Background Although nasal challenge with allergen has often been used to evaluate the efficacy of therapeutic modalities used for the treatment of allergic rhinitis, the reproducibility of this model in quantitatively evaluating efficacy has not been rigorously examined.
Objective To examine the reproducibility of the suppressive effects of an intranasal corticosteroid on the clinical and biochemical outcomes of a nasal allergen challenge during two identical treatment periods using the same subjects.
Methods In a single-blind study, 25 seasonal allergic subjects with positive skin tests to grass or ragweed were studied outside of their pollen season. Subjects underwent a baseline, three-dose allergen challenge. Beginning 1 week later, subjects received two 7-day courses of intranasal beclomethasone (168 μg b.i.d.) separated by a 1-month washout period. Nasal challenges with allergen were performed after each treatment period. The nasal allergic response was evaluated by counting sneezes, recording symptom scores and measuring levels of albumin (an index of vascular permeability), lysozyme (an index of serous glandular secretion) and kinins (proinflammatory peptides) in recovered nasal lavages.
Results Compared with the baseline challenge, each course of beclomethasone significantly reduced sneezing, symptom scores, albumin and kinins, but not lysozyme. Reproducibility analysis of the net changes from diluent challenge in the two beclomethasone treatment periods, showed the following intraclass correlation coefficients: sneezing (0.92), lysozyme (0.82), symptom scores (0.72), albumin (0.64) and kinins (0.28).
Conclusion We conclude that the nasal challenge model is a reproducible method to evaluate the efficacy of anti-allergic medications. For nasal corticosteroid trials, sneezing, symptom scores and albumin levels are recommended as the most reproducibly suppressive outcome measures.
Cite this as: D. Proud, D. K. Riker and A. Togias, Clinical & Experimental Allergy, 2010 (40) 738–744.