title: Neutrophil CD64 Expression as a Diagnostic Marker in Patients Hospitalized with Exacerbations of COPD: A Prospective Observational Study.
abstract: OBJECTIVE
  The expression of the neutrophil high-affinity Fc-gamma receptor (CD64) can be used as a diagnostic marker for bacterial infection and sepsis. The aims of this study were to determine the diagnostic accuracy of CD64 compared to C-reactive protein (CRP) and white blood cell count (WBC) in patients hospitalized with acute exacerbations of COPD (AECOPD) and to investigate the kinetics of CD64 expression.
  
  
  METHODS
  The present study is a prospective, single-centre observation study. Blood samples were collected from patients hospitalized with AECOPD at admission and after 6, 24 and 48 h. Retrospective reviews on the patients' medical records were performed blinded to the CD64 results. The CD64 was measured using the Leuko64 kit from Trillium Diagnostics, LLC (Maine, USA) with the CELL-DYN Sapphire Haematology System (Abbott Laboratories, Illinois, USA). Diagnostic accuracy of the CD64, CRP and WBC was compared using a receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  A total of 113 patients were included. Thirty-six patients (32 %) had pulmonary infiltrate on chest X-ray at admission (PI). The CD64 was higher in samples from patients with AECOPD and PI than those without PI at admission (median 1.25 vs. 0.60, p = 0.002) and during 48 h of follow-up. The area under the ROC curve of CD64, CRP and WBC was 0.69, 0.73 and 0.64, respectively, (p = 0.42 for the test of difference).
  
  
  CONCLUSIONS
  Neutrophil CD64 expression has about the same diagnostic accuracy as CRP in diagnosing pneumonia in patients hospitalized with AECOPD, but does not add to the diagnostic accuracy of CRP and WBC count.
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7006, Trondheim, Norway. elena.titova@ntnu.no.|Department of Thoracic Medicine, Trondheim University Hospital, 7006, Trondheim, Norway. elena.titova@ntnu.no.
authors.forename: Elena
authors.initials: E
authors.lastname: Titova
authors.affiliation: Department of Immunology and Transfusion Medicine, Trondheim University Hospital, 7006, Trondheim, Norway. Marthe.Wedo.Aune@stolav.no.
authors.forename: Marthe Wedø
authors.initials: MW
authors.lastname: Aune
authors.affiliation: Department of Immunology and Transfusion Medicine, Trondheim University Hospital, 7006, Trondheim, Norway. Kristin.Fonn@stolav.no.
authors.forename: Kristin
authors.initials: K
authors.lastname: Fonn
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7006, Trondheim, Norway. Anne.H.Henriksen@ntnu.no.|Department of Thoracic Medicine, Trondheim University Hospital, 7006, Trondheim, Norway. Anne.H.Henriksen@ntnu.no.
authors.forename: Anne Hildur
authors.initials: AH
authors.lastname: Henriksen
authors.affiliation: Department of Clinical Chemistry, Trondheim University Hospital, Trondheim, 7006, Norway. Arne.Aasberg@stolav.no.
authors.forename: Arne
authors.initials: A
authors.lastname: Åsberg
mesh_terms: D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D060085:Coinfection / Q000097:blood / Q000175:diagnosis; D018450:Disease Progression; D005260:Female; D006760:Hospitalization; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D009504:Neutrophils / Q000378:metabolism; D018410:Pneumonia, Bacterial / Q000097:blood* / Q000175:diagnosis* / Q000382:microbiology; D011024:Pneumonia, Viral / Q000097:blood* / Q000175:diagnosis*; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000503:physiopathology; D012372:ROC Curve; D017452:Receptors, IgG / Q000097:blood*; D013183:Sputum / Q000382:microbiology; D013997:Time Factors
chemical_list: D015415:Biomarkers; D017452:Receptors, IgG; D002097:C-Reactive Protein
keywords: Biomarkers; COPD exacerbation; Diagnostic accuracy; Infection; Neutrophil CD64 expression