[Effect of hypo- and hyper- accentuated NK cell activity on embryo implantation].

NK lymphocytes play an important role in implantation and during development in early pregnancy. 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 investigated the significance of NK activation levels in predicting the implantation outcome in 84 patients following IVF (in vitro fertilization). Remarkably, the patients with an accentuated increase or a decrease of the levels of NK activity, have unfavourable conditions for implantation (9.1%, 3/13 and 15.1%, 5/25, respectively) compared to the patients with the nominally normal levels (52.2%. 25/46). Therefore, a nominally normal level of the NK activity is an important physiological condition and predictive factor for immune readiness to embryo implantation. This study describes an easy, efficient, sensitive and informative method for measuring NK cell activity that is relevant to clinical trials.