Background: Chronic obstructive pulmonary disease (COPD) is associated with airway inflammation. Although smoking cessation improves symptoms and the decline in lung function in COPD, it is unknown whether bronchial inflammation in patients with established COPD varies with the duration of smoking cessation.
Methods: 114 patients (99 men) with COPD of mean (SD) age 62 (8) years, a median (IQR) smoking history of 42 (31–55) pack years, no inhaled or oral corticosteroids, all current or ex-smokers (n = 42, quit >1 month, median cessation duration 3.5 years), post-bronchodilator FEV1 63 (9)% predicted, and FEV1/IVC 48 (9)% were studied cross sectionally. The numbers of subepithelial T lymphocytes (CD3, CD4, CD8), neutrophils, macrophages, eosinophils, mast cells, and plasma cells were measured in bronchial biopsy specimens (median (IQR)/0.1 mm2) using fully automated image analysis.
Results: Ex-smokers with COPD had higher CD3+, CD4+, and plasma cell numbers than current smokers with COPD (149 (88–225) v 108 (61–164), p = 0.036; 58 (32–90) v 40 (25–66), p = 0.023; and 9.0 (5.5–20) v 7.5 (3.1–14), p = 0.044, respectively), but no difference in other inflammatory cells. Short term ex-smokers (<3.5 years) had higher CD4+ and CD8+ cell numbers than current smokers (p = 0.017, p = 0.023; respectively). Conversely, long term ex-smokers (quit ⩾3.5 years) had lower CD8+ cell numbers than short term ex-smokers (p = 0.009), lower CD8/CD3 ratios than both current smokers and short-term ex-smokers (p = 0.012, p = 0.003; respectively), and higher plasma cell numbers than current smokers (p = 0.003).
Conclusions: With longer duration of smoking cessation, CD8 cell numbers decrease and plasma cell numbers increase. This indicates that bronchial T lymphocyte and plasma cell counts, but not other inflammatory cells, are related to duration of smoking cessation in patients with COPD.
- plasma cells
- T lymphocytes
- chronic obstructive pulmonary disease
- smoking cessation
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↵* The GLUCOLD Study Group: Groningen Leiden Universities and Corticosteroids in Obstructive Lung Disease; a full list of members is given in the Appendix to this paper.
Published Online First 2 September 2005
The study was supported by the Netherlands Organization for Scientific Research (NWO), the Netherlands Asthma Foundation (NAF), GlaxoSmithKline (NL), Leiden University Medical Center (LUMC), and Groningen University Medical Center (GUMC).
PS and PH have received, as members of the Department of Pulmonology of the Leiden University Medical Centre, a grant from GSK (UK and NL) as part of the sponsorship of this GLUCOLD study. The other authors declare no competing interests.