INTERLEUKIN-6 EXPRESSION IN CORD-BLOOD OF PATIENTS WITH CLINICAL CHORIOAMNIONITIS

The objective of this study was to define whether IL-6 is an early mar ker of infection in the newborn. To correlate the occurrence of clinic al chorioamnionitis with the levels of IL-6 expression in neonates, IL -6 was measured in cord plasma by ELISA and in mononuclear cells by re verse transcriptase-PCR before and after mitogenic stimulation. Eight neonates were included in each of the following four groups: elective cesarean section, uncomplicated normal spontaneous vaginal delivery, d elivery after prolonged rupture of amniotic membranes with no evidence of chorioamnionitis, and delivery with evidence of chorioamnionitis. All 32 neonates were clinically well after delivery, and all 16 babies with prolonged rupture of membranes or clinical chorioamnionitis had negative blood cultures. Elevated IL-6 levels were found only in neona tes born to mothers with chorioamnionitis (119.7 +/- 33.5 pg/mL versus 2.71 +/- 0.59 pg/mL, p < 0.005). Mononuclear cells from five of these neonates expressed no IL-6 mRNA in vivo despite elevated levels of IL -6 in their cord plasma. Cord blood mononuclear cells from healthy ter m babies were capable of synthesizing IL-6 in vitro in response to sti mulation with bacterial lipopolysaccharide. These results suggest that IL-6 levels in cord plasma increased with clinical chorioamnionitis, despite the lack of evidence of infection in the neonates. Therefore, we conclude that, although a high level of IL-6 may be a good marker o f chorioamnionitis, it may not be a specific marker of infection in th e newborn.