We investigated whether chorioamnionitis affects immunohistochemical demonstration of RECK protein and interleukin-6 (IL-6) expression in fetal placental membranes following late preterm delivery with intact membranes. Fetal membranes of 28 women with single pregnancy, preterm delivery and histologically documented chorioamnionitis at gestational age 34-366/7 weeks constituted the chorioamnionitis study group. The control group consisted of 28 fetal membranes from women with preterm deliveries at the same gestational age without histological chorioamnionitis. Immunohistochemistry was performed using monoclonal antibodies against RECK protein and IL-6. We found a statistically significant difference in RECK expression between the chorioamnionitis and control groups; however, we found no difference in IL-6 expression between the groups. We demonstrated that RECK expression is down-regulated in fetal membranes from pregnancies with spontaneous late preterm birth and intact membranes, which suggests its role in preterm parturition. Equal expression of IL-6 in fetal membranes of pregnancies with and without histological chorioamnionitis is an intriguing and unexpected observation that requires further investigation.
Keywords: Chorioamnionitis; IL-6; RECK protein; fetal membranes; human; pregnancy; preterm delivery.