Figure 1

The percentage of induced sputum (IS) neutrophils in the smoking cessation group (n = 17, see Table 2) at the onset of smoking cessation (baseline) and at 3 and 6 months after stopping smoking. IS neutrophils were significantly higher in the smoking cessation group at the baseline compared to the non-smokers (p = 0.021). Neutrophils increased significantly from baseline at 3 months after cessation (p = 0.035) and declined to the levels of non-smokers at 6 months after the cessation.