Serial analysis of circulating T gamma/delta lymphocyte subpopulations in Graves' disease

In the present paper the distribution of peripheral blood T gamma/delta lymphocytes in Graves' disease patients is analyzed in order to correlate them with disease activity and with prognosis. Eighteen patients with Graves' disease, 24 patients with Hashimoto's thyroiditis and 32 sex- and age-matched healthy control subjects were studied. Peripheral blood CD3+ alpha/beta and gamma/delta T lymphocytes as well as CD4+ and CD8+ T cells, and CD19 (B) lymphocytes were analyzed by cytofluorometry. At diagnosis, patients who required a radical treatment for thyrotoxicosis control showed a significant decrease of T gamma/delta lymphocytes and an increase of B cells when compared with those who maintained the euthyroid state after methimazole. No correlation was detected between the percentages of these subpopulations and serum free thyroxine. This decreased proportion did not normalize after methimazole or radical treatments. These results suggest that the cytotoxic T gamma/delta compartment of the immune system is altered in patients with Graves' disease.