Pre-B-cell colony-enhancing factor, a novel cytokine of human fetal membranes

OBJECTIVE: Our purpose was to determine whether pre-B-cell colony-enhancing factor (PBEF) is expressed in the human fetal membranes during normal gestation and parturition in the absence of infection and to show its effects on the expression of interleukin (IL)-6 and IL-8. STUDY DESIGN: PBEF was immunolocalized in the fetal membranes from early pregnancy, at preterm, and at term. Its expression was quantitated by Northern analysis in separated uninfected amnion, chorion, decidua, and placenta of patients at term before labor and in full-thickness membranes before and after spontaneous labor at preterm and at term. Amnion-like epithelial (WISH) cells and fetal membrane explants were treated with recombinant PBEF (rhPBEF), and the expression of IL-6 and IL-8 was quantitated. RESULTS: PBEF was immunolocalized throughout gestation in the amniotic epithelium and mesenchymal cells as well as the chorionic cytotrophoblast and parietal decidua. Northern analysis showed significantly more (P<.01) PBEF expressed in the amnion than in either chorion or placenta. Its expression increased after labor at both preterm and term and correlated with that of IL-8 (r=0.87). rhPBEF treatment f WISH cells significantly increased IL-6 (P<.05) and IL-8 (P<.01) gene expression after 4 hours and of IL-8 protein after 24 hours (P<.01); similar 4-hour treatment of fetal membrane explants significantly increased IL-6 (P<.01) and IL-8 (P<.05) gene expression. CONCLUSION: PBEF is a novel cytokine constitutively expressed by the fetal membranes during pregnancy. It increased the expression of IL-6 and IL-8 and may be important in both normal spontaneous labor and infection-induced preterm labor.