Nanoparticles in induced sputum - a window to airway inflammation among active smokers.

To evaluate the role of nanoparticles (NP) in sputum samples of active smokers as markers of inflammation and disease. 29 active smokers were included (14 with chronic obstructive pulmonary disease [COPD]) and underwent clinical assessment, pulmonary function tests, sputum induction (with NP analysis) and blood sampling. Higher particle and NP concentrations and smaller mean size directly correlated with clinical parameters such as the COPD Assessment Test score and impulse oscillometry results. Similar correlations were found between NPs and increased sputum IL-1β, IL-6 and TNF-α. Among COPD patients, higher IL-8 and lower IL-10 serum levels also correlated with NP concentrations. This proof-of-concept study shows the potential of sputum NPs as markers of airway inflammation and disease.