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 mu g/mL in serum; median, 0.026 mu g/mg protein in placenta), in comparison with normal pregnant women (median, 0.093 mu g/mL in serum; median, 0.088 mu g/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. (C) 2004 Elsevier Inc. All rights reserved.