In newborns with congenital pneumonia, the natural antimicrobial peptide LL‑37 was much higher while vitamin D levels were lower than in healthy babies. Higher LL‑37 linked to poorer early health scores and longer hospital stays, and a level above 17 pg/mmol could reliably flag the infection.

To evaluate the diagnostic value of anti-microbial peptide (cathelicidin), LL-37, in congenital pneumonia and its relation to 25 hydroxycholecalciferol [(25 OH)D] status. The study included 30 neonates with congenital pneumonia and culture proven sepsis admitted to neonatal intensive care unit of Ain Shams University and 30 healthy neonates as control group. All neonates were subjected to history taking, clinical examination and measurement of serum 25(OH)D and cathelicidin. Neonates with congenital pneumonia had significantly higher serum cathelicidin and lower serum 25(OH)D compared to controls. Serum cathelicidin was negatively correlated with Apgar score at 1 and 5 min and positively correlated with length of stay among patient group. Cut-off value of cathelicidin to diagnose congenital pneumonia was 17 pg/mmol with 93% sensitivity and 86% specificity. Neonates with congenital pneumonia had significantly high cathelicidin and low 25(OH)D suggesting a possible role of fetal 25(OH)D deficiency as predisposing factor for congenital pneumonia.