title: Identification of genes expressed by human airway eosinophils after an in vivo allergen challenge.
abstract: BACKGROUND
  The mechanism for the contribution of eosinophils (EOS) to asthma pathophysiology is not fully understood. Genome-wide expression analysis of airway EOS by microarrays has been limited by the ability to generate high quality RNA from sufficient numbers of airway EOS.
  
  
  OBJECTIVE
  To identify, by genome-wide expression analyses, a compendium of expressed genes characteristic of airway EOS following an in vivo allergen challenge.
  
  
  METHODS
  Atopic, mild asthmatic subjects were recruited for these studies. Induced sputum was obtained before and 48h after a whole lung allergen challenge (WLAC). Individuals also received a segmental bronchoprovocation with allergen (SBP-Ag) 1 month before and after administering a single dose of mepolizumab (anti-IL-5 monoclonal antibody) to reduce airway EOS. Bronchoalveolar lavage (BAL) was performed before and 48 h after SBP-Ag. Gene expression of sputum and BAL cells was analyzed by microarrays. The results were validated by qPCR in BAL cells and purified BAL EOS.
  
  
  RESULTS
  A total of 299 transcripts were up-regulated by more than 2-fold in total BAL cells following SBP-Ag. Mepolizumab treatment resulted in a reduction of airway EOS by 54.5% and decreased expression of 99 of the 299 transcripts. 3 of 6 post-WLAC sputum samples showed increased expression of EOS-specific genes, along with the expression of 361 other genes. Finally, the intersection of the 3 groups of transcripts (increased in BAL post SBP-Ag (299), decreased after mepolizumab (99), and increased in sputum after WLAC (365)) was composed of 57 genes characterizing airway EOS gene expression.
  
  
  CONCLUSIONS
  We identified 57 genes that were highly expressed by BAL EOS compared to unseparated BAL cells after in vivo allergen challenge. 41 of these genes had not been previously described in EOS and are thus potential new candidates to elucidate EOS contribution to airway biology.
authors.affiliation: Department of Medicine, Allergy, Pulmonary, and Critical Care Medicine Division, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA. sesnault@medicine.wisc.edu
authors.forename: Stephane
authors.initials: S
authors.lastname: Esnault
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Kelly
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Schwantes
authors.forename: Lin Ying
authors.initials: LY
authors.lastname: Liu
authors.forename: Larissa P
authors.initials: LP
authors.lastname: DeLain
authors.forename: Jami A
authors.initials: JA
authors.lastname: Hauer
authors.forename: Yury A
authors.initials: YA
authors.lastname: Bochkov
authors.forename: Loren C
authors.initials: LC
authors.lastname: Denlinger
authors.forename: James S
authors.initials: JS
authors.lastname: Malter
authors.forename: Sameer K
authors.initials: SK
authors.lastname: Mathur
authors.forename: Nizar N
authors.initials: NN
authors.lastname: Jarjour
mesh_terms: D000485:Allergens / Q000008:administration & dosage; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D001249:Asthma / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D004804:Eosinophils / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D055106:Genome-Wide Association Study; D006801:Humans; D015848:Interleukin-5 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology; D007958:Leukocyte Count; D008168:Lung / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D058977:Molecular Sequence Annotation; D012333:RNA, Messenger / Q000235:genetics / Q000276:immunology*; D013183:Sputum / Q000737:chemistry / Q000166:cytology
chemical_list: D000485:Allergens; D061067:Antibodies, Monoclonal, Humanized; C508599:IL5 protein, human; D015848:Interleukin-5; D012333:RNA, Messenger; C434107:mepolizumab