HLA-G protein concentrations in maternal serum and placental tissue are decreased in preeclampsia

Objective The aim of this study were to determine whether soluble human leukocyte antigen–G protein levels in serum and/or human leukocyte antigen protein in placental tissues differ between women with preeclampsia versus uncomplicated pregnancies. Study design human leukocyte antigen–G levels were determined with the use of a specific enzyme-linked immunosorbent assay in 20 subjects with preeclampsia and 14 normal control subjects. Results Both serum and placental human leukocyte antigen–G levels were decreased significantly in the preeclampsia group (median, 0.026 μg/mL in serum; median, 0.026 μg/mg protein in placenta), in comparison with normal pregnant women (median, 0.093 μg/mL in serum; median, 0.088 μg/mg protein in placenta; P = .0112 and P = .0406, respectively). There was a significant correlation between serum and placental human leukocyte antigen–G levels (r = 0.603; P = 0.0002). Conclusion The reduced expression of placental human leukocyte antigen–G and reduced release of this protein into the maternal circulation in preeclampsia may alter the maternal-fetal immune relationship and thus be involved in the cause of this disorder.