Our aim in this study was to evaluate COPs hypoallergenicity in vitro (based on their IgE binding capacity) and in vivo (based on their capacity to induce an allergic reaction in animals or a positive skin test in Bet v 1 allergic volunteers) as a preliminary study to a therapeutic phase I clinical trial in patients with allergic rhinitis to birch pollen. Here, IGHE is linked to allergic disease.