BACKGROUND: Human neutrophil lipocalin (HNL) has been used extensively to differentiate acute bacterial infection from febrile diseases as a biomarker to reflect the activation of the neutrophil. The serum HNL levels in the adult-onset Still's disease (AOSD) patients with and without infection, as well as the healthy controls (HCs), were analyzed statistically in this study to evaluate the value of HNL for the diagnosis of AOSD. METHODS: A total of 129 AOSD patients were enrolled, from whom blood samples were drawn and the AOSD diagnosis was confirmed through the review of the medical records, where the systemic score, demographic characteristics, clinical manifestations, and laboratory parameters were also collected for the patients; in addition, a total of 40 HCs were recruited among the blood donors from the healthcare center with the relevant information collected. The HNL test was done for the blood samples with the enzyme-linked immunosorbent assay and the analyses were done for the correlations of HNL with clinical manifestations and diagnostic effectiveness. RESULTS: The serum HNL increased significantly in the patients with only AOSD as compared with that in the HCs (139.76 ± 8.99 ng/mL vs . 55.92 ± 6.12 ng/mL; P  < 0.001). The serum HNL level was correlated with the white blood cell (WBC) count ( r  = 0.335, P  < 0.001), neutrophil count ( r  = 0.334, P  < 0.001), erythrocyte sedimentation rate ( r  = 0.241, P  = 0.022), C-reactive protein ( r  = 0.442, P  < 0.0001), and systemic score ( r  = 0.343, P  < 0.0001) in the AOSD patients significantly. Patients with fever, leukocytosis ≥15,000/mm 3 , and myalgia in the HNL-positive group were observed relatively more than those in the HNL-negative group ( P  = 0.009, P  = 0.023, and P  = 0.007, respectively). HNL was a more sensitive indicator than ferritin and C-reactive protein (CRP) to differentiate the AOSD patients with bacterial infection from AOSD-only patients, and the Youden index was 0.6 for HNL and 0.29 for CRP. CONCLUSION Serum HNL can be used as a biomarker for the diagnosis of the AOSD, and HNL is also observed to be associated with the disease activity.
Adult ; Humans ; Still's Disease, Adult-Onset/diagnosis* ; C-Reactive Protein/metabolism* ; Neutrophils/metabolism* ; Clinical Relevance ; Biomarkers ; Bacterial Infections

PURPOSE: To investigate clinical implications of delta neutrophil index (DNI) to discriminate adult onset Still's disease (AOSD) from sepsis. MATERIALS AND METHODS: We reviewed the medical records of 13 patients with AOSD and 33 gender and age-matched patients with sepsis. In all subjects, microbial tests were performed to exclude or confirm sepsis. All laboratory data were measured two or three times during the first 3 days and represented by their mean levels. DNI was measured automatically by ADVIA 2120 for the first 3 days. RESULTS: There were no significant differences in white blood cell counts, neutrophil proportion, erythrocyte sedimentation rate and C-reactive protein between two groups. AOSD patients had notably lower DNI than sepsis patients regardless of the presence of bacteremia or not. However, both DNI and ferritin were not significant independent factors for predicting sepsis in the multivariate logistic regression analysis. Meanwhile, the area under the receiver operating characteristic curve (AUROC) of DNI was slightly higher than that of ferritin. When we set DNI of 2.75% as the cut-off value for predicting sepsis, 11 (84.6%) of AOSD patients had a DNI value below 2.75% and 2 (15.4%) of them had a DNI over 2.75% (relative risk for sepsis 176). CONCLUSION: We suggest that DNI may be a useful marker for differential diagnosis of AOSD from sepsis in the early phase as supplementary to ferritin.
Adult ; Biological Markers/*metabolism ; Diagnosis, Differential ; Female ; Humans ; Male ; Middle Aged ; Neutrophils/*metabolism ; Retrospective Studies ; Sepsis/*diagnosis/metabolism ; Still's Disease, Adult-Onset/*diagnosis/metabolism