Abstract
Background: The pivotal role of neutrophils and macrophages in smoking-related lung inflammation and COPD development is well-established.
Objectives: We aimed to assess whether sputum concentrations of Human Neutrophil Peptides (HNP), Neutrophil Elastase (HNE), Interleukin-8 (IL-8), and Metalloproteinase-9 (MMP-9), major products of macrophages and neutrophils, could be used to trace airway inflammation and progression towards pulmonary functional impairment.
Methods: Forty-two symptomatic smokers and 42 COPD patients underwent pulmonary function tests; sputum samples were collected at the enrolment, and 6 months after smoking cessation.
Results: HNP, HNE, IL-8, MMP-9 levels were increased in individuals with COPD (p<0.0001). HNP and HNE concentrations were higher in patients with severe airways obstruction, as compared to patients with mild-to-moderate COPD (p=0.002). A negative correlation was observed between FEV1 and HNP, HNE and IL-8 levels (p<0.01), between FEV1/FVC and HNP, HNE and IL-8 levels (p<0.01), and between HNE levels and FEV1 rate of decline after 2 years (p=0.04).
ROC analysis, to discriminate symptomatic smokers and COPD patients, showed the following AUCs: for HNP 0.92; for HNE 0.81; for IL-8 0.89; for MMP-9 0.81; for the four variables together 0.981.
Conclusions: The data suggest that the measurement of sputum markers may have an important role in clinical practice for monitoring COPD.
Further investigations are needed to validate the potential ability of sputum biomarkers to monitor the disease in patients with COPD, and to predict which subgroup of smoking subjects could be at risk to develop functional impairment.
- © 2011 ERS
