This is consistent with the findings by Willemse et al. that in asymptomatic smokers who successfully quitted, inflammation in the lung (number of sputum macrophages, percentage of eosinophils and IL-8 levels) was significantly reduced; although, those already developed COPD had steady inflammatory profile after quitting smoking [40]. This evidence concerns the gene CXCL8 and chronic obstructive pulmonary disease.