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.