بررسی تعداد سلول‌های کشنده طبیعی و بیان HLA-G1 در خون محیطی خانم‌های باردار تهدید به سقط

Background: Pregnancy is a phenomenon that antigens of semi allogenic fetus are in direct contact with mother's immune system. Immune dysregulation can cause fetus rejection by mother's immune system responses. Human leukocyte antigen-G1, as an immunotolerant molecule has a major role to induce tolerance during pregnancy by suppression of natural killer cells through inhibitor receptors on these cells. Natural killer cells have an important role in immune surveillance and these cells can be reaction with HLA-G molecules on the trophoblast cells surface. This function prevents natural killer cell invasion against fetus trophoblast cells. The purpose of this study was determination of natural killer cells percent and human leukocyte antigen-G1 expression in peripheral blood of threatened-abortion pregnant women in comparison with control group. Methods: This case-control study was conducted from, February 2014 to October, 2014 in Baghban Clinic in Sari City, Mazandaran province. We investigated 21 threatened-abortion women with light bleeding or spotting less than twenty weeks of pregnancy in comparison with 21 normal pregnant women as control group. Peripheral blood mononuclear cell was isolated by ficoll histopaque (1.077) and natural killer cells percent were evaluated by flow cytometry. Furthermore, we assessed the human leukocyte antigen-G1 isoforms expression by real-time polymerase chain reaction (PCR) in case and control groups. Results: The results of this study was shown that natural killer cells percent in threatened-abortion pregnant women was significantly higher than normal pregnant women (P=0.03). In addition, human leukocyte antigen-G1 isoform had a lower expression in threatened-abortion pregnant women in comparison with control group (P=0.004). Conclusion: Decreasing of human leukocyte antigen-G1 expression with increasing of natural killer cells level in threatened-abortion pregnant women is an indicator of mother's immune system dysregulation in comparison with control group. Therefore, it is concluded that in the threatened-abortion pregnant women, human leukocyte antigen-G1 expression level with natural killer cells percent as diagnostic marker must be determine.