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Abstract: 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. [Copyright &y& Elsevier]

Nous rapportons une observation d''asthme lié à l''arachide chez un enfant de trois ans. Le diagnostic a été établi fortuitement. L''éviction rigoureuse de l''arachide a entraîné une régression complète des symptômes et un arrêt rapide du traitement inhalé. La sévérité de l''allergie à l''arachide chez l''enfant asthmatique est liée au risque d''anaphylaxie. Il nous paraît alors utile de rechercher une allergie à l''arachide chez tout enfant atteint d''asthme sévère pour obtenir un meilleur équilibre de l''asthme et prévenir une éventuelle anaphylaxie. [Copyright 2004 Elsevier]

Peanuts are one of the allergens most often responsible for food allergy . Nevertheless, the occurrence of peanut allergy varies between countries and appears to result from both the amount of peanuts in the diet and the way they are consumed. In addition, processing influences the allergenicity of peanut proteins. The aim of the present study was to examine the effect of some thermal processes on the IgE binding capacity of peanut allergens, using sera of patients allergic to peanuts. Protein extracts were prepared from raw, roasted and boiled peanuts. In each case, the proteins were isolated, purified and characterised by electrophoresis. The immunoreactivity of each protein extract was analysed using the Enzyme Allergo Sorbent Test (EAST) and EAST inhibition with sera from 37 peanut allergic patients. Western blots were also performed. The biochemical analysis of the whole protein extracts revealed slight modifications in the protein composition, particularly after boiling. The IgE binding capacity of the boiled peanut protein extract was reduced by 50% compared to raw and roasted peanut extracts. This difference on the recognition of peanut allergens by patients’ IgE was confirmed by the inhibition assays. Impaired IgE recognition mainly involves proteins of low molecular weight. No difference in immunoreactivity was observed between raw and roasted peanut protein extracts. Roasting peanuts does not modify their allergenicity while boiling decreases it considerably. This decrease of boiled peanut allergenicity comes from a loss of some allergens into the boiling water. It may also be due to structural modifications of peanut proteins that occur in boiling water. [Copyright &y& Elsevier]

The frequency of allergic reactions to peanut and tree nuts has increased. The cumulated prevalence of peanut allergy is high, 0.5 to 1.2% in American and Western European children; the prevalence of tree nut allergy is 0.5%. Allergic reactions to peanut and tree nuts can be life threatening. This problem is widely discussed in the media. Sensitization to tree nuts should be investigated in children with allergy to peanut or to any other nut. Evaluation  of the patient must take into account the clinical data and the results of skin tests, specific IgE assays and labial provocation tests. The decision of whether to perform a provocation challenge should be individualized. Children, particularly adolescents, at risk for severe reactions include those with multiple allergies, asthma, especially uncontrolled asthma, or facilitating factors such as drugs (including aspirin), alcohol and exercice. At present, prevention calls for avoidance of peanuts and tree nuts. Global management and careful education are essential and should be tailored to each child and its family. Management of severe food allergies must be comprehansive and must consist of more than just epinephrine. [Copyright &y& Elsevier]

Eric is a 7-year-old boy with no personal history of food allergy. His mother asked us to carry out an oral challenge test because his homozygous twin brother had an allergic reaction to cashew nuts several years before. This interesting observation gives us an opportunity to review recent data on risk factors, cross-reactions and diagnostic procedures when confronted with a patient suspected of being allergic to peanuts. [Copyright &y& Elsevier]

Abstract: The authors report the case of a child allergic to peanuts since he was one year old who, at the age of 9 years, developed angioedema after playing with his "Play Station". This device had been used previously by his uncle who had eaten peanuts at a family get-together. This observation illustrates a new way of transmitting food allergies and provides an opportunity to review the principal situations in which this allergy can be transmitted by proxy. [Copyright &y& Elsevier]

Abstract: The prevalence of food allergy continues to increase. Changes in our eating habits, physico-chemical modifications of food proteins with the development of new agro-food technologies have changed the distribution of food allergens. The important food allergens in 2007 are peanut, cashew nut, sesame, kiwi, protein hydrolysates, and sheep and goat milk. But the list is not exhaustive. The European codification of ingredients, the agro-food industry and the public powers must take into consideration the emergence of new allergens in control of labeling of final products. [Copyright &y& Elsevier]