Flow cytometric analysis of NK22 cells function in peripheral blood and endometrium obtained from women with recurrent pregnancy loss

Abstract

Problem: It is considered that NK22 cells might mediate mucosal immune defense in several organ. In response to pathogen, IL-23 stimulates NK22 cells to secrete IL-22. It is only reported that NK22 cells were present in the uterinemucosa. Toexamine theNK22 function,we investigated theproductionand relationof IL-22and theother cytokines using endometrium (EM) and peripheral blood (PB) NK cells of women with recurrent pregnancy loss (RPL). Materials and methods: Cytokines production (IFNgamma, TNF-alpha, IL-4, IL-10, IL-22, TGF-b1) by PB and EMNK cells and the expression of Nkp46were analyzed by triple color flow cytometry inwomenwith RPL (n=43) and controls (n=38). Moreover, we classified into four groups with high or low percentage of IL-22 production (RPL-H, RPL-L, Control-H and Control-L). Results: In EM, the percentage of NK22 cells in women with RPL was significantly higher than that of controls (p<0.05). In PB and EM, the percentage of IFN-gammaproducing NK22 cells in RPL-H was significantly lower than that in Control-L (p<0.05). There were negative correlations between NK22 cells, and IFN-gamma (r=−0.6) or TNF-alpha (r=−0.6) in women with RPL. There was a negative correlation between CD56bright/IL-22+ cells and CD56bright/NKp46+ cells (r=−0.271). Conclusions:NK22 cell might play an important role in women with RPL by regulating cytokine production by NK cells.