With respect to the possible mechanisms involved in the regulation of DEFB1 in the airways of patients with COPD, the methylation analysis of CpG sites within the DEFB1 promoter and coding sequence showed no remarkable differences in the methylation pattern when bronchial epithelial cell biopsies obtained from patients with COPD were compared with biopsies from healthy controls. This evidence concerns the gene DEFB1 and chronic obstructive pulmonary disease.