Major peanut allergens (Ara h 1, Ara h 2, Ara h 3, Ara h 6) (Ara h proteins)

Major peanut allergens are a group of highly stable proteins derived from the peanut plant (Arachis hypogaea) that are responsible for triggering severe IgE-mediated allergic reactions (WHO/IUIS Allergen Nomenclature). The most clinically significant allergens include Ara h 1, Ara h 2, Ara h 3, and Ara h 6, which belong to the cupin and prolamin protein superfamilies. These proteins function biologically as seed storage reserves but act as potent allergens due to their resistance to heat and proteolytic digestion (PMID: 21235441). In allergic individuals, these proteins cross-link IgE antibodies on the surface of mast cells and basophils, leading to the rapid release of inflammatory mediators that cause symptoms ranging from urticaria to fatal anaphylaxis. Therapeutic interventions like Palforzia utilize these allergens in a controlled, escalating dose format to desensitize the immune system and reduce the risk of severe reactions upon accidental exposure (FDA, 2020). Additionally, monoclonal antibodies such as omalizumab are used to sequester IgE, providing a safety buffer during immunotherapy or reducing the risk of accidental exposure (FDA, 2024).

Other names

Arachis hypogaea allergensPeanut seed storage proteinsAra h 1Ara h 2Ara h 3Ara h 6

Oral immunotherapy (OIT) involves the administration of gradually increasing doses of the allergen to induce clinical desensitization and immune tolerance by modulating T-cell responses and increasing protective IgG4 levels (PMID: 31978277). Adjunctive therapies like omalizumab bind to circulating IgE, preventing it from binding to the high-affinity IgE receptor (FcεRI) on mast cells and basophils, thereby raising the threshold for allergic reactions (FDA, 2024).