title: Measurement of soluble perforin, a marker of CD8+ T lymphocyte activation in epithelial lining fluid.
abstract: BACKGROUND
  CD8(+) T lymphocytes in the peripheral airways have been suggested to be involved in the pathogenesis of COPD. However, the significance of CD8(+) T lymphocyte activation in COPD is not well understood. A biomarker of CD8(+) T lymphocyte activation in patients with COPD is required.
  
  
  METHODS
  Thirty COPD patients and twenty-one healthy controls (eleven ex-smokers and ten who had never smoked or were light ex-smokers) were included in this study. We separately obtained epithelial lining fluid (ELF) from central and peripheral airways using a bronchoscopic microsampling technique. Levels of perforin in ELF were measured and we examined correlations between its values and patients characteristics including pulmonary function.
  
  
  RESULTS
  Perforin levels in both the central and peripheral airways in COPD patients were significantly higher than those in the healthy control groups. In the healthy control groups, there was no significant difference in perforin levels between central and peripheral airways. However, in COPD patients, perforin levels in peripheral airways were significantly higher than those in central airways. Perforin levels in peripheral airways were significantly correlated with FEV(1) (percent predicted), FEV(1)/FVC, and DLco (percent predicted) in COPD patients.
  
  
  CONCLUSIONS
  The microsampling technique is safe and useful for separately obtaining ELF from central and peripheral airways. Levels of perforin in ELF from peripheral airways were significantly increased and correlated with the degree of pulmonary dysfunction. Perforin might reflect inflammation involving CD8(+) T-lymphocytes. This novel biomarker might enable better understanding of the pathogenesis of COPD.
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka 545-8585, Japan. nahoko22@med.osaka-cu.ac.jp
authors.forename: Nahoko
authors.initials: N
authors.lastname: Shiratsuchi
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Asai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kanazawa
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kyoh
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tochino
authors.forename: Toyoki
authors.initials: T
authors.lastname: Kodama
authors.forename: Kazuto
authors.initials: K
authors.lastname: Hirata
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D001999:Bronchoscopy; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D054353:Perforin / Q000378:metabolism*; D029424:Pulmonary Disease, Chronic Obstructive / Q000276:immunology* / Q000473:pathology; D020545:Respiratory Mucosa / Q000276:immunology* / Q000473:pathology; D012907:Smoking / Q000276:immunology* / Q000473:pathology; D014797:Vital Capacity
chemical_list: D015415:Biomarkers; D054353:Perforin