HLA Class I protein expression in the human placenta

The authors investigate the expression of classical and non-classical HLA class I proteins in the human placenta to understand their role in maternal tolerance towards the semiallogeneic fetus. They find that while classical HLA proteins are present in non-trophoblastic cells, the syncytiotrophoblast lacks HLA class I expression, with extravillous trophoblasts showing high levels of HLA-G and HLA-C. The study highlights ongoing debates regarding the expression patterns of HLA-G isoforms in various placental cell types, suggesting a need for further research using isoform-specific antibodies.