Dynamics of mast cell degranulation in human allergic nasal epithelium after provocation with allergen.

The histamine content in the nasal epithelial layer of twenty-five patients with nasal allergy was measured before, 10 min after and 1 hr after nasal provocation with allergen. A decrease in histamine content was observed 10 min after provocation compared to the values obtained before provocation (P less than 0.05). There was a tendency for an increase in the histamine content of the nasal epithelium one hour after provocation when compared with the amounts present 10 min after provocation (P less than 0.1). Mast cells in the nasal epithelial layer of a further five patients were studied by electron microscopy 10 min and 1 hr after provocation. The rate of mast cell degranulation appeared to decrease 1 hr after provocation when compared with 10 min. Our study suggests that some mast cells commence their migration to the nasal epithelial layer over a short time period and that they may play a role in the onset of the allergic nasal reaction in patients with allergic nasal symptoms.