Investigation of Peripheral Natural Killer Cell Activity in Recurrent Miscarriages of Unknown Cause

Aim: Recent studies on alloimmune factors have shown that Natural Killer (NK) cells may have a role in the implantation and maintenance of pregnancy. It is unclear precisely what kind of relationship exists between uterine and peripheral blood NK cells. Our study aims to investigate the relationship between pNK cells and recurrent pregnancy loss. Material and Methods: Among the patients who applied to the outpatient clinic at University Hospital, retrospectively, women with two or more pregnancy losses constituted the RM group, and women with two or more live births and no miscarriage formed the control group. Two or more miscarriages before 20 weeks of gestation were accepted as the criterion to consider a case of recurrent pregnancy loss. Results: To investigate the etiology of miscarriage in RM patients, parameters associated with the cytotoxicity of pNK cells in women with RM and control fertile women were evaluated. Although the median pNK activity level was relatively higher in the recurrent low group compared to the control group, there was no significant difference between the groups in our study (p=0.448). Discussion: The present study found no significant difference in the percentages of CD56+dim and CD56+bright pNK cells between the patient group with unexplained RM and the healthy fertile control group. There was also no significant difference in CD8 and CD158a expressions in pNK cells between the patient group with unexplained RM and the healthy fertile control group.