Nasal inflammatory mediators and specific IgE production after nasal challenge with grass pollen in local allergic rhinitis

Background

Evidence exists of a new form of local allergic rhinitis (LAR) with local production of specific IgE (sIgE) and a positive response to nasal allergen provocation test (NAPT) in patients previously diagnosed with idiopathic rhinitis. However, the immunologic mechanisms involved are still poorly understood.

Objective

We explored the involvement of nasal sIgE, eosinophil, and mast cell activation in the response to NAPT with grass pollen (NAPT-grass) in a group of patients already classified with LAR.

Methods

Out-of-spring NAPT-grass was performed in 30 patients with LAR and 30 healthy controls. Nasal symptoms, acoustic rhinometry, and nasal lavage were performed at baseline and 15 minutes and 1, 6, and 24 hours post-NAPT. Tryptase, eosinophilic cationic protein (ECP), and total and sIgE to grass pollen were measured in nasal lavage by immunoassays.

Results

NAPT-grass was positive in all patients with LAR. We detected significant increases of tryptase and ECP in 40% and 43%, respectively, at 15 minutes and 1, 6, and 24 hours post-NAPT compared with baseline (P < .05). sIgE was increased in 30%, with significant increases at 1 and 6 hours (P < .05) and 24 hours (P = .002) post-NAPT. The maximum release of tryptase was detected 15 minutes after NAPT, whereas the maximum release of ECP and sIgE was detected 24 hours after challenge. NAPT-grass was negative in all healthy controls, with no increase in tryptase, ECP, total IgE, or sIgE.

Conclusion

These results demonstrate that patients with LAR had local production of sIgE and mast cell/eosinophil activation induced by nasal exposure to grass pollen.

Key words: ECP, grass, local allergic rhinitis, nasal allergen provocation test, nasal lavage, nasal specific IgE, tryptase

Abbreviations used: ECP, Eosinophilic cationic protein, IR, Idiopathic rhinitis, LAR, Local allergic rhinitis, NAPT, Nasal allergen provocation test, NAPT-grass, Nasal allergen provocation test with grass pollen, sIgE, Specific IgE, VAS, Visual analog scale, VOL 2-6cm, Volume of the nasal cavity from 2 to 6cm