Immunological characterization of mononuclear cells in thyroid gland and blood in Graves' disease, multinodular goiter and papillary carcinoma.

Abstract

Mononuclear cell infiltrates in thyroid gland tissue sections from patients with drug-treated Graves' disease (n = 5), non-toxic nodular goiter (n = 12) and papillary carcinoma (n = 5) were characterized by immunological membrane receptors. T lymphocytes were identified using 2-aminoethylisothiouronium bromide hydrobromide (AET)-treated sheep erythrocytes (E) (E-AET). E sensitized with rabbit IgM antibodies (A) and human complement (C) (EAC) were used to detect receptors for C3b (B lymphocytes and monocytes) or C3d (B lymphocytes). E sensitized with rabbit IgG antibodies were used to detect receptors for the Fc portion of IgG (FcR; lymphocytes and monocytes). The results indicate that T and B lymphocytes infiltrate the thyroid gland in Graves' disease as well as in nodular goiter. T lymphocytes seemed to predominate in both disorders. In thyroid papillary carcinoma the number of B and T lymphocytes was negligible. However, EA absorbed strongly to sections from 3 of the 5 tumors studied, indicating the presence of FcR on tumor cells or infiltrating host cells. The percentage of active and total T lymphocytes in peripheral blood from the patients with drug-treated Graves' disease was markedly reduced (9 +/- 5 and 28 +/- 11%, controls 22 +/- 9 and 68 +/- 11%; p less than 0.01 and less than 0.001). In patients with nodular goiter the percentage of total T lymphocytes was slightly, but significantly decreased (p less than 0.05). We suggest that the marked decrease in blood T lymphocytes observed in Graves' disease might be caused by the drug therapy. In nodular goiter the predominance of T lymphocyte infiltration together with a slight decrease in blood T lymphocytes suggest that autoimmune mechanisms are involved in the pathogenesis.