Abstract
BackgroundThe GA2LEN chamber has been developed as a novel mobile allergen exposure chamber (AEC) allowing standardized multicenter trials in allergy. Hitherto, subjective nasal symptom scores have been the most often used outcome parameter, but in standardized modern trials objective parameters are preferred. Despite its practicability, the objective parameter peak nasal inspiratory flow (PNIF) has been rarely used for allergy trials in the setting of allergen exposure chambers. This study aims to evaluate PNIF as an outcome parameter for provocation studies in AECs.MethodsIn a randomized controlled blinded setting subjects suffering from allergic rhinitis were exposed to grass pollen, birch pollen, house dust mite and/or placebo in the GA2LEN chamber. Different allergen concentrations were used to evaluate symptom severities. Patients had to perform PNIF before and every 30 min during a challenge using a portable PNIF meter.Results86 subjects participated in 203 challenges, altogether. House dust mite provocations caused the greatest reduction in PNIF values, followed by grass pollen and birch pollen. Provocations with every allergen or pollen concentration led to a significant decrease (p < 0.05) in PNIF compared to baseline. Furthermore, positive correlations were obtained between PNIF and peak expiratory flow, height and weight, and inverse correlations between PNIF and total nasal symptom score, nasal congestion score and visual analog scale of overall subjective symptoms.ConclusionPNIF is a helpful and feasible tool for conducting provocation trials with allergens, especially grass pollen and house dust mite, in an AEC.
Highlights
The Global Asthma and Allergy European Network (GA2LEN) chamber has been developed as a novel mobile allergen exposure chamber (AEC) allow‐ ing standardized multicenter trials in allergy
We focus on data from exposures for at least 120 min regarding grass/birch pollen and 90 min for house dust mite (HDM)
The relative peak nasal inspiratory flow (PNIF) compared to baseline (PNIF%) reduction was 29.7%, 95% CI (20.1, 32.8) for 4000 grains/m3, 36.8%, 95% CI (27.8, 43.8) for 8000 grains/m3 and 8.9%, 95% CI (1.3, 15.7) for placebo (Additional file 1: Table S1)
Summary
The GA2LEN chamber has been developed as a novel mobile allergen exposure chamber (AEC) allow‐ ing standardized multicenter trials in allergy. Despite its practica‐ bility, the objective parameter peak nasal inspiratory flow (PNIF) has been rarely used for allergy trials in the setting of allergen exposure chambers. The amount of pollen each subject gets exposed to depends on several uncontrollable factors like climate, lifestyle and the actual pollen load in the air [12] To overcome these difficulties, allergen exposure chambers (AEC) were developed and have been used for years in Europe, North America and Asia [13]. Out of the three most common methods to objectify nasal symptoms, namely rhinomanometry, acoustic rhinometry and peak nasal inspiratory flow (PNIF), the PNIF has been rarely used in the allergen chamber setting It is cheap, portable and provides highly reproducible results despite depending on the patients’ cooperation [15]. Associations between PNIF and biometric data (age, weight, height), PNIF and oral peak expiratory flow (PEF), and PNIF and subjective symptom scores and visual analog scales (VAS) are investigated
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