Serum calprotectin as a diagnostic marker of late onset sepsis in full-term neonates

Abstract

Background: Calprotectin, a complex of two calcium-binding proteins that belong to the S100 protein family, is abundant in the cytosolic fraction of neutrophils. A high level of calprotectin reportedly exists in extracellular fluid during various inflammatory conditions, but its role in neonatal sepsis was investigated only in one study as a marker of sepsis in very low birth weight neonates. Objective: This study aimed to measure the serum calprotectin level by ELISA in full-term neonates with late onset neonatal sepsis, its correlations with other laboratory markers of sepsis as interleukin-6, C-reactive protein (CRP), total leucocytic count and platelet count and its relation to the outcome of cases. Methods: This study comprised 48 full-term neonates with gestational ages of 37 to 42 weeks with manifestations of late onset neonatal sepsis admitted to the neonatal intensive care unit, Minia University Hospital during the period from February, 2011 to December, 2011 and 40 healthy neonates, age and sex matched as a control group. Serum levels of calprotectin, IL6 and CRP were measured for all neonates recruited in this study. Results: Serum calprotectin levels were significantly higher in term neonates with late onset neonatal sepsis than controls (3.77±1.85 μg/ml and 0.70±0.33 μg/ml respectively, P-value = 0.000). Cases with positive blood cultures and poor outcomes had the highest levels of calprotectin (5.8±0.61 μg/ml and 6.1±0.42 μg/ml respectively). Significant positive correlations were found between calprotectin levels and IL6 (P-value =0.000, r=0.92), C-reactive protein (p=0.000,r=0.95) and total leucocytic count (P-value =0.000, r=0.72), and negative correlations were found between its level and platelet count (P-value =0.000, r=-0.87), gestational age (P-value =0.014, r=-0.35) and body weight (P-value=0.018, r=-0.34). No significant differences were observed between males and females as regards calprotectin levels (3.96±2.10 μg/ml vs 3.55±1.52 μg/ml, P-value=0.444). Conclusions: Serum calprotectin levels are significantly higher in full-term neonates with late onset neonatal sepsis. Its levels correlated well with other laboratory markers of sepsis and neonatal mortality. It is a sensitive diagnostic marker for late onset neonatal sepsis.

Keywords: Calprotectin, IL6, Full-term, Late-onset sepsis

Egypt J Pediatr Allergy Immunol 2012;10(1):19-24