The clinical relevance of airway inflammation.

: Inflammation forms an integral part of the normal defence mechanisms of the airways. Airway inflammation is therefore in essence beneficial, although prolonged exposure to noxious stimuli, overwhelming damage or insufficient control of the inflammatory process may lead to clinical disease. However, the factors contributing to the type and magnitude of airway inflammation, including the level at which damage occurs, the individual difference in sensitivity and inflammatory response to noxious stimuli and the evolution from acute to chronic inflammation, are insufficiently characterized. Clinical, pathological and experimental investigations clearly show that airway inflammatory disorders are heterogeneous. Mucus hypersecretion and bronchial hyperresponsiveness are different characteristics of airway diseases with distinct clinical manifestations and prognostic significance. Epidemiological studies have shown that bronchial hyperresponsiveness is associated with a worse prognosis in obstructive airway disease. Further efforts are needed to understand the impact of different parts of the airway inflammatory process on the physiological and clinical manifestations of airway diseases. Understanding the mode of action of existing and newly developed therapeutic agents on airway inflammation will teach us more about its role in these frequent disorders.