Serum Soluble Programmed Death Ligand-1 (sPD-L1) as a Diagnostic Marker in Neonatal Sepsis

To evaluate serum soluble programmed death ligand-1 (sPD-L1) levels in neonatal sepsis and assess its diagnostic performance, association with disease severity, and clinical outcomes.

This prospective observational study was conducted in a tertiary-care neonatal intensive care unit. Neonates with suspected sepsis, defined according to National Neonatology Forum (NNF) 2021 guidelines, were enrolled after parental consent. Serum sPD-L1 levels were measured using enzyme-linked immunosorbent assay (ELISA). Comparisons were performed across early-onset and late-onset sepsis, culture-positive and culture-negative sepsis, presence of multi-organ dysfunction syndrome (MODS), and survival outcomes. Receiver operating characteristic (ROC) curve analysis was used to determine diagnostic accuracy.

Serum sPD-L1 levels were significantly elevated in neonates with sepsis. Higher levels were observed in early-onset sepsis, culture-positive sepsis, neonates with MODS, and non-survivors, indicating a positive association with disease severity and adverse outcomes. ROC analysis demonstrated good diagnostic performance, with an area under the curve of 0.86. A cut-off value of 85 pg/mL showed clinically meaningful diagnostic discrimination.

Serum sPD-L1 is significantly elevated in neonatal sepsis and correlates with severity, organ dysfunction, and mortality. It may serve as a promising adjunct biomarker for early diagnosis and risk stratification in neonatal sepsis, warranting validation in larger multicentric studies.