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

Abstract

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-β 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-β 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-β 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-β 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-β in URSM decidua.