Placental hla-g expression among women living or not with HIV-1

Introduction: The immune checkpoint HLA-G molecule is highly expressed in the placenta’s extravillous trophoblast cells and has a pivotal role in immune tolerance during pregnancy. Since HIV-1 can infect trophoblast cells and may modify HLA-G expression to subvert host immune defenses, in this study we evaluated the HLA-G expression in third-trimester placental tissue of women living or not with HIV-1. Methods: Immunohistochemistry assay to evaluate HLA-G staining of 183 fragments of paraffin-embedded placental tissue, of which 90 from HIV-1-positive women(HIV+) and 93 from non-positive women(HIV-), were performed. Results: HLA-G staining was observed in extravillous trophoblast(EVT) cells and endothelial and Hofbauer cells, but not in syncytiotrophoblast for both. According to the magnitude of HLA-G staining, HIV-1-non-positive placenta exhibited increased HLA-G staining [negative(6.70%) and 3+(60.00%)], when compared to infected placenta, [negative(30.10%) and 3+(45.16%)] (P<0.01). Overall, decreases in HLA-G expression were significantly associated with pregnancy HIV-1 infection [P<0.01; odds ratio: 2.47(95% CI: 1.47–4.14)]. Other biomarkers of HIV-1 infection like viral load, CD4+ T-cell count, and antiretroviral therapy used during pregnancy showed no association with HLA-G. Conclusion: Our findings suggest that HIV-1 infection can modulate HLA-G expression in EVT cells, which may contribute to an immunological environment affecting the outcome of infection.