title: Upper-respiratory viral infection, biomarkers, and COPD exacerbations.
abstract: BACKGROUND
  Respiratory viruses frequently are recovered in the upper-respiratory tract during acute exacerbations of COPD (AECOPD), but their role as contributing pathogens remains unclear. The usefulness of procalcitonin and C-reactive protein as indicators of the presence or absence of viral infection in this setting also needs to be evaluated.
  
  
  METHODS
  The study was of a prospective cohort of patients with COPD admitted to the ED for AECOPD. Reverse transcriptase-polymerase chain reaction (RT-PCR) for 14 respiratory viruses was performed on nasopharyngeal swabs collected at admission and after recovery in stable condition.
  
  
  RESULTS
  Eighty-six patients (mean age, 72 years; male, 64%) were included. During AECOPD, upper-respiratory viral infections were detected in 44 (51%) patients: picornavirus in 22, metapneumovirus in seven, coronavirus in eight, influenza A/B in two, parainfluenza in two, and respiratory syncytial virus in three. A dual infection was present in three patients. After recovery, viruses were detected in only eight (11%) of 71 patients (P < .001 compared with AECOPD phase). In five of these patients, no virus had been identified during the initial exacerbation, thus suggesting a new viral infection acquired during follow-up. During AECOPD, procalcitonin and C-reactive protein levels did not differ significantly between patients with or without a proven viral infection.
  
  
  CONCLUSIONS
  Prevalence of upper-respiratory viral infection, as detected from nasopharyngeal swab by RT-PCR, is high in AECOPD and low after clinical recovery, suggesting that AECOPD frequently are triggered by viral infections initiated in the upper-respiratory tract. In our study, serum procalcitonin and C-reactive protein did not discriminate virus-associated exacerbations from others.
  
  
  BACKGROUND
  clinicaltrials.gov; Identifier: NCT00448604.
authors.affiliation: Department of Internal Medicine, Geneva's University Hospitals and University of Geneva, Geneva, Switzerland. omarkherad@gmail.com
authors.forename: Omar
authors.initials: O
authors.lastname: Kherad
authors.forename: Laurent
authors.initials: L
authors.lastname: Kaiser
authors.forename: Pierre-Olivier
authors.initials: PO
authors.lastname: Bridevaux
authors.forename: François
authors.initials: F
authors.lastname: Sarasin
authors.forename: Yves
authors.initials: Y
authors.lastname: Thomas
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Janssens
authors.forename: Olivier T
authors.initials: OT
authors.lastname: Rutschmann
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D002097:C-Reactive Protein / Q000378:metabolism*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000821:virology*; D012141:Respiratory Tract Infections / Q000097:blood / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide