Modification of Chronic Inflammation by Inhaled Carbon Monoxide in Patients With Stable Chronic Obstructive Pulmonary Disease (COPD)

Inclusion Criteria: Men and women, age > 40 years. Women must be post-menopausal (i.e. at least one year must have passed after the last menstruation), surgically sterile or using acceptable contraceptives, as judged by the investigator. A diagnosis of COPD according to the criteria of the American Thoracic Society (ATS); a disease state characterised by the presence of chronic airway obstruction due to chronic bronchitis (cough/sputum on most days a week for 3 months a year for at least two successive years); or emphysema. FEV1 > 0.7 litres FEV1/FVC ratio < 70% (equation retrieval system [ERS] equations) A smoking history of > 10 pack years Completely stopped smoking > 1 year ago No upper or lower respiratory tract infection in the last 4 weeks In a stable phase of COPD, as judged by the investigator Signed and dated informed consent obtained before any study related procedures (including withdrawal of concomitant medication) are conducted Exclusion Criteria: Treatment with immune-modulating agents for any other disease History of asthma; former diagnosis of asthma Arterial oxygen tension (PaO2) < 8.0 kPa Any significant other pulmonary disease or disorder (e.g. alpha1-antitrypsin deficiency, bronchiectasies), as judged by the investigator Patients with other significant disease or disorder (like cardiovascular, gastrointestinal, liver, renal, neurological, musculoskeletal, endocrine, metabolic [including diagnosed diabetes], malignant, psychiatric, major physical impairment), which, in the opinion of the investigator may either put the patient at risk because of participation in the study; or may influence the results of the study, or the patient's ability to participate in the study. Patients unable to blow reproducable lung function measurements Patients using medicine with anti-oxidant character like n-acetyl-cysteine.