Are CD57+ Natural Killer cells really important in early pregnancy failure?

The aim of this study was to compare the CD57+ Natural Killer (NK) cell counts in normal pregnancies and in cases grouped according to different types of early pregnancy failure. A prospective case control study which was set in Baskent University Faculty of Medicine, Obstetrics and Gynecology Department. A total of 119 women whose pregnancies ended in the first trimester were divided into elective pregnancy termination, incomplete miscarriage, intrauterine demise, ectopic pregnancy and recurrent pregnancy loss groups. CD57+ NK cells were stained and counted in the histologic preparations of the decidua in all of these groups. CD57+ NK cell counts were 2.14 +/- 1.42 in control, 2.24 +/- 1.92 in incomplete miscarriage, 1.82 +/- 1.34 in intrauterine demise, 2.54 +/- 1.80 in ectopic pregnancy and 3.42 +/- 2.15 in recurrent pregnancy failure group. There were no statistically significant differences between the control group and the other four groups with respect to the CD57+ NK cell counts. This study suggests that CD57+ NK cell count is not associated with early pregnancy failure.