Mediator release of neuropeptides after nasal provocation in perennial allergic rhinitis patients

Abstract

Neuropeptides may play a role in allergic rhinitis including development of vasodilation and vascular leakage, which may result in rhinorrhea and congestion. While neuropeptide release during the immediate allergic response is well known, the role of neuropeptides in the late phase of allergic responses is less well defined. Eleven subjects with dust mite allergy induced allergic rhinitis were compared to 5 healthy control subjects using nasal allergen provocation. Nasal lavage fluid was analyzed for Substance P, bradykinin, and total protein. RESULTS Both bradykinin and substance P levels increased in nasal lavage fluid immediately after dust mite allergen challenge of dust mite allergic subjects, the magnitude of increase of both neuropeptides being significantly correlated. There was a greater increase in substance P versus bradykinin 4 to 6 hours after allergen challenge, with a lack of correlation between the late phase increases of these two neuropeptides. The bradykinin increases correlated with the increase in total protein in the nasal lavages of the allergic subjects, whereas the increases in substance P did not correlate with the total protein in the nasal lavages. An increase in nasal eosinophils was only seen in the allergic subjects after allergen provocation. Both bradykinin and substance P appear in nasal lavage fluid 4 to 6 hours after allergen challenge of dust mite allergic subjects, suggesting a role for the neuropeptides in late phase allergic events.