The aim of this study is to assess the nasal and conjunctival response in subjects allergic to birch pollen during controlled exposures in the ALYATEC environmental exposure chamber (EEC)

This is a single-center, single-blind, placebo-controlled study. The first part of the study consists of 6 exposure sessions in Alyatec EEC, including placebo and birch pollen allergen exposures.

The second part of the study involves in-field evaluations of rhinitis and conjunctivitis symptoms during birch pollen season.

Alyatec environmental exposure chamber, also called allergen challenge chamber, allows to evaluate allergic symptoms in standardized and reproducible conditions. All the metrological parameters (temperature, air flow, hygrometry ...) are controlled as well as the allergen concentration diffused in the room.

This enables to induce and observe rhinitis, conjunctivitis and asthma symptoms for up to 20 patients at the same time, in a reproducible way and without the potential perturbations or contaminations of the natural environment.

The current study aims to get specific information about allergic symptoms induced in the Alyatec EEC chamber in patients sensitized to birch pollen allergen.

Inclusion Criteria:

• A clinical history of allergic rhinitis to birch pollen for at least 2 consecutive pollen seasons requiring the taking of a symptomatic drug with or without associated asthma
• Positive skin prick tests for birch pollen (> 3 mm)
• IgE specific to birch > 0.75 kUI / L.
• Positive unit rapid nasal provocation test for birch pollen
• Subjects having signed informed consent
• Subjects affiliated to a social security scheme
• Subjects able to understand and complete the procedures related to the study
• Women of childbearing potential should have a negative pregnancy test throughout the study period with effective contraception

Exclusion Criteria:

• Specific immunotherapy (SIT) for birch allergens for more than a month in the 3 years preceding the screening
• Current use of Specific immunotherapy for another allergen
• Medical history of anaphylaxis following exposure to birch pollen
• Medical history of anaphylaxis linked to another allergen in the last 6 weeks
• Nasal polyps, nasal septum deviation or diagnosis of non-allergic rhinitis
• Subjects allergic to indoor environmental allergens (cat allergens, mold, dust mites) with - Obvious exposure to these allergens.
• Uncontrolled allergic pathology (rhinitis, conjunctivitis)
• Forced expiratory volume in 1 second (FEV1) <70% of predicted normal values
• Moderate to severe asthma (GINA 3 to 5)