CD69 and preeclampsia: Preceding studies demonstrated diverse changes in proportions of NK cell subsets in preeclampsia, such as the reduction of vascular endothelial growth factor-expressing NK cells53 and significantly decreased percentage of CD56+/NKp46+ cells and CD56bright/NKp46+ cells in peripheral blood of PE54, while the expansion of CD69+/CD56Dim/CD16+ cytotoxic NK cells was observed at delivery55, which indicate that the changes of NK cells varied from different cell subtypes and gestational ages.