RESUMO
PURPOSE: 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). CONCLUSION: 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.
