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

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).

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.

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.

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.