Changes in Contents of Arachidonic Acid Metabolites in Nasal Lavage and Mucosal Tissues in response to Allergen Challenge in Patients with Allergic Rhinitis

Background: Allergic rhinitis is recognized as being not purely a histamine-related disease. Three arachidonate metabolites, i.e. leukotriene (LT), thromboxane (TX) A2 and prostaglandin (PG) D2, have gathered more interest because of increasing evidence supporting a causal relationship for these mediators. We attempted to evaluate changes in the contents of these three mediators not only in nasal lavage but also in mucosal tissue.

Methods: The contents of three arachidonic acid metabolites; PGD2, TXB2, LT C4, D4 and E4 (LTs), in nasal lavage and nasal mucosal tissues in subjects with allergic rhinitis after antigen challenge were measured.

Results: The highest level of these three mediators in nasal lavage was achieved at 15 min after challenge. In most subjects that showed the late NAR response, an apparent second mediator rise was observed. While the secondary rise of PGD2 and TXB2 was seen from 4 to 8 hr. after the challenge at which the NAR response was seen, that of LTs was seen 2 to 4 hr. after the challenge and preceded the late NAR response by about 2 hrs.

In the non-allergic subjects, the contents of PGD2, TXB2, and LTs were not significantly altered by the exposure to HD allergen. In the challenged side of the allergic subjects, the contents of all the three mediators were significantly high.

Conclusion: The relative content of the three arachidonic acid metabolites in the mucosa after provocation was found to be different from that observed in the lavage fluid; the amount found in the lavage does not reflect the relative amount formed in the mucosa.