Infiltrating gamma/delta T-cell receptor-positive lymphocytes in Hashimoto's thyroiditis, Graves' disease and papillary thyroid cancer.

In the present study we have evaluated the expression of different molecular forms of the antigen receptor (TcR) on lymphocytes derived from thyroid tissue of patients with Graves' disease, Hashimoto thyroiditis and papillary cancer both in situ by APAAP technique and on isolated lymphocytes by indirect immunofluorescence. A panel of monoclonal antibodies (mAbs) recognizing alpha/beta and gamma/delta TcR-positive subsets was used. The results showed that the large majority of T-cells in thyroid infiltrates were alpha/beta TcR+, gamma/delta TcR+ ones being very rare or nearly absent, whatever the disease (autoimmune or neoplastic). No difference between gamma/delta TcR+ T-cell subsets (V delta 1+ or V delta 2+) was observed. Thus, neither in autoimmune thyroid diseases nor in papillary cancer gamma/delta TcR+ cells are likely to be a major effector-T cell population.