Effects of treatment with methimazole on circulating CD4⁺ and CD8⁺ T cells positive for programed cell death protein-1 and on subsets of CD4⁺ T cells in untreated hyperthyroid patients with Graves' disease.

The expression of PD-1 on circulating CD4⁺ and CD8⁺ T cells is increased in hyperthyroid patients with active Graves' disease. MMI significantly decreases levels of circulating PD-1⁺  CD4⁺ T cells, suggesting that PD-1⁺ T lymphocytes may be associated with the pathogenesis of Graves' disease.