SHORT COMMUNICATION Serial analysis of the effects of methimazole or radical therapy

The distribution of peripheral blood CD16/56 cytotoxic T and natural killer (NK) cells in Graves’ disease patients is analyzed in order to correlate them with disease activity and with prognosis. Eighteen patients with Graves ’ disease, twenty-four patients with Hashimoto’s thyroiditis and thirty-two sex- and age-matched healthy control subjects were studied. Peripheral blood CD16/56 (cytotoxic T and NK) cells were analyzed by cytofluorometry. A decreased proportion of CD16/56þ and CD16/ 56þCD3þ cells were detected in Graves ’ disease patients when compared with thyroiditis patients and healthy control groups. No correlation was detected with serum free thyroxine. On diagnosis, patients who would require a radical treatment for thyrotoxicosis control showed a significant decrease of cytotoxic CD56þ T (CD3þ) and NK (CD3) cells compared with those who would maintain the euthyroid state after methimazole. These results suggest that the cytotoxic compartment, both T and NK cells, of the immune system is altered in patients with Graves ’ disease, independently of the functional thyroid status. Changes in peripheral blood lymphocytes in Graves ’ disease patients could be useful as predictive markers of an unfavorable outcome. European Journal of Endocrinology 139 314–31