BackgroundCC10 is an endogenous anti-inflammatory product supposed to protect against lung injury since decreased levels were reported in many respiratory diseases. Its exact rôle in the development of chronic airflow impairment in smokers remains to be determined.Our study investigated CC10 levels in induced sputum in smokers who developed or not a fixed chronic airflow impairment and to elucidate its potential relationships with other pro-and anti-inflammatory indices.MethodsInduced sputum of 22 smokers (13 stage GOLD 2 and 9 stage GOLD 0, matched for âge, sex and smoking) were collected for cellularity, CC10, TIMP1 and MMP9 levels.ResultCC10 and TIMP1 were decreased in COPD when compared to asymptomatic smokers. CC10 levels positively correlated with macrophages (r = 0.55, p.02), TIMP-1 (r = 0.66, p.01), and MMP9/TIMP1 molar ratio (r = -0.49, p.002).ConclusionSpécifie Clara cells damage reflected by low sputum CC10 levels can be evoked as an important mechanism in smokers who developed chronic airflow impairment.