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.