The trial objective was to determine the peripheral blood NK cells cytotoxic activity effect on trophoblast cells at recurrent pregnancy loss (RPL). The investigation involved non-pregnant women with PRL in proliferating and secretory menstrual cycle phases (PMCPh and SMCPh, respectively); women of 6-7 weeks pregnancy with RPL in past medical history; healthy fertile non-pregnant women in PMCPh and SMCPh, women of 6-7 weeks physiological pregnancy, nulliparity healthy women with regular menstrual function in PMCPh and SMCPh. NK cells cytotoxic activity was determined using peripheral blood mononuclear cells. The target cells were JEG-3 line trophoblasts. It has been established that NK cells cytotoxic activity effect on trophoblasts is lower in SMCPh than in PMCPh in non-pregnant fertile women. The NK cells cytotoxic activity was higher in SMCPh than in PMCPh in non-pregnant women with PRL and also higher than the same value in SMCPh in non-pregnant fertile women. The increased NK cells cytotoxic activity values in SMCPh in women with RPL may be the reason for miscarriage.

BACKGROUND: Currently, more than a hundred immunological biomarkers are known that are important for fertilization, implantation and placentation. AIM: The aim of this study was to assess the immunological profile for the main allo- and autoantibodies in women with reproductive loss and infertility in the North-West region of the Russian Federation. MATERIALS AND METHODS: This prospective cohort study was conducted at the stage of pregnancy planning in 325 women with reproductive disorders (spontaneous miscarriages, missed abortions, infertility, IVF failures) on the premises of the D.O. Ott Research Institute of Obstetrics, Gynecology, and Reproductive Medicine (St. Petersburg, Russia) from 2015 to 2022. The study assessed the immune interface of women with a history of reproductive disorders and matching loci of the HLA class II system (DQA1, DQB1, DRB1) among 100 married couples. RESULTS: In couples with reproductive disorders, coincidences of HLA class II allele (DQA1, DQB1, DRB1) loci were diagnosed in 14% (at 2 loci), 31% (at 3 loci), 14% (at 4 loci), 3% (at 5 loci) and 10% (at 6 loci) of couples. In 34.4% of women, we found an elevated number of spontaneously activated NK cells (CD107a). As many as 31.15% of women had a high level of antibodies to human chorionic gonadotropin. We found that 22.34% of women were carriers of at least one criteria antiphospholipid antibody, and 3.16% of women of two antiphospholipid antibodies. The diagnosis of antiphospholipid syndrome was not established in any patient. Non-criteria antiphospholipid antibodies were found in 6.15% of women. In 12.2% of women, we diagnosed a high level of antibodies to thyroperoxidase, while the average antibody value was 30.76 IU/ml. Only one patient had a high level of antisperm antibodies in the blood serum. CONCLUSIONS: In 59% of patients with a history of reproductive disorders, we identified some features of the immunological profile, which can lead to this pathology. Thus, 32% of women had a deviation in one immunological parameter, while 20% of patients had it in two parameters, and 7% in three or more parameters.