Non-protein allergen (pectin or erythritol)

Abstract

The majority of food allergens are proteins that possess multiple IgE binding epitopes within their complex macromolecular structures. In contrast, low-molecular-weight substances are regarded as less allergenic due to their simple structures, which render them less likely to elicit an IgE-mediated immune response. Nevertheless, there have been rare instances of allergic reactions documented in individuals who have ingested foods containing low-molecular-weight substances, such as sugar alcohol erythritol or the polysaccharide pectin. These low-molecular-weight non-protein allergens are commonly utilized as food ingredients or as additives and are often not labeled as ingredients, which makes it challenging to identify them as the causative agents of allergic symptoms. The detection of specific IgE to these substances is challenging due to the difficulty in immobilizing them in the assay system. However, skin tests and basophil activation tests may offer a potential solution. This review will focus on non-protein allergens, with a particular emphasis on erythritol and pectin, and will endeavor to provide a useful clue to diagnose these "rare and underrecognized" allergies.