Objective: To investigate the effects of immunotherapy on PRA, TGF-β and CD4+CD25+Foxp3+ nTreg cells in women with unexplained recurrent spontaneous abortion. Methods:We detect the level of PRA,TGF-βin serum and the expression of nTreg cells in peripheral blood of pregnant, non pregnant and natural fertility women by enzyme immunoassay and flow cytometry. Results:After immunotherapy,the median level of PRA and TGF-βin non pregnant group was lower than that in pregnant group(27. 5%,107. 7 pg/L vs 68. 75%,189. 9 pg/L,P<0. 01). Compared to pregnant group,the median expression rate of nTreg cells were lower in non pregnant group(5. 05% vs 8. 05%,P<0. 01). Conclusion:The PRA,TGF-βand nTreg cells are critical factors for pregnancy in RSA patients. It is helpful to identify and judge the effect of immunotherapy by detect the level of panel reactive antibodies,TGF-β in serum and the expression rate of nTreg cells in peripheral blood.