title: Expansion of CD4+CD25+ helper T cells without regulatory function in smoking and COPD.
abstract: BACKGROUND
  Regulatory T cells have been implicated in the pathogenesis of COPD by the increased expression of CD25 on helper T cells along with enhanced intracellular expression of FoxP3 and low/absent CD127 expression on the cell surface.
  
  
  METHODS
  Regulatory T cells were investigated in BALF from nine COPD subjects and compared to fourteen smokers with normal lung function and nine never-smokers.
  
  
  RESULTS
  In smokers with normal lung function, the expression of CD25+CD4+ was increased, whereas the proportions of FoxP3+ and CD127+ were unchanged compared to never-smokers. Among CD4+ cells expressing high levels of CD25, the proportion of FoxP3+ cells was decreased and the percentage of CD127+ was increased in smokers with normal lung function. CD4+CD25+ cells with low/absent CD127 expression were increased in smokers with normal lung function, but not in COPD, when compared to never smokers.
  
  
  CONCLUSIONS
  The reduction of FoxP3 expression in BALF from smokers with normal lung function indicates that the increase in CD25 expression is not associated with the expansion of regulatory T cells. Instead, the high CD127 and low FoxP3 expressions implicate a predominantly non-regulatory CD25+ helper T-cell population in smokers and stable COPD. Therefore, we suggest a smoking-induced expansion of predominantly activated airway helper T cells that seem to persist after COPD development.
authors.affiliation: Dept. of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Sweden. ester.roos-engstrand@lung.umu.se
authors.forename: Ester
authors.initials: E
authors.lastname: Roos-Engstrand
authors.forename: Jamshid
authors.initials: J
authors.lastname: Pourazar
authors.forename: Annelie F
authors.initials: AF
authors.lastname: Behndig
authors.forename: Anders
authors.initials: A
authors.lastname: Bucht
authors.forename: Anders
authors.initials: A
authors.lastname: Blomberg
mesh_terms: D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D016022:Case-Control Studies; D049109:Cell Proliferation; D005260:Female; D005434:Flow Cytometry; D005541:Forced Expiratory Volume; D051858:Forkhead Transcription Factors / Q000032:analysis; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis*; D053699:Interleukin-7 Receptor alpha Subunit / Q000032:analysis; D008168:Lung / Q000503:physiopathology; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000276:immunology* / Q000503:physiopathology; D012907:Smoking / Q000009:adverse effects / Q000276:immunology*; D013147:Spirometry; D013548:Sweden; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D014797:Vital Capacity
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit; D053699:Interleukin-7 Receptor alpha Subunit