T cell receptor phenotypes in autoimmune thyroid disease

Abstract

We have examined T cell receptor expression by peripheral blood and thyroidal lymphocytes in Graves’ disease and Hashimoto’s thyroidits, using monoclonal antibodies directed against three β chain variable region families and against the γ chain. There was no abnormal distribution of positive staining with the β chain reagents (compared to normal peripheral blood) in either the thyroid or the blood. However, thyroidal lymphocytes contained an excess of γ-chain-bear-ing T cells, compared to peripheral blood, in five of the seven patients in whom simultaneous samples were available. The γ-chain-positive T cells were not altered in the blood lymphocyte population of untreated Graves’ patients. These results suggest that the T cell response in autoimmune thyroid disease is polyclonal and that there may be a role (such as cytotoxicity) for T cells expressing the γδ type of T cell receptor in thyroiditis.