Proportional change of CD4+CD25+ regulatory T cells in decidua and peripheral blood in unexplained recurrent spontaneous abortion patients

ObjectiveTo investigate the proportional changes of CD4+CD25+ regulatory T cells in peripheral blood and decidua in unexplained recurrent spontaneous abortion (URSA) and normal pregnant (NP) women.DesignProspective, case–control study.SettingLarge public hospital in a major city in China.Patient(s)Twenty-five URSA patients and 34 normal, early pregnant, control women.Intervention(s)Measurements of CD4+CD25+ regulatory T cells in decidua and peripheral blood.Main Outcome Measure(s)The proportion of CD4+CD25bright regulatory T cells; the percentage of CD25bright cells in the CD4+ T-cell population.Result(s)The proportions of CD4+CD25bright T cells in both decidua and peripheral blood in URSA patients were statistically significantly lower than those in control women. Meanwhile, the percentage of CD25bright cells in the CD4+ T-cell population in decidua was statistically significantly lower in URSA patients than in control women. The percentage of CD25bright cells in the CD4+ T-cell population in decidua was statistically significantly higher than that in peripheral blood in control women, whereas the difference was not significant in patients who have URSA.Conclusion(s)Human CD4+CD25bright T cells play a major role in tolerating conceptus antigens and therefore may contribute to the maintenance of pregnancy. The data suggest that CD4+CD25+ regulatory T cells may be a novel target in URSA therapy.