's thyroiditis and the thyrotoxic phase of subacute thyroiditis, whereas the activated CD8+ cells in Graves' disease are induced by antithyroidal therapy.