Regarding hypersensitivities, the diversity of their clinical manifestations prompt us to focus on homogeneous groups of patients and we thus wish to concentrate on two groups of patients who are frequently referred to the hospital: severe allergies to Hymenoptera venoms and severe food allergies related to peanut allergens sensitization. These groups will be built by considering multiple clinical criteria (clinical history, severity of the manifestations, positive skin tests, and positive oral provocation tests for peanut allergens…) and biological criteria authenticating the mechanisms of the disease (high specific serum IgE, demonstration of specific basophil activation by the allergen…).