The effects of cromolyn sodium on the nasal mast cells.

To elucidate the characteristics of two different kinds of nasal mast cells, ie, the mucosal mast cells (MMC) and connective tissue mast cells, we examined the inhibitory effects of cromolyn sodium (CS) on in vitro allergen-induced histamine release from the nasal mast cells. The pharyngeal mast cells were also examined as control. Nasal scrapings (containing mainly MMC) were faintly sensitive to CS, whereas both the chopped nasal mucosas without epithelial layer and chopped pharyngeal mucosas (containing mostly connective tissue mast cells) were markedly sensitive in patients with allergic rhinitis. This result indicates that there are at least two distinct types of mast cells in allergic nasal mucosa, and the nasal MMC are insensitive to CS.