Immunoglobulin E specific to galactose-alpha-1,3-galactose (Alpha-gal IgE)

Immunoglobulin E (IgE) specific to galactose-alpha-1,3-galactose (alpha-gal) is the primary mediator of Alpha-gal syndrome (AGS), a unique form of delayed-onset food allergy to mammalian meat (Commins et al., 2011). Unlike most food allergies which target proteins, this response is directed against a carbohydrate epitope found on the cell membranes of non-primate mammals (Chung et al., 2008). Sensitization typically occurs following the bite of certain tick species, such as the Lone Star tick (Amblyomma americanum), which introduces the carbohydrate into the human bloodstream (NIH, 2023). Upon subsequent ingestion of red meat or exposure to mammalian-derived products, these IgE antibodies trigger mast cell degranulation, leading to symptoms ranging from urticaria to life-threatening anaphylaxis (Steinke et al., 2015). In clinical practice, these antibodies are also responsible for immediate hypersensitivity reactions to the monoclonal antibody cetuximab, which contains the alpha-gal epitope on its Fab portion (Chung et al., 2008). Therapeutic strategies involve the use of anti-IgE agents like omalizumab to reduce the allergic response or strict avoidance of mammalian products (Apostolovic et al., 2015).

Other names

Anti-alpha-gal IgEIgE to galactose-alpha-1,3-galactoseAlpha-gal antibodiesMammalian meat allergy IgE

Omalizumab binds to the Cε3 domain of free IgE, including alpha-gal specific IgE, preventing its interaction with the high-affinity IgE receptor (FcεRI) on mast cells and basophils, thereby inhibiting the allergic cascade triggered by alpha-gal epitopes (Apostolovic et al., 2015).