The decrease in non-specific suppressor T lymphocytes in female hyperthyroid Graves' disease is secondary to the hyperthyroidism.

There has recently been considerable interest generated in the significance of changes in the peripheral blood T lymphocyte subsets in patients with autoimmune thyroid disease. Previously, monoclonal antibodies that recognized T cells (Leu 1+ cells), T helper/inducer cells (Leu 3a+ cells), and T suppressor/cytotoxic cells (Leu 2a+ cells), have been used to enumerate these subsets. Using 2 new monoclonal antibodies (anti-Leu-8 and anti-Leu-15), in addition to the above 3 antibodies, and 2-colour flow cytometry, we have enumerated the total T, T helper/inducer, T suppressor/cytotoxic, T helper (Leu 3a+8-), T inducer (Leu 3a+8+), T suppressor (Leu 2a+15+), and T cytotoxic (Leu 2a+15-) cells in 22 patients with hyperthyroid Graves' disease, 38 patients with 131I-treated Graves' disease and 10 patients with Hashimoto's thyroiditis. All patients and controls were female. We found that hyperthyroid patients with Graves' disease had significantly lower T suppressor/cytotoxic cells (p less than 0.05) than did controls, and that this was mainly due to a decrease in T suppressor cells (p less than 0.01). Furthermore, patients with severe hyperthyroidism had a more significant decrease in T suppressor/cytotoxic (p less than 0.001) and T suppressor (p less than 0.001) cells, and an increase in the T helper/inducer:T suppressor/cytotoxic (p less than 0.01) and T helper:T suppressor (p less than 0.01) cell ratios. Patients who were euthyroid more than 1 year after 131I therapy for Graves' disease had normal T cell subsets and ratios, whether or not TSH receptor antibody or other thyroid auto-antibody titres were elevated. Ten females with Hashimoto's thyroiditis also had normal T cell subsets.(ABSTRACT TRUNCATED AT 250 WORDS)