title: Respiratory virus detection in nasopharyngeal aspirate versus bronchoalveolar lavage is dependent on virus type in children with chronic respiratory symptoms.
abstract: BACKGROUND
  The comparative yield of respiratory virus detection from nasopharyngeal aspirate (NPA) versus bronchoalveolar lavage (BAL) is uncertain. Furthermore, the significance of virus detection and its relationship to lower airway neutrophilic inflammation is poorly studied.
  
  
  OBJECTIVE
  To evaluate the sensitivity, specificity and predictive values of NPA for detecting respiratory viruses in BAL; and to determine the relationship between viruses and lower airway neutrophilia in children with non-acute respiratory illness.
  
  
  METHODS
  150 paired NPA and BAL samples were obtained from 75 children aged <18 years undergoing flexible bronchoscopy for investigation of chronic respiratory symptoms. Viral studies were performed using polymerase chain reaction (PCR). Cellularity studies were performed on BALs. Diagnostic parameters of NPA compared to BAL and associations between viruses and lower airway %neutrophils were evaluated.
  
  
  RESULTS
  NPA had a higher yield than BAL for detection of any respiratory virus (52 versus 38, respectively). NPA had a high sensitivity (92%) and low specificity (57%) for detecting HRV in BAL with poor kappa agreement value of 0.398 (95% CI 0.218-0.578, p<0.001). NPA had a fair sensitivity (69%) and good specificity (90.3%) for detecting HAdV on BAL, kappa agreement was 0.561 (95% CI 0.321-0.801, p<0.001). HAdV positivity on NPA, compared to negativity, was independently associated with heightened airway neutrophilia [mean difference (95% CI): 18 (1,35); p=0.042].
  
  
  CONCLUSIONS
  NPA has a higher yield for respiratory virus detection than BAL, however its diagnostic accuracy is dependent on viral species. Adenovirus positivity is associated with significantly heightened lower airway neutrophilia in children with chronic respiratory symptoms.
authors.affiliation: Queensland Children's Medical Research Institute, The University of Queensland, Brisbane, Australia; Queensland Children's Respiratory Centre, Royal Children's Hospital, Brisbane, Australia. Electronic address: daniellewurzel@netspace.net.au.
authors.forename: Danielle F
authors.initials: DF
authors.lastname: Wurzel
authors.forename: Julie M
authors.initials: JM
authors.lastname: Marchant
authors.forename: Julia E
authors.initials: JE
authors.lastname: Clark
authors.forename: Ian M
authors.initials: IM
authors.lastname: Mackay
authors.forename: Claire Y T
authors.initials: CY
authors.lastname: Wang
authors.forename: Theo P
authors.initials: TP
authors.lastname: Sloots
authors.forename: John W
authors.initials: JW
authors.lastname: Upham
authors.forename: Stephanie T
authors.initials: ST
authors.lastname: Yerkovich
authors.forename: I Brent
authors.initials: IB
authors.lastname: Masters
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Baker
authors.forename: Sophie
authors.initials: S
authors.lastname: Anderson-James
authors.forename: Anne B
authors.initials: AB
authors.lastname: Chang
mesh_terms: D000256:Adenoviridae / Q000302:isolation & purification; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000821:virology*; D002675:Child, Preschool; D060085:Coinfection; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000821:virology*; D011446:Prospective Studies; D012044:Regression Analysis; D012141:Respiratory Tract Infections / Q000175:diagnosis* / Q000821:virology*; D012229:Rhinovirus / Q000302:isolation & purification; D014773:Virology / Q000379:methods
keywords: BAL; Bacteria; Co-infection; HAdV; HBoV; HCoV – NL63, OC43, 229E, HKU1; HPIV1–3; HRV; Human adenovirus; Human rhinovirus; IFAV; IFBV; KI polyomavirus; KIPyV; NPA; Neutrophilic airway inflammation; PCR; Polymerase chain reaction; RSV; RVI; WU polyomavirus; WUPyV; bronchoalveolar lavage; hMPV; human adenovirus; human bocavirus; human coronaviruses; human influenza A virus; human influenza B virus; human metapneumovirus; human para-influenza virus 1–3; human rhinovirus; nasopharyngeal aspirate; polymerase chain reaction; respiratory syncytial virus; respiratory virus infection