The route of sensitization in food allergy

Abstract

Food allergy is an increasing problem in industrialized countries. The mechanisms of allergic sensitization, an immunological phase in which basophils and mast cells acquire IgE antibodies on their surfaces, are well understood. However, the route of sensitization in food allergy is incompletely comprehended. This paper reviews the different routes of sensitization. Although the oral route was described as the main route of sensitization in food allergy previously, it seems that food allergens do not use this route of sensitization predominantly. The dual-allergen-exposure hypothesis suggests that exposure to food allergens via the oral route results in the development of oral tolerance, whereas exposure to food allergens through the skin and/or the respiratory tract results in sensitization. Although this hypothesis has not been confirmed yet, it is assumable that barrier defects in the skin contributes to sensitization to food allergens. Loss-of-function of filaggrin, an important component of the epidermal barrier, is associated with sensitization to peanut allergens. Further research will prove if this is also true for other types of food allergen. Since it has been discovered that food allergens can be inhaled, it is plausible that barrier defects of the respiratory tract, such as dysfunction of PCDH1, also play an important role in sensitization to food allergens. However, more studies are necessary to prove this. In conclusion, we can distinguish three routes of sensitization: the oral, cutaneous, and respiratory route. However, it has to be investigated whether barrier defects in the skin and the respiratory tract are associated with sensitization to food allergens or not.