An Investigation Into the Mechanisms of Action of a Combined Long Acting Beta Agonist/Inhaled Corticosteroid (Seretide 500 Accuhaler) on the Bacterial Colonisation, Immunology and Inflammation of Patients With Chronic Obstructive Pulmonary Disease

We aim to recruit equal numbers of healthy smokers, mild, moderate and severe COPD patients (12 patients to be recruited from each group). These patients will never have been prescribed the components present in Seretide (Salmeterol and Flixotide or similar compounds).

The patients will have spirometry at the beginning of the study to confirm the presence of COPD. Healthy smokers will defined as ex or current smokers who match the study population but have normal lung function.

Patients with a history of asthma, bronchiectasis, carcinoma of the bronchus, or other significant respiratory disease will be excluded.

The patients will have a total of four study visits, 2 off treatment and 2 while on treatment, over a 56 day study period. At each study visit induced sputum will be performed and blood extracted. The cells fom both of these samples will be analysed for cells type and activation. Sputum and serum will be stored for cytokine analysis at a later date.

The Sputum will be induced using standardised protocols using nebulised saline solution.