Problem The aim of this study was to investigate the influence of sexual intercourse on uterine NK cell subsets.
Method of study Mid-secretory endometrial samples obtained from 56 women were submitted for flow cytometric analysis. Basal body temperature was used to determine the day of ovulation. A total of 27 women had sexual intercourse before ovulation (pre-ovulation group) and eight women had only after ovulation (post-ovulation group) without any contraceptive devices. A total of 21 women did not have sexual intercourse during the experimental cycle (abstinence group). Endometrial NK cells were analyzed for the expression of CD16 and CD56 using 3-color flow cytometry.
Results CD16−/CD56bright cells were markedly increased in the pre-ovulation group as compared with that of the post-ovulation group (P < 0.01) and the abstinence group (P < 0.01). CD16+/CD56dim cells were significantly decreased in the pre-ovulation group as compared with that of the post-ovulation group (P < 0.01) and the abstinence group (P < 0.05).
Conclusion It is suggested that seminal plasma participates in the recruitment of CD56bright NK cells into endometrium.