Apple-birch pollen-food allergy syndrome is particularly common in Northern and Central Europe (70% of patients allergic to birch pollen), and classically induces an oral syndrome that impairs patients' quality of life. Current treatment is based on food avoidance. However, evidence of the efficacy of this treatment is limited (small numbers, lack of validation with a control group, absence of double-blind evaluation of the primary endpoint in a challenge test against placebo). The aim of oral immunotherapy with raw apple is to improve the management of allergic patients by enabling them to acquire tolerance to raw apple and other rosacea.

Inclusion Criteria:

• Patient with allergic rhinitis to birch pollen.
• Patient with an oral syndrome within 15 minutes of consuming at least one of the first 3 doses of raw apple in the V0 or V1 raw apple oral challenge test.
• Evidence of sensitization to PR10 proteins in birch pollen and apple: positive prick tests to birch pollen and raw Golden apple and/or positive Bet v 1 and Mal d 1 specific IgE assays.
• Subject affiliated to a social health insurance scheme
• Subject able to understand the aims and risks of the research and to give dated and signed informed consent
• For women of childbearing age: negative urine pregnancy test at inclusion visit

Exclusion Criteria:

• Severe or uncontrolled asthma
• Severe obstructive syndrome
• Active neoplastic disease
• Active autoimmune disease
• Eosinophilic esophagitis or other active eosinophilic gastrointestinal pathologies
• History of bariatric surgery
• History of anaphylaxis to apples
• Allergy to cooked apples
• Contraindication to anti-histamines, corticoids, salbutamol, adrenaline
• Other contraindication to an oral challenge test
• Allergy to placebo ingredients
• Presence of oral syndrome during consumption of placebo in the first oral challenge test
• Allergenic immunotherapy to birch pollen in progress or completed less than 5 years ago
• Current treatment with anti-IgE, anti-IL4/13, anti-IL5 or anti-TSLP biotherapy.
• Impossibility of giving the subject informed information
• Subject under court protection
• Subject under guardianship or curatorship
• Pregnancy