title: Tc2 response at the onset of COPD exacerbations.
abstract: BACKGROUND
  T lymphocytes and especially the subpopulations of CD8+ cells are believed to have a key role in COPD pathophysiology, but there are only few data regarding the role of these cells in COPD exacerbation.
  
  
  OBJECTIVE
  We aimed to study prospectively changes of CD8+ T-lymphocyte subpopulations in the sputum of COPD patients at the onset of mild exacerbations and at a stable condition in order to provide further insight in the pathophysiology of the disease.
  
  
  METHODS
  Induced-sputum samples were collected from 24 COPD patients with median age of 52 years (interquartile range [IQR], 44 to 58 years) and FEV(1) percentage of predicted of 78.05% (IQR, 75.8 to 80.1%) at the onset of mild exacerbations not requiring hospitalization and when stable. Inflammatory cells and T-lymphocyte subpopulations (CD4+, CD8+, and cells producing interferon [IFN]-gamma or interleukin [IL]-4) were measured using flow cytometry and immunocytochemical methods.
  
  
  RESULTS
  A significant increase in sputum CD8+ T lymphocytes (p < 0.0001) and significant decreases in CD4+ T lymphocytes as well as in CD4+/CD8+ (p = 0.0001) and CD8+IFN-gamma+/CD8+IL-4+ (p = 0.001), CD4+IFN-gamma+/CD4+IL-4+ (p = 0.0003) sputum cells ratios were found decreased at the onset of exacerbations compared to stable condition. The changes in T-lymphocyte subpopulations were not associated with smoking history, demographic characteristics, or disease severity.
  
  
  CONCLUSIONS
  The findings of the present study suggest that CD8+ lymphocytes are increased and potentially polarized toward a Tc2 profile in the airways of COPD patients at the onset of COPD exacerbations with respect to stable condition. The clinical impact of the observed phenomenon requires further investigation.
authors.affiliation: Department of Thoracic Medicine, University Hospital, Medical School, University of Larisa, Larisa. Electronic address: appollon7@hotmail.com.
authors.forename: Demosthenes
authors.initials: D
authors.lastname: Makris
authors.affiliation: Department of Thoracic Medicine, University Hospital, Medical School, University of Larisa, Larisa.
authors.forename: Stelios
authors.initials: S
authors.lastname: Lazarou
authors.affiliation: Department of Hematology, Medical School, University of Crete, Heraklion, Greece.
authors.forename: Michael
authors.initials: M
authors.lastname: Alexandrakis
authors.affiliation: Department of Hematology, Medical School, University of Crete, Heraklion, Greece.
authors.forename: Taxiarchis V
authors.initials: TV
authors.lastname: Kourelis
authors.affiliation: Department of Epidemiology, Medical School, University of Crete, Heraklion, Greece.
authors.forename: Nikos
authors.initials: N
authors.lastname: Tzanakis
authors.affiliation: Department of Hematology, University Hospital, Medical School, University of Larisa, Larisa.
authors.forename: Despina
authors.initials: D
authors.lastname: Kyriakou
authors.affiliation: Department of Thoracic Medicine, University Hospital, Medical School, University of Larisa, Larisa.
authors.forename: Kostas I
authors.initials: KI
authors.lastname: Gourgoulianis
mesh_terms: D000328:Adult; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology / Q000502:physiology*; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology / Q000502:physiology*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D016131:Lymphocyte Subsets / Q000473:pathology / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology*; D013183:Sputum / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000473:pathology / Q000502:physiology*
chemical_list: D015847:Interleukin-4; D007371:Interferon-gamma