AGER and inflammatory response: This finding accords with the knowledge that COPD is characterized by chronic inflammation in the lung and airways 28, 29; immune response mediates the development of COPD caused by the harmful stimuli 30, 31, 32; lipopolysaccharide may lead to increased airway and systemic inflammation, and contribute to the progressive deterioration of lung function 33, 34; and RAGE is a ‘driving force’ for cigarette smoke (CS)‐induced airway inflammation in COPD 35.