Summary
Chorioamnionitis (CA) is a severe infection responsible not only for premature birth
but also for many severe neonatal diseases. The aim of the present study was to investigate
the expression of CD40L and P-selectin on platelets and the plasma levels of their
soluble forms in the umbilical cord blood in infants with documented chorioamnionitis.
Umbilical cord blood samples were obtained from 10 healthy term newborns,10 noninfected
preterm infants, 10 preterm infants with premature rupture of membranes and 9 preterm
infants with clinical and histological CA. The expression of CD40L and P-selectin
on platelets was 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 CA had significantly higher percentages of platelets expressing CD40L
in basal conditions (5.3 ± 2.9% vs. 1.6 ± 0.7% in non- infected preterm infants p < 0.05), while the percentages of Pselectin positive platelets were similar among
all groups. In contrast, 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 of sCD40L. As expected, the levels
of IL-6, a pro-inflammatory cytokine were significantly higher in samples obtained
from preterm neonates whose mothers had also elevated inflammatory parameters. Our
observations suggest that platelets are involved in the complex inflammatory pathogenesis
of CA. Neither P-selectin expression on cord blood platelets nor plasma sP-selectin
or sCD40L were suitable platelet markers in CA, whereas CD40L was significantly elevated
in histologically proven CA.
Keywords
Neonates - platelets - chorioamnionitis - CD40L