Features and mode of action of cross-reactive plant allergens relevant to latex-fruit syndrome

Immediate-type reactions to articles made from natural rubber latex are collectively referred to as latex allergy. Some latex-sensitized patients also experience allergic reactions to various fruits and vegetables. This phenomenon is called latex-fruit syndrome. Recent research revealed that several proteins related to the defense mechanisms of plants are responsible for latex allergy and the accompanying cross-reactivity. Protective systems of higher plants are relatively conserved in the course of evolution, and therefore homologous defense-related proteins are produced regardless of the species. Once sensitized by such a conserved protein, the patient is expected to cross-react to taxonomically unrelated plants. Remarkably, cross-reactive antigens in the causative foods are generally sensitive to heat and digestive enzymes. Per-oral sensitization is not commonly established by such food antigens. They are instead considered to elicit allergic reactions in latex-sensitized patients based on their cross-reactivity to the corresponding sensitizers. Defense-related proteins in higher plants are agriculturally useful, and various environmental stresses up-regulate their production. These proteins are also suspected to be relevant to the increasing allergies to plants.