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

Objective: To 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. Design: Prospective, case-control study. Setting: Large 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(+)CD25(bright) regulatory T cells; the percentage of CD25(bright) cells in the CD4(+) T-cell population. Result(s): The proportions of CD4(+)CD25(bright) T cells in both decidua and peripheral blood in URSA patients were statistically significantly lower than those in control women. Meanwhile, the percentage of CD25(bright) cells in the CD4(+) T-cell population in decidua was statistically significantly lower in URSA patients than in control women. The percentage of CD25(bright) 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(+)CD25(bright) 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.