Patients With Autoimmune Thyroiditis Show Diminished Levels and Defective Suppressive Function of Tr1 Regulatory Lymphocytes.

Abstract

T regulatory type 1 (Tr1) cells are a subpopulation of T lymphocytes (CD4+CD49+LAG-3+IL-10+) that exert a considerable immunosuppressive effect. However, their possible role in autoimmune thyroid disease (AITD) has not been explored so far. To analyze the levels and function of Tr1 cells in peripheral blood and thyroid tissue of patients with AITD. Cases and controls, observational study. Department of Endocrinology, Hospital Universitario de la Princesa, Madrid, Spain. Thirty-eight patients with AITD (23 with Graves disease and 15 with Hashimoto thyroiditis) and 26 controls. Multiparametric flow cytometry and immunofluorescence techniques were used to analyze the levels in peripheral blood (n = 38) and thyroid mononuclear cells (n = 5). An in vitro assay of suppression of cellular activation and cytokine release was performed to study the function of Tr1 cells. Levels and function of Tr1 cells in patients with AITD and controls. Levels of Tr1 cells were significantly diminished in peripheral blood from patients with AITD. Functional studies showed that Tr1 cells from patients with AITD exhibit a diminished suppressive function compared with healthy controls. Tr1 levels were associated with disease severity, including longer duration of the disease and ophthalmopathy activity, and with autoantibody titers. The low levels of Tr1 cells and their diminished function may have a relevant role in the defective immune-regulatory function characteristic of patients with AITD.