Role of inflammatory mediators in asthma.

Release of inflammatory mediators such as histamine and products of arachidonic acid metabolism has been demonstrated in bronchoalveolar lavage fluid of patients with asthma. Their precise cellular source is not clear but many cells types such as eosinophils, macrophages and mast cells may contribute to the generation of a wide variety of chemical mediators. These can mimic many of the features associated with asthma including bronchoconstriction, bronchial hyperresponsiveness and airway microvascular leakage. Development of specific mediator receptor antagonists or inhibitors of mediator synthesis may clarify the role of particular inflammatory mediators such as the sulphidopeptide leukotrienes or platelet-activating factor in asthma. It seems unlikely that only one particular mediator is responsible for all the manifestations of asthma.