The effect of mifepristone on the peripheral blood natural killer cell's cytotoxicity and expression of CD94/NKG2A and NKG2D during the implantation phase

Objective: To investigate the effect of mifepristone on peripheral blood natural killer cell's (pbNK) cytotoxicity and the expression of the inhibitory receptor CD94/NKG2A and the activated receptor NKG2D on pbNK cells. Design: In vitro study. Setting: University hospital and research laboratory. Patient(s): Twenty healthy nonpregnant women. Intervention(s): Detected the cytolytic activity of pbNK to K562 target cells; measured the expression of CD94/NKG2A and NKG2D on pbNK. Main Outcome Measure(s): Cytotoxicity of pbNK was detected by Methyl thiazolyl tetrazolium. The expression of CD94/NKG2A and NKG2D receptor on pbNK cells were detected by flow cytometry. Result(s): The NK cell cytotoxicity and the expression of inhibitory receptor CD94/NKG2A during the proliferative phase (81.71 perpendicular to 11.5, 86.6 perpendicular to 9.0) was significantly higher than the secretory phase (60.16 perpendicular to 19.2, 60.15 perpendicular to 31.0). The NK cells cytotoxicity, after being treated with mifepristone and the expression of inhibitory receptor CD94/NKG2A on pbNK cells treated with 200 nmol/L mifepristone, were significantly increased. Mifepristone had no effect on the expression of activating receptor NKG2D. Conclusion(s): These data suggest that Mifepristone maybe exert its anti-implantation function by increasing NK cytotoxicity. The increasing NK cytotoxicity of mifepristone is not related to CD94/NKG2A and NKG2D. In the secretory phase down-regulated CD94/NKG2A, NKG2D, and NK cytotoxicity may benefit with embryo implantation. (Fertil Steril (R) 2010; 93: 2615-20. (C) 2010 by American Society for Reproductive Medicine.)