[Allergy-related hypereosinophilia].

Hypereosinophilia in the blood and tissues is one of the main characteristics of the pathophysiology of allergic disease. CD4+ T cells polarized to a Th2 phenotype mediate inflammatory disorders; cytokines produced by Th2, including IL-4, IL-5, and IL-13, drive the cardinal features of the disease. Recent human experiments indicate that eosinophils may control the bronchial remodeling that occurs in asthma. Eosinophils are a rich source of fibrogenic factors, particularly TGF-ss. Atopy is defined by abnormal IgE production in response to an allergen (an antigen that is then designated an allergen). Allergy combines pre-existent sensitization (atopy) with various symptoms - cutaneous, ENT, respiratory, or digestive. Atopy is diagnosed primarily by cutaneous skin-prick tests and the new multi-allergen blood test. A diagnosis of allergy requires the presence of symptoms and justifies workups for asthma, rhinitis, food allergies, or atopic dermatitis.