Serum Apolipoprotein A and Apolipoprotein B as Diagnostic Biomarkers of Neonatal Sepsis in Egyptian Full-term and Premature Neonates

INTRODUCTION: Neonatal sepsis (NS) is a leading cause of morbidity and mortality in newborns, particularly in developing countries, where early and accurate diagnosis remains challenging. Conventional sepsis markers, such as C-reactive protein (CRP) and hematological indices, lack sensitivity and specificity. This study aimed to evaluate serum apolipoproteinA (Apo A) and apolipoprotein B (Apo B) as potential diagnostic biomarkers in neonatal sepsis. METHODS: This case-control study included 160 neonates with sepsis (confirmed by clinical assessment, sepsis screening, and blood culture) and 80 healthy neonates as controls. Patients were classified by sepsis severity (sepsis vs. severe sepsis) and onset (early vs. late). Serum Apo A and Apo B titres were measured using an enzyme-linked immunosorbent assay. RESULTS: Serum Apo A was significantly lower in septic neonates than in controls (p < 0.001), with the lowest titres observed in severe sepsis. Apo B was significantly elevated in septic neonates, particularly in severe cases (p < 0.001). Apo A, at a cut-off of ≤57.6 mg/dL, yielded 80% sensitivity, 90% specificity, and an area under the curve (AUC) of 0.939, whereas Apo B, at a cut-off of >7.98 mg/dL, yielded 99.4% sensitivity, 75% specificity, and an AUC of 0.998. Apo A negatively correlated with hematocrit, WBC count, and neutrophil shift, while Apo B showed a negative correlation with hematocrit (p < 0.05). DISCUSSION: Data suggest that the relationship between apolipoprotein levels and sepsis can also provide insights into inflammatory pathways associated with neonatal infections. Increased understanding of these pathways can inform the therapeutic approaches, in which the modulation of lipid metabolism becomes fundamental to managing sepsis results. Therefore, the incorporation of monitoring Apo A and Apo B levels can serve as pragmatic biomarkers to evaluate not only the presence of sepsis but also the potential response to treatment protocols, thus advancing the path toward Personalized Medicine in the Neonatal Intensive Care Unit. CONCLUSION: Serum Apo A and Apo B titres are valuable adjunct diagnostic markers for NS. Apo A reduction reflects the acute-phase response, while Apo B elevation may indicate altered lipid metabolism in severe infection.