The Correlation of Antibacterial Peptides Concentration in Umbilical Cord Blood and Early Onset Sepsis in Preterm Infants

Umbilical cord blood from singleton preterm infants was collected during delivery, and the concentration of LL37 was measured. C-reactive protein (CRP), white blood cell count (WBC), platelets (PLT), and mean platelet volume (MPV) were determined within 3 days after birth. The differences in LL37, CRP, WBC, PLT, and MPV levels between the two groups were compared. Pearson correlation method was used to analyze the correlation between these factors. The early individual value of each detected index for early onset sepsis was analyzed by ROC curve. The level of LL37 in umbilical cord blood of sepsis group was significantly higher than those in the control group (383.85 +/- 46.71 vs. 252.37 +/- 83.30 ng/ml). Meanwhile, the levels of CRP, WBC, and MPV in the sepsis group were significantly higher than those in the control group (CRP:5.73 +/- 4.19 vs. 2.50 +/- 2.77 mg/L; WBC: 13.47 +/- 12.35 vs. 6.83 +/- 3.55 x 10(9)/L; MPV: 11.20 +/- 1.11 vs. 8.90 +/- 0.68 fL), the level of PLT was significantly lower than those in the control group (PLT: 161.00 +/- 38.51 vs. 241.50 +/- 49.85 x 10(9)/L) (P < 0.05). Pearson correlation analysis showed that the expression of LL37 was negatively correlated with PLT level (r = -0.9347, P < 0.0001), and positively correlated with MPV level (r = 0.9463, P < 0.0001). ROC curve analysis showed that the area under curve of LL37 for diagnosis of early onset sepsis was 0.875, the prediction probability was 0.7, the sensitivity was 90.0% and the specificity was 80.0%.

Automated summary

Umbilical cord blood levels of LL37 were found to be associated with early onset sepsis in preterm infants. Additionally, levels of CRP, WBC, PLT, and MPV were also correlated with the occurrence of sepsis. The expression of LL37 was negatively correlated with platelet count and positively correlated with mean platelet volume. LL37 showed a high accuracy in diagnosing early onset sepsis.