Summary

Chorioamnionitis (CA) is a severe infection responsible notonly for premature birth but also for many severe neonataldiseases. The aim of the present study was to investigate theexpression of CD40L and P-selectin on platelets and the plasmalevels of their soluble forms in the umbilical cord blood in infantswith documented chorioamnionitis. Umbilical cord bloodsamples were obtained from 10 healthy term newborns,10 noninfectedpreterm infants, 10 preterm infants with prematurerupture of membranes and 9 preterm infants with clinical andhistological CA.The expression of CD40L and P-selectin on plateletswas analyzed by flow cytometry. Soluble P-selectin(sCD62P), soluble CD40L (sCD40L) and interleukine-6 (IL-6)were measured in plasma by ELISA assays. Neonates with CAhad significantly higher percentages of platelets expressingCD40L in basal conditions (5.3 ± 2.9% vs. 1.6 ± 0.7% and in noninfected preterm infants p < 0.05), while the percentages of Pselectinpositive platelets were similar among all groups. Incontrast, the level of sP-selectin was higher in infants with CA(222 ± 128 ng/ml vs. 104 ± 71 ng/ml in non-infected preterm infants,p < 0.05) but no differences were found in the levels ofsCD40L.As expected, the levels of IL-6, a pro-inflammatory cytokinewere significantly higher in samples obtained from pretermneonates whose mothers had also elevated inflammatoryparameters. Our observations suggest that platelets are involvedin the complex inflammatory pathogenesis of CA.Neither P-selectin expression on cord blood platelets nor plasmasP-selectin or sCD40L were suitable platelet markers in CA,whereas CD40L was significantly elevated in histologically provenCA