The role of mast cells in asthma.

Mast cells store or generate a number of substances, such as histamine, leukotrienes, specific chemotactic factors, and proteases, which have potent inflammatory effects. Mast cells are present in mammalian lung in the bronchial wall, in the epithelium itself, and in airway lumens. Evidence implicating mast cells in the induction of airway muscle constriction and mucosal inflammation includes direct studies of mast cell secretion, measurement of histamine release, and inhibition of asthmatic reactions with antihistamines and with the inhibitor of mast cell degranulation, sodium cromoglycate. Definitive evaluation of the role of the mast cell in asthma remains elusive, in part because of the general hyperactivity of airway smooth muscle in asthmatics.