Mucosal inflammation in idiopathic bronchiectasis: cellular and molecular mechanisms

Bronchiectasis is a chronic and debilitating lung disease, characterised by irreversible dilatation of the bronchi as consequence of airway injury and remodelling due to recurrent or chronic airway inflammation and infection. The underlying aetiologies include autoimmune diseases, severe infections, genetic abnormalities and acquired disorders. The pathogenesis of bronchiectasis is poorly understood. Three distinct pathogenetic elements, namely infection, inflammation and enzymatic actions, which interact with each other, have been implicated in the pathophysiology of bronchiectasis. Some recent observations indicate that airway inflammation in bronchiectasis comes from a deregulated cytokine network independent of bacterial airway colonisation. In the present review, current knowledge about cellular and molecular inflammatory events in the dynamic process of host–pathogen interaction that are thought to play a relevant role in the pathogenic mechanisms of airway wall destruction leading to bronchiectasis are discussed.