Expression of HLA-G1 at the placental interface of HIV-1 infected pregnant women and vertical transmission of HIV

ObjectivesThe ability of Human Leucocyte Antigen-G (HLA-G) to inhibit the cytolytic effect to immunocompetent cell types, suggests that HLA-G has an immunomodulatory role. In view of this concept the objective of the study was to assess whether the Major Histocompatibility Complex -coded molecule HLA-G mRNA is a risk factor at the placental barrier in HIV-1 positive pregnant women.DesignPlacental HLA-G1 levels in HIV-1 infected mothers and viral loads in both mothers and their babies were performed on fifty-five participants.MethodsSynthesis of complementary deoxyribose nucleic acid (cDNA) was performed using ribose nucleic acid (RNA) extracted from placental tissue samples. Amplification of cDNA using specifically designed primers complementary to the full length HLA-G1 isoform was quantified using real time-polymerase chain reaction (RT-PCR). Viral load assays (Amplicor Version 1.5, Roche Diagnostics) were performed on all plasma samples.ResultsHLA-G1 primers detected the full length isoform HLA-G1 PCR product at 86.5 °C. Logistic regression calculations indicated that the risk of babies becoming infected increased by 1.3 with every 1 unit increase in HLA-G1 expression. Female babies were 3.7 times more likely to become infected than male. There was a positive correlation between mothers’ log viral load and transmission of infection to the baby (p = 0.047; 95%CI 1.029–11.499).ConclusionMaternal viral load was a strong predictor of viral transmission. Placental HLA-G1 expression was up-regulated 3.95 times more in placentas of HIV-1 infected mothers with infected babies when compared to uninfected babies.