Selective loss of regulatory T cells in thymomas.

Myasthenia gravis (MG) is the prime autoimmune manifestation of thymomas. We investigated the generation of T cells with a regulatory phenotype (TR) in thymomas with and without associated MG. In patients with MG(+) thymomas, maturation and export of TR cells but not of other T-cell subsets was significantly reduced. We conclude that imbalance between effector and regulatory T cells in thymomas may be involved in modulation of onset and/or severity of MG. Ann Neurol 2004;56:901–904