T cell receptor phenotypes in autoimmune thyroid disease.

We have examined T cell receptor expression by peripheral blood and thyroidal lymphocytes in Graves' disease and Hashimoto's thyroiditis, using monoclonal antibodies directed against three beta chain variable region families and against the gamma chain. There was no abnormal distribution of positive staining with the beta chain reagents (compared to normal peripheral blood) in either the thyroid or the blood. However, thyroidal lymphocytes contained an excess of gamma-chain-bearing T cells, compared to peripheral blood, in five of the seven patients in whom simultaneous samples were available. The gamma-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 gamma delta type of T cell receptor in thyroiditis.