Clinical and Experimental Obstetrics & Gynecology (CEOG) is published by IMR Press from Volume 47 Issue 1 (2020). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with S.O.G.
Objective: This retrospective study aims to investigate the effects of immunosuppressive therapy on the expression of regulatory T (Treg) cells, natural killer (NK) cells, and natural killer T (NKT) cells in patients with recurrent embryo implantation failure (RIF). Materials and Methods: In vitro fertilization and embryo transplantation (IVF-ET) at Jinhua Municipal Central Hospital from July 2013 to November 2015 of 30 RIF patients were enrolled into RIF group, and peripheral blood Treg, NK, and NKT were detected before entering the embryo transfer cycle. Meanwhile, 20 normal non-pregnant women were enrolled into control group. Twenty-four patients in RIF group were administered prednisone; Treg, NK, and NKT cell contents were detected twice before and after the embryo transfer cycle, respectively. The remaining six patients with high NK cell contents were treated with gamma globulin via intramuscular injection, and Treg, NK, and NKT cell contents were detected twice before the embryo transfer cycle and after treatment. Results: Treg cell content was significantly lower in RIF group than in control group, while NK cell proportion was significantly higher in RIF group than in control group before treatment. There was no statistical difference in NKT cells. After treatment, expression rate of Treg in RIF group was 7.1 ± 1.8%, which compared with that before treatment (2.8±1.6%) was significantly higher (p < 0.01). In addition, NK cell proportion was significantly lower than pretherapy (20.9 ± 3.6% vs. 38.6 ± 8.1%, p < 0.05) and NKT cell percentage did not present the obvious difference before and after treatment. Conclusion: The occurrence of RIF may be related to the decrease in Treg expression and increase of NK cells. Immunotherapy can upregulate the expression of Treg and decrease NK cell proportion, thereby regulating maternal fetal immune tolerance and reducing the rejection effect of NK cells on fetal foreign bodies, which are conducive to embryo implantation.