Decidual CD4+CD25+CD127dim/- regulatory T cells in patients with unexplained recurrent spontaneous miscarriage

Objectives: To investigate the frequency and function of CD4(+)CD25(+)CD127(dim/-) regulatory T (Treg) cells in decidua of patients with unexplained recurrent spontaneous miscarriage (URSM). Study design: The decidual lymphocytes from patients who experienced URSM and normal pregnant women (controls) were collected by Ficoll density gradient centrifugation. CD4(+)CD25(+)CD127(dim/-) Treg cells were isolated by magnetic cell sorting. The proportion of Treg cells and IL-10, TGF-beta in Treg cells were determined by flow cytometry. Inhibitory effects of Treg cells on effecter T cells were detected with or without the presentation of anti-IL-10 antibodies and anti-TGF-beta antibodies. Results: The frequency of CD4(+)CD25(+)CD127(dim/-) Treg cells was decreased in URSM decidua compared to controls (2.09% +/- 0.86% vs. 2.97% +/- 1.19%, p = 0.005), and the expression of IL-10 and TGF-beta in Treg cells was lower in the URSM group than in the control group (p = 0.04 and p = 0.01, respectively). Furthermore, the suppressive effect of CD4(+)CD25(+)CD127(dim/-) Treg cells on the proliferation of effector T cells was decreased in URSM decidua (p < 0.05). Suppression was mediated predominantly through IL-10 and TGF-beta in decidua. Conclusions: Decreased frequency and immunosuppressive capacity of CD4(+)CD25(+)CD127(dim/-) Treg cells was found in URSM decidua. Treg cells inhibit proliferation of effector T cells mainly via IL-10 and TGF-beta in URSM decidua. Crown Copyright (C) 2010 Published by Elsevier Ireland Ltd. All rights reserved.