Activated T cells in Graves' disease before treatment.

The aim of this study was the definition of abnormalities occurring within T-cell subsets of thyrotoxic Graves' patients before treatment. Special emphasis was placed on the enumeration of activated T cells using a number of new monoclonal antibodies. Lymphocytes from 22 Graves' disease patients were examined. The total number, the percentage of 'helper/inducer' and 'suppressor/cytotoxic' positive cells were evaluated using the antibodies T3, T4 and UCHT4, whereas the cells with killer activity were defined by H25. Activated T cells were detected using the antibodies DA6.231, DA6.164, and L243 which bind different epitopes of the beta chains of class II surface antigens and 4F2, which binds a 120,000 molecular weight glycoprotein. The results show no significant change in the total T, helper or suppressor cell phenotype, but an increase in the killer cell percentage was noted. Of those patients tested, 19 of 22 showed an increase in activated T cells, 18 of 22 patients showed a significant increase of T cells bearing class II antigens, 11 of 22 showed an increase of T cells staining with another activated T cell antibody, 4F2. The anti-DR antibodies expressed different binding characteristics, the most striking difference being seen between the antibodies DA6.231 and L243. The results of this study suggest an heterogeneity of the immune response, or differences in activation stage in patients with Graves' disease before therapeutic intervention. An important role for these cells in the pathogenesis of this disorder can be inferred.