Late-phase asthmatic responses and airway inflammation

Recent studies suggest that the functional abnormalities in asthma (i.e., airway obstruction and hyperresponsiveness) can be the consequence of airway inflammation caused by inhaled allergens or chemical sensitizers or by viral infections. Although bronchodilators have some beneficial effect on the late asthmatic response, their value is limited when this is more severe, and they have no effect on the associated prolonged increase in responsiveness or the cellular phase of airway inflammation. In contrast, corticosteroids effectively inhibit both the inflammatory asthmatic response and heightened airway responsiveness. Serial measurements of airway responsiveness relative to exposure to allergens or chemical sensitizers and treatment indicate that airway inflammation cannot only be the primary cause of asthma but can also be responsible for its persistence and for exacerbations. Therefore anti-inflammatory drugs should be considered first-line treatment to minimize both airway obstruction and hyperresponsiveness and the need for bronchodilators.