Lower HLA-G levels in Extravillous Trophoblasts of Human Term Placenta in Gestational Diabetes Mellitus than in normal controls

Abstract

The non-classical HLA (human leucocyte antigen) class I molecule HLA-G is widely known to play a major role in feto-maternal tolerance. We tested the hypothesis that HLA-G expression is altered in placentas of women with gestational diabetes mellitus (GDM) in a specific pattern depending on fetal sex.HLA-G expression was analysed in a total of eighty placentas (40 GDM/ 40 controls) by immunohistochemistry using the semi-quantitative immunoreactive score (IRS). Double-immunofluorescence staining identified the cells expressing HLA-G in the decidua and to evaluate the expression pattern. We found a significant (p<0.001) reduction of HLA-G expression in extravillous cytotrophoblasts in GDM as compared to controls. We could demonstrate that this downregulation is not due to a loss of cell number, but to a loss of expression intensity. We found a special change in cell pattern in extravillous trophoblastic cells: They show an obvious rarefication on HLAG expression on EVT cell surface. No significant differences according to fetal sex were found.These data show that GDM alters HLA-G expression in EVT cells and provide new insights in altered placental function in diabetic placenta.