Inflammation

It is now well established that inflammation is of critical importance in asthma and this has been a major impetus to changing the management of asthma, with emphasis on the early use of anti-inflammatory treatments. Inflammation is also important in COPD; chronic inflammation is present in the airways and lung parenchyma of patients with COPD, although the pathophysiologic significance of this inflammation is currently uncertain. The inflammatory process in COPD differs in most respects from that in asthma in terms of inflammatory cells, inflammatory mediators, inflammatory responses and response to corticosteroid therapy.1 However, some patients with COPD (10%) also have asthma and therefore may share inflammatory features. Cigarette smoking itself induces an inflammatory response and the inflammatory changes described in COPD appear to be an exaggeration of the normal inflammatory response to an irritant.2 More comparisons between COPD patients and individuals with normal lung function who are matched for smoking exposure are needed. It is also important to differentiate COPD from asthma, and a negative trial of corticosteroids is recommended in selecting suitable patients for study. There is little information about the inflammatory process in patients with COPD that is not due to smoking.3