Chorioamnionitis decreased incidence of respiratory distress syndrome by elevating fetal interleukin-6 serum concentration

Respiratory distress syndrome (RDS) of newborns is one of the most importan t factors determining neonatal morbidity and mortality, The interleukin-6 ( IL-6) titre in cord sera of RDS-free neonates born to mothers with histolog ical chorioamnionitis was significantly higher than that in RDS-complicated neonates without chorioamnionitis, Maternal administration of glucocortico id suppressed the IL-6 concentrations in the cord sera of fetuses with chor ioamnionitis. The fetuses without chorioamnionitis who suffered from RDS ev en after maternal glucocorticoid administration showed a similar IL-6 titre to that of RDS-affected neonates without chorioamnionitis, Examination of the mechanism by which IL-6 decreased the incidence of fetal RDS revealed t hat H441-4, a human pulmonary adenocarcinoma cell line, stimulated with rec ombinant (r)-IL-6 started the synthesis of mRNA and protein of pulmonary su rfactant protein (SP)-A. The present study shows that IL-6 elevation in fet uses with chorioamnionitis promotes fetal lung maturation by inducing SP-A synthesis, thereby decreasing the incidence of RDS in the preterm neonates.