The Role of Analysis of NK Cell Subsets in Peripheral Blood and Uterine Lavage Samples in Evaluation of Patients with Recurrent Implantation Failure.

Objective: In this study, we aimed to determine the role of analyses of NK cell subsets in peripheral blood and uterine lavage samples in evaluation of patients with unexplained RIF. Methods: This retrospective single-institution case-control study included two different cohorts between 2017-2019. First cohort included patients examined with peripheral blood samples for evaluation of possible immunologic problems in patients with unexplained recurrent implantation failure; in the study period, a total of 75 consecutive patients with RIF (study group; n: 42) or infertile patients without RIF (control group; n: 33) were included. Second cohort included those patients whose uterine samples were assessed for immunologic problems; RIF (study group ; n: 16) or infertile patients without RIF (control group; n: 25). Results: In the first cohort, the percentage of NK cells (CD3-CD16(+)56(+)) is statistically significantly lower (9.8 vs. 12.6, respectively, p: 0.038) in the study group than those of the controls whereas there was no statistical significance in the absolute number of NK cells (CD3-CD16(+)56(+)). In the second cohort, the only remarkable finding in uterine lavage samples was significantly increased uNKs cells (CD3-CD16(di)(m)56(bright)) percentages in controls (9.95 vs 12.7, respectively, p: 0.026) compared to those of study group. Conclusion: Our data shows that the analysis of NK cell subtypes in peripheral blood does not seem appropriate to investigate the patients with RIF and we suggest that uterine lavage samples instead of peripheral blood samples be implemented and evaluated. (C) 2020 Elsevier Masson SAS. All rights reserved.