Allergies alimentaires : mécanismes physiopathologiques, identification des allergènes alimentaires

Abstract

Food allergy is an immunologically mediated adverse reaction to foods which only affects genetically predisposed individuals. In the general population of adults, the prevalence is about 3.5% while it is 5–8% in children but an increase is observed and the severity of the clinical manifestations is also increasing. The allergic reaction develops in two steps. The sensitization occurs at the first contact with the allergen without any symptoms. A second contact elicits the reaction, then the release of mediators and the onset of clinical manifestations. Allergenic foods are numerous and vary according to the dietary habits of the groups of population who are affected but about 12 foods are responsible for most of the food allergies. Each allergenic food contains several constituents, i.e. proteins, that are responsible for the allergenicity and within each allergen many immunoreactive regions, i.e. epitopes, are spread all over the protein molecule. The variability of the immune response of allergic humans to those different compounds makes the prediction of allergenicity of a new food uncertain but the characterization of allergenic structures in foods allows to better understand some of the pathophysiological mechanisms of the allergic reaction.