Comparison of symptoms during a conjunctival provocation test (CPT) and a controlled exposure to birch pollen in the Strasbourg Environmental Exposure Chamber (EEC) ( ALYATEC)
Monday, March 5, 2018
South Hall A2 (Convention Center)
Ibrahim Choual, Carmen Radu, Naji Khayath, Nicole Beck, Florian Schoettel, Audrey Jacob, Nathalie Domis, Frederic J. de Blay, MD
RATIONALE: As recommended by the task force (Pfaar O et al. Allergy 2017) we compared the results obtained during allergen exposure in EEC with the reference conjunctival provocation test.

AIM : To compare clinical scores obtained during the CPT and in the EEC.

METHODS: 16 patients with an allergic conjunctivitis to birch pollen were selected. They had a positive CPT to birch pollen. They were exposed on 2 consecutive days to nebulized birch pollen in the EEC. Abelson score were performed before and every ten minutes during the 240 minutes of exposure. Challenges were considered positive when Abelson score ≥ 5.

RESULTS: Among 16 positive CPT, 12 subjects had a positive challenge in the EEC. The mean Abelson score was 6.2 with CPT and 5.8 on day 1 and 5.5 on day 2. A positive response was faster obtained with the CPT (36 ±15min) compared to EEC (92± 15min) (p=0.0001). The mean cumulative amount of Bet v1 inducing a positive CPT was 8759.5 ng ±7000 vs 0.2 ng ± 0.12 in the EEC (p=0.0001).

CONCLUSIONS: 75% of positive CPT was also positive in EEC. There was a difference in amount of Bet v1 responsible of positive response in CPT and in EEC. The amount in the EEC is closer to the natural exposure (20 to 60 pollen grains) than the individual CPT. ALYATEC’s EEC is a good tool to assess anti-conjunctival drugs