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

ProblemNK lymphocytes play critical yet poorly defined role in implantation and during development in early pregnancy.Methods of studyRecently, we showed that the proportion of NK that expressed CD69+ after incubation with K562 (CD69stim) cells reflected the NK population excitation potential. In the present study, we investigate the significance of NK activation levels in predicting embryo implantation.ResultsA qualitative analysis of values distribution in two groups showed that 25/33 (75.8%) women who became pregnant had CD69stim levels that were >30 but <60% (conditionally normal zone). In contrast, CD69stim levels in patients who failed to become pregnant were either elevated, as in 10/51 (19.6%), or reduced, as in 20/51 (39.2%) of the patients. Accentuated CD69stim levels were predictive for implantation failure, extremely significant for decreased (OR 6.9, p = 0.0004) and not quite significant for increased CD69stim levels (OR 3.9, p = 0.062). Accordingly, conditionally normal CD69stim levels were favourable for implantation (OR 4.46, p = 0.0032).ConclusionWe confirm that actual peripheral blood natural killer cells activation status have an influence on embryo implantation. We showed that exactly normal NK cell activity predicting successful implantation.