Characterization of fetal monocytes in preeclampsia and fetal growth restriction

Background: There is little available data on fetal monocyte phenotype and function. A prospective cross-sectional pilot study was conducted to describe the cord blood monocyte subset phenotype in preeclampsia (PE) and fetal growth restriction (FGR) as compared to normal pregnancy and maternal circulation. Methods: Maternal and cord blood samples from 27 pregnancies were collected at delivery from normal pregnancy, PE, FGR and PE+ FGR. The distribution of fetal monocyte subtypes was characterized by CD14 and CD16 expression using flow cytometry and compared for each clinical group using a classification of classical, intermediate and non-classical subsets. Results: The intermediate monocytes were the dominant monocyte subset in the cord blood of PE and PE+ FGR with an increase in the combined inflammatory monocyte subsets intermediate and non-classical in PE compared to normal pregnancy. The non-classical monocyte subset proportion was elevated in all pathological groups PE, FGR and PE + FGR. A significant reduction in the non-classical monocyte subset was observed in the cord blood of the normal pregnancy group as compared to the maternal circulation. Conclusion: This study describes for the first time in the fetal circulation, dominant monocyte intermediate subsets and increased inflammatory subsets in PE as well as increased non-classical subsets in PE and FGR compared to normal pregnancy.