Association between funisitis and elevated interleukin-6 in cord blood

Abstract

Objective: To determine whether elevated plasma interleukin-6 (IL-6) in umbilical venous cord blood at delivery is associated with funisitis and whether IL-6 can be used to screen for funisitis in preterm neonates. Methods: At the time of delivery, umbilical venous cord blood samples were collected from 92 infants for whom placental pathology results were also available. Interleukin-6 concentrations in the umbilical venous cord blood plasma were measured by immunoassay. Histologic examinations of the placenta and umbilical cord were done to determine the presence or absence of funisitis and chorioamnionitis. For a power of 90% with an α of .05, 12 subjects were required in each group. Results: We found a significant association between the presence of histologic funisitis and elevated umbilical venous cord blood plasma IL-6 concentrations (defined as 10 pg/mL or greater). Of 15 infants whose umbilical cords showed funisitis, 93% (14 of 15) had elevated umbilical venous cord blood plasma IL-6 concentrations. Of 77 infants without funisitis, 32% (25 of 77) had elevated IL-6 concentrations in their cords ( P < .001, two-sided Fisher exact test). The negative predictive value of IL-6 as a screening test for funisitis was 98%. Conclusion: In preterm neonates, screening for funisitis by using the immunoassay for IL-6 appears to be valid. In the near future, elevated umbilical venous cord blood IL-6 concentrations at delivery could be clinically useful to identify children who might benefit from early treatment for systemic fetal inflammatory syndrome.