Is it possible to treat peanut allergy by oral tolerance induction protocols?

Peanut allergy is one of the commonest food allergies in children and has a low natural recovery rate. It is severe and possibly causes fatal anaphylaxis. Current treatment is limited to strict eviction which, although it prevents accidents, does not abate sensitization and the risk of recurrence remains. A risk of increased sensitization has been demonstrated for milk and egg allergy in a randomized study comparing eviction with an oral tolerance induction protocol. Trials evaluating injectable immunotherapy could only be conducted when recombinant allergens, mutated to remove decisive B cell epitopes, would become available. Induction of specific oral tolerance is possible in experimental models. Studies in allergic children whose allergy resolved spontaneously have showed immunological modifications involving Th1-Th2 balance and indicating the role of regulatory T-lymphocytes. However, the slow natural evolution of food allergy in children justifies a therapeutical intervention consisting in daily administration of increasing doses of the food to reach the amount normally eaten. This aims to trigger, or accelerate, immunological tolerance. Studies on egg, milk and wheat flour allergies have produced satisfactory results, indicating a possible application to peanut allergy. This paper summarizes the main facts concerning natural oral tolerance mechanisms, the development of food allergy and spontaneous recovery, before considering specific oral tolerance induction protocols. Criteria of selection of patients are discussed. Protocol implementation modalities are presented, including the increment of doses, the duration of the treatment, parameters for the specific monitoring and later prescription concerning maintenance doses. (C) 2007 Elsevier Masson SAS. Tons droits reserves.