New paradigms in the pathogenesis of chronic obstructive pulmonary disease II.

A vicious circle of infection and inflammation in the airways in chronic obstructive pulmonary disease (COPD) could cause progressive lung damage and contribute to progressive loss of lung function characteristic of this disease. Bacteria and viruses cause a substantial proportion of exacerbations of COPD, which have now been clearly characterized as inflammatory events with adverse consequences in the course of COPD. Chronic infection by virus, bacteria, and other microbes is also prevalent in COPD, and human and experimental data are linking this chronic infection to COPD pathogenesis. COPD is heterogeneous; therefore it is likely infections have a varying degree of importance among patients with this disease.