title: Proliferation of T8-positive cytolytic T lymphocytes in response to thyroglobulin in human autoimmune thyroiditis: analysis of cell interactions and culture requirements.
abstract: These experiments were designed to analyze the involvement of T-lymphocyte subpopulations in autoimmune thyroid disorders such as Graves' Disease (GD) and Hashimoto's Disease (HD). In a first set of experiments, lymphocytes isolated from thyroid infiltrates or from peripheral blood of GD and HD patients were analyzed for the expression of various surface antigens. While HLA-DR + T cells were numerous among thyroid infiltrating T lymphocytes in both groups of patients, the proportions of T8 + cells (as defined by their reactivity with the B 9.4 monoclonal antibody specific for T8 surface molecule) were strikingly different in HD and GD. In the latter group of patients only 19% of infiltrating T cells were T8 +, whereas these cells represented approximately 50% in four HD patients. Given the previous demonstration that all T cells expressing T8 antigen are cytolytic T lymphocytes (CTL) or their precursors (CTL-P) in conjunction with the fact that lymphocytes from HD or GD patients are known to proliferate in vitro in response to human tg (Htg), we further analyzed the T-cell subset(s) responsible for in vitro proliferation to Htg. In these experiments, peripheral blood T lymphocytes purified from patients with GD or HD were cultured with 1 microgram/ml Htg and irradiated autologous T-depleted mononuclear cells as the source of antigen presenting cells (APC). The proportions of T8 + cells declined considerably during culture in GD patients, but at Days 6 to 9, T8 + cells represented as much as 51% of cultured T lymphocytes from patients with HD. Moreover, the majority of T8 + cells were medium-large size lymphoblasts. Removal of Htg at Day 6 resulted in both abrogation of proliferative responsiveness and in decreases of T8 + percentages. Further analysis of the cell interactions leading to T8 + cell proliferation in response to Htg showed that helper/inducer T cells, as defined by 5/9 antigen expression, were strictly required. Collectively, these features are reminiscent of the T-cell involvement in experimental autoimmune thyroiditis of mice and stress for the first time the potential role of CTL in tissue damage occurring in Hashimoto's thyroiditis.
mesh_terms: D000328:Adult; D000954:Antigens, Surface; D001323:Autoantibodies / Q000032:analysis; D001327:Autoimmune Diseases / Q000097:blood*; D002450:Cell Communication; D005260:Female; D006111:Graves Disease / Q000097:blood / Q000276:immunology; D006386:Hemagglutination Tests; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D008861:Microsomes / Q000276:immunology; D008875:Middle Aged; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D013954:Thyroglobulin / Q000276:immunology / Q000494:pharmacology*; D013966:Thyroiditis / Q000097:blood*; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000276:immunology
chemical_list: D000954:Antigens, Surface; D001323:Autoantibodies; D013954:Thyroglobulin