RESUMO
Proper evaluation of immunological factors connected with pregnancy establishment increased the possibility for exact treatment in high risk gestation cases. Hormonal changes during an ovarian cycle may affect immune response, which is crucial for the embryonic implantation. Peripheral Natural killer (pNK) cells are key components of immune systems and their activities could be regulated by sex hormones. In the present study we investigated the effects of estrogen fluctuation on the number of NK cells in vivo during the early follicular and middle luteal phase of menstrual cycle. In 63 healthy women with at least one full term pregnancy and regular menstrual cycle with duration between 24 and 32 days, blood samples have been collected twice for investigation of CD3/CD16/CD56 positive lymphocytes. The mean pNK count in follicular phase was 11.6% with 4.7% variation. The median was 10.6%. The mean pNK count in luteal phase was 12.1% with 5.1% variation, respectively median for cell number 11.8%. The two-tailed t-test comparison did not find any statistical difference despite the slight elevation of pNK cells count in luteal phase. The insignificant variation in pNK cells count objected the suggestion to evaluate immunological status in women with adverse pregnancy outcome in specific phase of menstrual cycle.