Regulative effects of regulatory T cells on dendric cells in peripheral blood and deciduas from unexplained recurrent spontaneous abortion patients

OBJECTIVE: To study the effect of CD(4)(+)CD(25)(+) regulatory T(Tr) cells on dendric cells (DC) in peripheral blood and deciduas from unexplained recurrent spontaneous abortion (URSA) patients. METHODS: Four URSA patients (abortion group) and 4 normal early pregnant women (control group) were enrolled in this study. Tr cells and DC in the peripheral blood and deciduas were isolated using Ficoll density gradient centrifugation and magnetic cell sorting (MACS). DC were cultured alone (DC alone) or in combination with Tr cells (DC + Tr) for 6 days, during which the release of interferon (IFN)-gamma and interleukin (IL)-10 in the medium was subsequently measured by enzyme linked immunoadsorbent assay (ELISA). RESULTS: (1) Peripheral blood: there was no significant difference in IFN-gamma level between DC alone (23.2 +/- 0.7) ng/L and DC + Tr (22.5 +/- 3.0) ng/L in abortion group (P > 0.05). The similar level of IL-10 was observed between DC alone (37 +/- 7) ng/L and DC + Tr (35 +/- 4) ng/L in abortion group (P > 0.05). IL-10 level, but not IFN-gamma, was significantly higher in DC alone (54 +/- 20) ng/L than that in DC + Tr (36 +/- 9) ng/L in control group (P 0.05). Moreover, Similar IL-10 level was found between DC alone (28 +/- 7) ng/L and DC + Tr (25 +/- 5) ng/L in abortion group (P > 0.05). IFN-gamma level in DC alone (30.7 +/- 4.6) ng/L was significantly higher than that in DC + Tr (22.6 +/- 3.8) ng/L in control group (P < 0.01); whereas IL-10 level was much lower in DC alone (27 +/- 6) ng/L than that in DC + Tr (31 +/- 9) ng/L in control group (P < 0.05). CONCLUSION: The decreasing of immunosuppressive function of Tr cell of URSA patients affect its regulation on DC, resulting in imbalance of Th1/Th2 and abnormality of maternal-fetal immuno-tolerence in URSA.