title: CD8 positive T cells express IL-17 in patients with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) is a progressive and irreversible chronic inflammatory disease of the lung. The nature of the immune reaction in COPD raises the possibility that IL-17 and related cytokines may contribute to this disorder. This study analyzed the expression of IL-17A and IL-17F as well as the phenotype of cells producing them in bronchial biopsies from COPD patients.
  
  
  METHODS
  Bronchoscopic biopsies of the airway were obtained from 16 COPD subjects (GOLD stage 1-4) and 15 control subjects. Paraffin sections were used for the investigation of IL-17A and IL-17F expression in the airways by immunohistochemistry, and frozen sections were used for the immunofluorescence double staining of IL-17A or IL-17F paired with CD4 or CD8. In order to confirm the expression of IL-17A and IL-17F at the mRNA level, a quantitative RT-PCR was performed on the total mRNA extracted from entire section or CD8 positive cells selected by laser capture microdissection.
  
  
  RESULTS
  IL-17F immunoreactivity was significantly higher in the bronchial biopsies of COPD patients compared to control subjects (P < 0.0001). In the submucosa, the absolute number of both IL-17A and IL-17F positive cells was higher in COPD patients (P < 0.0001). After adjusting for the total number of cells in the submucosa, we still found that more cells were positive for both IL-17A (P < 0.0001) and IL-17F (P < 0.0001) in COPD patients compared to controls. The mRNA expression of IL-17A and IL-17F in airways of COPD patients was confirmed by RT-PCR. The expression of IL-17A and IL-17F was co-localized with not only CD4 but also CD8, which was further confirmed by RT-PCR on laser capture microdissection selected CD8 positive cells.
  
  
  CONCLUSIONS
  These findings support the notion that Th17 cytokines could play important roles in the pathogenesis of COPD, raising the possibility of using this mechanism as the basis for novel therapeutic approaches.
authors.affiliation: Meakins-Christie Laboratories and Respiratory Division, Department of Medicine McGill University, 3626 rue St, Urbain, Montreal, QC, H2X 2P2 Canada.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chang
authors.forename: Jessica
authors.initials: J
authors.lastname: Nadigel
authors.forename: Nicholas
authors.initials: N
authors.lastname: Boulais
authors.forename: Jean
authors.initials: J
authors.lastname: Bourbeau
authors.forename: François
authors.initials: F
authors.lastname: Maltais
authors.forename: David H
authors.initials: DH
authors.lastname: Eidelman
authors.forename: Qutayba
authors.initials: Q
authors.lastname: Hamid
mesh_terms: D000328:Adult; D001706:Biopsy; D001980:Bronchi / Q000276:immunology*; D001999:Bronchoscopy; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D020381:Interleukin-17 / Q000032:analysis* / Q000235:genetics; D007834:Lasers; D008297:Male; D042282:Microdissection / Q000295:instrumentation; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000235:genetics / Q000276:immunology*; D011792:Quebec; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012720:Severity of Illness Index
chemical_list: C508717:IL17A protein, human; C440021:IL17F protein, human; D020381:Interleukin-17; D012333:RNA, Messenger