Serum HLA-G levels in Pregnant Women with Preeclampsia in Third Trimester

Background and purpose: Preeclampsia is a pregnancy complication with multiorgan involvement caused by the loss of mother's immune tolerance to the placenta and fetus antigen or the wrong adjustment. HLA-G is an immune-modulatory molecule and this study aimed at investigating the levels of HLA-G and its association with incidence and severity of preeclampsia in pregnant women in third trimester. Materials and methods: A case-control study was performed in pregnant women attending Sari Imam Khomeini Hospital and Baqban Clinic, 2015-2016. A total of 71 subjects (in third trimester) was selected meeting the study inclusion criteria. They were divided into two groups; a group with preeclampsia (n=34) and a group of pregnant women without preeclampsia (n= 37, controls). Pregnancy routine lab tests were done and demographic information, blood pressure levels, and incidence of preeclampsia were recorded in both groups. Then, blood sample (5 ml) was collected from all cases and HLA-G levels were measured in serum samples. Results: The mean serum levels of HLA-G were significantly lower in women with preeclampsia (0.58±0.18 ng/L) compared to that of other group (0.78±0.45 ng/L) (P=0.02). Also, the mean serum levels of HLA-G in those with mild preeclampsia was significantly higher than that of cases with severe preeclampsia (P=0.04). Conclusion: Decrease in production of HLA-G molecule is believed to be one of the decisive factors in development and progression of preeclampsia which could be due to abnormalities in gene expression. Therefore, HLA-G molecule and its mechanism should be further studied to prevent this condition.