Peripheral blood natural killer cells activation status determined by CD69 upregulation predicts implantation outcome in IVF.

Problem: NK lymphocytes play critical yet poorly defined role in implantation and during development in early pregnancy.

Methods Of Study: Recently, we showed that the proportion of NK that expressed CD69⁺ after incubation with K562 (CD69(stim)) cells reflected the NK population excitation potential. In the present study, we investigate the significance of NK activation levels in predicting embryo implantation.