Chronic bronchitis sub-phenotype within COPD: inflammation in sputum and biopsies

Abstract

The presence of chronic bronchitis predicts a more rapid decline of forced expiratory volume in one second (FEV1) in patients with chronic obstructive pulmonary disease (COPD). The hallmark of COPD is airway inflammation. It was hypothesised that COPD patients with chronic bronchitis are characterised by a distinct inflammatory cell profile, as measured in bronchial biopsies and sputum.From 114 COPD patients (male/female ratio 99/15, mean¡SD age 62¡8 yrs, current smoking 63%, post-bronchodilator FEV1 63¡9% predicted, no steroids), with and without chronic bronchitis, inflammatory cell counts in bronchial biopsies and induced sputum were measured. Analysis was carried out by logistic regression.COPD patients with chronic bronchitis had lower eosinophil counts in biopsies and higher percentages of sputum eosinophils than patients without those symptoms, which remained after adjustment for smoking and sex. Patients with chronic bronchitis also showed higher percentages of macrophages and lower percentages of neutrophils in sputum, which could be explained by differences in smoking and sex.It was concluded that chronic bronchitis reflects an inflammatory sub-phenotype among patients with chronic obstructive pulmonary disease. The present results indicate a preferential distribution of eosinophils towards the airway lumen in patients with chronic bronchitis. This may have implications for anti-inflammatory treatment of chronic obstructive pulmonary disease patients with chronic bronchitis.

Imaging Pulmonary Inflammation

“…Preliminary results from our own institution, from a protocol approved by our Institutional Review Board and with written consent from participants, further suggest that patients with chronic bronchitis symptomatology have increased 18 F-FDG uptake compared with those without such symptoms ( Fig. 2; data published in abstract form from Chen et al (52)), in line with the known increased lung inflammation that occurs with chronic bronchitis (55). Together, the available data suggest that 18 F-FDG uptake may be useful in distinguishing inflammatory phenotypes within COPD.…”

The Importance of Chronic Bronchitis in Chronic Obstructive Pulmonary Disease

“…Although neutrophils are clearly associated with chronic bronchitis, it is likely that many immune cell populations are involved in the pathogenesis of this disease. Interestingly, there are few differences in the cellular content of bronchial biopsies taken from patients with COPD with and without chronic bronchitis (122) although one study has suggested a predominance of eosinophils in airway secretions when chronic bronchitis is present (123), however this observation has not been replicated. The numbers of CD8+ lymphocytes in bronchial tissue relate inversely with FEV 1 (122) and have been shown capable of causing lung tissue damage both by their own cytotoxicity and by recruiting macrophages by secreting IFN-.…”

Macrophages are related to goblet cell hyperplasia and induce MUC5B but not MUC5AC in human bronchus epithelial cells

“…50 Among COPD patients, a group present chronic bronchitis, and COPD groups with or without chronic bronchitis have similar high amounts of macrophages in bronchial biopsies. 51 Therefore, we believe that any COPD group with high TNF-a levels in bronchial macrophages could benefit from an anti-TNF-a intervention to inhibit MUC5B þ GCH. However, our hypothesis needs to be validated using HBEC from patients, as bronchus cells from a healthy donor can be genetically and functionally different to diseased airway epithelial cells.…”