Distribution of T-cell subsets in BAL fluid of patients with mild to moderate COPD depends on current smoking status and not airway obstruction

Chest. 2014 Apr;145(4):711-722. doi: 10.1378/chest.13-0873.


Background: COPD is characterized by chronic inflammation. CD8+ T cells and CD4+ T cells have both been implicated in the inflammatory response. We investigated whether the lymphocyte and T-cell subpopulations in BAL differ between patients with COPD who are current smokers and those who are ex-smokers.

Methods: Forty never smokers, 40 smokers with normal lung function, and 38 patients with COPD, GOLD (Global Initiative for Chronic Obstructive Pulmonary Disease) stage I-II (27 smokers and 11 ex-smokers) underwent BAL. Using flow cytometry, cells were analyzed from BAL and blood for T-cell subsets, B cells, natural killer cells, and natural killer T (NKT)-like cells. The differentiation status of CD4+ T cells was also determined.

Results: Smokers with or without COPD had higher percentages of CD8+ T cells and NKT-like cells in BAL than did never smokers and ex-smokers with COPD. Most of the NKT-like cells were CD8+. In contrast, the percentages of CD4+ T cells were lower in the smoking than in the nonsmoking groups. In blood, the frequency of CD4+ T cells was increased in the two smoking groups. Current smokers also had increased numbers of activated (CD69+) naive and effector CD4+ T cells in BAL compared with nonsmokers, particularly in patients with COPD. In male smokers with COPD, the percentage of CD8+ T cells in BAL positively correlated with the number of cigarettes per day.

Conclusions: Current smoking status has a greater impact than airway obstruction on the distribution of T-cell subsets in BAL of patients with mild to moderate COPD. This fact must be considered when the role of T cells in COPD is evaluated. Our results stress the importance of subgrouping patients with COPD in terms of smoking.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Airway Obstruction / blood*
  • Airway Obstruction / complications
  • Bronchoalveolar Lavage Fluid / cytology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pulmonary Disease, Chronic Obstructive / blood*
  • Pulmonary Disease, Chronic Obstructive / complications
  • Severity of Illness Index
  • Smoking / blood*
  • T-Lymphocyte Subsets*