This clinical validation study is aimed at establishing a birch pollen challenge in the Fraunhofer ECC in patients allergic to birch pollen. The symptoms will be recorded on a validated symptom score as Total Nasal Symptom Score (TNSS), allowing to determine whether the challenge is dose dependent and reproducible.
This is a mono-center, single-blind, placebo controlled study assessing nasal symptoms in patients with allergic rhinitis upon exposure to birch pollen in an environmental challenge chamber during a 4 hour challenge period with different concentrations of birch pollen versus placebo. Subjects with allergic rhinitis to birch pollen will be recruited from the Fraunhofer ITEM database or the surrounding communities. After the screening evaluation eligible subjects will undergo six challenge sessions in the environmental challenge chamber at intervals of at least one week. In order to determine dose response, the concentration of birch pollen in the atmosphere of the challenge chamber will be varied from 1000 birch pollen/m³ in the first period, 2000 birch pollen/m³ in the second period, 4000 birch pollen/m³ in the third period, 8000 birch pollen/m³in the fourth period to 0 birch pollen/m³ (only air) in the fifth period. In order to investigate reproducibility in addition to dose response, a challenge with one concentration previously used will be repeated in period six. The dose will be chosen by the Investigator according to the observed nasal symptoms. According to previous experience with grass pollen (Dactylis glomerata) the target symptom level for TNSS is around 6. Therefore, the dose to study reproducibility will be chosen where the average mean TNSS of the last two hours will be closest to six. If two doses are equally close, the higher dose will be chosen because this will allow to optimize the particle monitoring technique. In this regard, it is better to have a high particle concentration in order to separate specific particles from unspecific particles (originating from the subjects themselves).
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
18
Total Nasal Symptom Score (TNSS)
TNSS measured every 20 minutes over 4 hours of birch pollen challenge in the ECC
Time frame: every 20 minutes
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