Neutrophil CD64 as a Diagnostic Marker of Sepsis in Neonates

BACKGROUND: Sepsis in neonates hospitalized in the neonatal intensive care unit is a global problem and is a significant contributor to morbidity and mortality. Neutrophil surface CD64, the high-affinity Fc receptor, is quantitatively up-regulated during infection and sepsis. OBJECTIVE: Our goal in this prospective study was to measure the neutrophil CD64 in blood as an adjunct to our previously validated hematologic scoring system for detecting neonatal sepsis. METHODS: A prospective study enrolled newborns with documented sepsis (n = 25), clinical sepsis (n = 25), and control newborns (n = 25). C-reactive protein, neutrophil CD64, complete blood counts, and blood cultures were taken. Neutrophil CD64 was analyzed by flow cytometry. RESULTS: CD64 was significantly elevated in the groups with documented and clinical sepsis (P < 0.001). CD64 had a sensitivity of 96%, a specificity of 100%, a positive predictive value of 96.2%, and a negative predictive value of 100% with a cutoff value of 45.8% and 46.0% in the confirmed and the clinical sepsis groups, respectively. CONCLUSIONS: CD64 expression on neutrophils increases significantly in neonates with sepsis and can be considered a useful diagnostic marker for early diagnosis of neonatal infection as a single determination compared with other inflammatory markers.