Relationship between early-onset neonatal sepsis and the level of interleukin-6, C-reactive protein in umbilical cord serum of the newborns with premature rupture of membrane

Abstract

Objective To study the levels of interleukin-6(IL-6) and C-reactive protein(CRP)in umbilical cord serum of the newborns with premature rupture of membrane(PROM)and to explore the value of IL-6 and CRP in the diagnosis of early onset neonatal sepsis(EONS). Method A total of 187 term newborns with PROM>12 h who were born normal vaginally in our Hospital from April 2015 to December 2015 were enrolled in this study as the PROM group and another 50 term infants without PROM and infection as the control group. The levels of IL-6 and CRP in umbilical cord serum were quantified by ELISA, the results of which were compared between groups. Receiver operating characteristics (ROC) curves were drawn to find out the cut-off value of IL-6 and CRP for the diagnosis of EONS. Result The levels of IL-6 and CRP in umbilical cord serum in the PROM group were significantly higher than those in the control group [IL-6 20.3(9.5, 35.8)pg/ml vs.9.3(6.9, 27.5)pg/ml, CRP 0.42(0.25, 0.78)mg/L vs.0.33(0.18, 0.45)mg/L, P<0.05]. The levels of IL-6 and CRP in the newborns whose mother had chorioamnionitis were significantly higher than those in the newborns whose mother was without chorioamnionitis [IL-6 62.5(35.2, 92.7)pg/ml vs.10.8(9.3, 33.4)pg/ml, CRP 0.86(0.44, 1.95)mg/L vs.0.35(0.20, 0.62)mg/L, P<0.05]. The levels of IL-6 and CRP in the infants with PROM≥18 h was significantly higher than those in the infants with PROM<18 h [IL-6 32.1(9.9, 42.2)pg/ml vs.10.7(9.2, 32.6)pg/ml, CRP 0.44(0.29, 0.86)mg/L vs.0.35(0.23, 0.61)mg/L, P<0.05]. The levels of IL-6 and CRP in the neonates with EONS was significantly higher than those in the neonates without EONS [IL-6 92.0(58.3, 161.0)pg/ml vs.20.0(9.4, 35.2)pg/ml, CRP 1.94(0.47, 2.73)mg/L vs. 0.38(0.24, 0.67)mg/L, P<0.05]. ROC curve analysis showed that the cut-off value of IL-6 and CRP for the diagnosis of EONS were 81.1pg/ml (sensitivity 76.5%, specificity 90.6%) and 1.88mg/L (sensitivity 64.7%, specificity 89.4%). With the combination of IL-6 and CRP levels, the sensitivity was 88.2% and the specificity was 84.1% for the diagnosis of EONS. Conclusion To measure the IL-6 and CRP levels in umbilical cord serum is helpful for the early diagnosis of EONS, and the combined detection of the 2 items may improve the sensitivity of diagnosis. Key words: Premature rupture of membrane; Chorioamnionitis; Interleukin-6; C-reactive protein; Early onset neonatal sepsis