title: Small macrophages are present in early childhood respiratory disease.
abstract: BACKGROUND
  Recently, an established "small macrophage" phenotype has been observed in the sputum of patients with CF and COPD. However, little is known about the prevalence of this phenotype in the airways of young children. Since respiratory inflammation begins early in CF, we hypothesised that these small macrophages would be increased in paediatric CF bronchoalveolar lavage (BAL).
  
  
  METHODS
  Macrophage populations in CF and disease control BAL were assessed by multicolour flow cytometry. BAL inflammatory indices were collected as part of the AREST-CF programme.
  
  
  RESULTS
  Small macrophages were present in CF (n=35, mean 36±12% of BAL macrophages) but not significantly different to the respiratory disease controls (n=7, mean 40±21%). Number of small macrophages correlated significantly with number of BAL neutrophils (r=0.44, p<0.01) but not infection or IL-8.
  
  
  CONCLUSIONS
  In paediatric patients small macrophages are not unique to CF, but their establishment as the dominant phenotype in adults may be due to chronicity of inflammation and infection.
authors.affiliation: Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, Perth, Australia, 6008. lgarratt@ichr.uwa.edu.au
authors.forename: Luke W
authors.initials: LW
authors.lastname: Garratt
authors.forename: Adam K A
authors.initials: AK
authors.lastname: Wright
authors.forename: Sarath C
authors.initials: SC
authors.lastname: Ranganathan
authors.forename: Jonathan
authors.initials: J
authors.lastname: Grigg
authors.forename: Peter D
authors.initials: PD
authors.lastname: Sly
mesh_terms: D000367:Age Factors; D018893:Bronchoalveolar Lavage; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology*; D001999:Bronchoscopy; D048429:Cell Size; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007958:Leukocyte Count; D016676:Macrophages, Alveolar / Q000473:pathology*; D008297:Male; D012140:Respiratory Tract Diseases / Q000378:metabolism / Q000473:pathology*; D013183:Sputum / Q000166:cytology*