Serum measurements of human neutrophil lipocalin (HNL) discriminate between acute bacterial and viral infections

Abstract

Human neutrophil lipocalin (HNL) is a recently identified protein from human neutrophil granules. The concentrations of HNL in the circulation were measured, in a group of patients with acute infections, using a radioimmunoassay. The concentrations of HNL in patients infected by viruses and bacteria were 93.78±45.30 μg 1^-1 (SD), 404.14±355.02 μg 1^-1 (SD) in serum, and 47.81±18.18 μg 1^-1 (SD), 145.46±194.32 μg 1^-1 (SD) in plasma, respectively. The differences between the two patient groups were highly significant. There was a significant correlation between serum HNL and plasma HNL levels in bacterial infections (r = 0.73, p-1 (HNL in serum), the positive and negative predictive values for the diagnosis of bacterial infections were 92 and 96%, respectively, which were superior to the optimal predictive values of CRP. Thus, the determination of HNL level is useful in the diagnosis of acute bacterial infections.