Inflammatory cells and remodeling in bronchial biopsies from COPD patients and controls

The understanding of inflammation and remodeling in the bronchial wall of
COPD patients with varying disease severity remains incomplete. 35 healthy
controls and 47 volunteer COPD patients underwent bronchoscopy with
bronchoalveolar lavage (BAL) and sampling by endobronchial biopsies in
2014-2015 as part of the MicroCOPD Study. Biopsies were embedded in glycol
methyl acrylate (GMA) resin and examined by immunohistochemistry and
staining for enumeration of CD3+, CD4+, CD8+, CD20+, CD68+, EG2+, and NE+
inflammatory cells, as well as endothelial cells (EN4) and smooth muscle
actin (SMA). Mucus cells were stained by periodic acid-schiff (PAS) and
toluidine blue to visualize the reticular basement membrane (RBM). The
number of macrophages and eosinophils was higher, and vascularity
increased in the submucosa in COPD patients compared with healthy
controls. In healthy smokers, there were lower numbers of lymphocytes
(CD3+, CD4+, CD8+, CD20+) than in never smokers. However, COPD patients
with GOLD I/II had higher numbers of eosinophils and larger smooth muscle
area compared with GOLD III/IV. COPD exacerbations the last year, blood
eosinophils, and use of inhaled corticosteroids did not affect levels of
inflammation or remodeling. Smoking alters inflammation in healthy
controls, while specific patterns of macrophages, eosinophils, and
vascularity distinguish COPD from non-COPD in bronchial biopsies.