The role of basophils in asthma. I. Sodium cromoglycate on histamine release and content.

The increased plasma-histamine levels observed after provocation of asthmatic subjects with antigen or exercise may result from the release of this granule-associated mediator from either mast cells or basophil leucocytes. In this preliminary study, designed to ilucidate the source and role of mediators in asthma, the effects of sodium cromoglycate on basophil-histamine release has been assessed. Basophil histamine-release in vitro was not inhibited by 0.01-100 microgram/ml sodium cromoglycate. When administered by inhalation at a dose of 20 mg every 8 hr to six subjects, the drug did not modify the ability of basophils to synthesize and store histamine or to release histamine on incubation with antigen. As sodium cromoglycate reduces IgE-dependent histamine release from human mast-cells, these results suggest that lung mast-cells, rather than circulating basophils, are source of mediators in exacerbations of asthma and following exercise or antigen bronchial-provocation in asthmatic subjects.