Source:Annals of Allergy, Asthma & Immunology
Author(s): Mena Soliman, Lisa M. Steacy, Jenny Thiele, Dan E. Adams, Helen L. Neighbour, Anne K. Ellis
BackgroundNasal Allergen Challenge(NAC) models have been used to study allergic rhinitis and new therapies. Symptoms and biological samples can be evaluated at time points following allergen exposure.ObjectiveVerification of protocol repeatability and adequate interval between allergen exposures.Methods10 ragweed allergic participants were exposed to incrementally increasing dosages of ragweed allergen intra-nasally until they achieved a Total Nasal Symptom Score(TNSS) of 8/12 and a Peak Nasal Inspiratory Flow(PNIF) >=50% reduction from baseline. 3 weeks later participants were challenged with a cumulative dose equal to the sum of all the allergen doses received at screening. TNSS and PNIF were recorded at regular intervals including a 24h assessment. A repeat visit was conducted after a further 3 weeks. Nasal secretion samples were collected for cytokine and eosinophil quantification.Results9 participants completed all visits. TNSS and PNIF responses followed previous patterns, with an initial peak at 30 minutes followed by a gradual decline. Most participants reported similar patterns at both NAC visits, though some did not demonstrate the same phenotype at both visits. Some experienced a secondary symptom rise 24 hours following NAC. Eosinophil and cytokine sections followed a similar pattern at both NAC visits.ConclusionNAC is an adequate method for modelling AR in humans, demonstrating appropriate repeatability of symptoms, nasal mucosal eosinophil and cytokines. The 24h time point, previously not studied in our model, may be beneficial in evaluation of long acting medications. This 3 week interval NAC model will be beneficial for studies where before and after treatment comparisons are desired.
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