The study will include 60 healthy subjects (ex-smoker without any airflow limitation), 125 COPD GOLD (global initiative for chronic obstructive lung disease) I , 125 COPD GOLD II, 125 COPD GOLD III and up to 20 patients with COPD and A1AT (Alpha1-Antitrypsin) deficiency (ZZ genotype). Soluble and imaging biomarkers will be investigated addressing different aspects of disease pathways postulated to be relevant for COPD progression.