[Analysis of airway inflammation in asthma: clinical academic interest]

While the importance of airway inflammation in severe asthma was known from the pathologists for more than one century, the demonstration of an airway inflammatory process in mild asthma dates back to the early nineties. With the advent of bronchoscopy making it possible to sample biopsies and bronchoalveolar lavage, it has become clear that mild to moderate asthma was characterized by a Th2 driven airway eosinophilic inflammation where cytokine like IL-4, IL-5 and IL-13 play a critical role. Soon after, were developed the technique of induced sputum and the measurement of exhaled nitric oxide as non invasive tools to assess airway inflammation. The application of these techniques on large samples of subjects has been instrumental to the development of the concept of inflammatory phenotype in asthma which proved to be pertinent in the drug management of the disease. Therefore, within a 20 year laps, the monitoring of airway inflammation, also called inflammometry, has gone beyond the academic world to become crucial for the appropriate management of asthmatics by the clinician.