title: Elevated expression of both mRNA and protein levels of IL-17A in sputum of stable Cystic Fibrosis patients.
abstract: BACKGROUND
  T helper 17 (Th17) cells can recruit neutrophils to inflammatory sites through production of IL-17, which induces chemokine release. IL-23 is an important inducer of IL-17 and IL-22 production. Our aim was to study the role of Th17 cells in cystic fibrosis (CF) lung disease by measuring IL-17 protein and mRNA levels and IL-22 and IL-23 mRNA in sputum of clinically stable CF patients and by comparing these levels with healthy controls.
  
  
  METHODS
  Sputum induction was performed in adult CF patients outside of an exacerbation and healthy control subjects. IL-17A protein levels were measured in supernatants with cytometric bead array (CBA) and RNA was isolated and quantitative RT-PCR was performed for IL-17A, IL-22 and IL-23.
  
  
  RESULTS
  We found significantly higher levels of IL-17A protein and mRNA levels (both: p < 0.0001) and IL-23 mRNA levels (p < 0.0001) in the sputum of CF group as compared to controls. We found very low levels of IL-22 mRNA in the CF group. The levels of IL-17 and IL-23 mRNA were higher in patients chronically infected with Pseudomonas aeruginosa (P. aeruginosa) as compared to those who were not chronically infected with P. aeruginosa. The presence of Staphylococcus aureus (S. aureus) on sputum did not affect the IL-17 or IL-23 levels. There was no correlation between IL-17 or IL-23 levels and FEV1 nor sputum neutrophilia.
  
  
  CONCLUSIONS
  The elevated levels of IL-17 and IL-23 might indicate that Th17 cells are implicated in the persistent neutrophil infiltration in CF lung disease and chronic infection with P. aeruginosa.
authors.affiliation: Laboratory of Pneumology, KULeuven, Herestraat, Leuven, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Decraene
authors.forename: Anna
authors.initials: A
authors.lastname: Willems-Widyastuti
authors.forename: Ahmad
authors.initials: A
authors.lastname: Kasran
authors.forename: Kris
authors.initials: K
authors.lastname: De Boeck
authors.forename: Dominique M
authors.initials: DM
authors.lastname: Bullens
authors.forename: Lieven J
authors.initials: LJ
authors.lastname: Dupont
mesh_terms: D000328:Adult; D003550:Cystic Fibrosis / Q000378:metabolism*; D005260:Female; D006801:Humans; D020381:Interleukin-17 / Q000378:metabolism*; D053759:Interleukin-23 / Q000378:metabolism*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism*; D013183:Sputum / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C508717:IL17A protein, human; D020381:Interleukin-17; D053759:Interleukin-23; D012333:RNA, Messenger