The place of lipid transfer proteins (LTP) in the cross-reactivity of plant foods

Abstract

Plant non-specific lipid transfer proteins (nsLTP) are a family of small polypeptides involved in plant defence mechanisms. They possess a compact structure stabilized by four disulphide bridges that confer them a high stability to both thermal treatment and proteolytic digestion, properties that make them true food allergens. Several members of this family have been identified as clinically relevant plant food allergens. Rosaceae fruits are the foods most frequently involved in allergic reactions in patients sensitized to nsLTP, and Pru p 3, the peach nsLTP, seems to be the primary sensitizer in most cases, and can be used as a marker allergen. Since this family of allergens is widely distributed in the plant kingdom and a high degree of IgE cross-reactivity exists among their members, it is common that patients allergic to nsLTP react to a wide variety of plant foods including non- Rosaceae fruits, tree nuts, and vegetables. Due to their high stability, nsLTP are able to induce systemic reactions, especially frequent in those patients who do not have an associated pollen allergy. There is a specific and still unexplained geographical distribution pattern of allergies to nsLTP, that are almost exclusively found in the non-birch pollen areas of the Mediterranean, where nsLTP are the major plant food panallergens.