High affinity immunoglobulin epsilon receptor (FcεRI) complexed with peanut-specific Immunoglobulin E (IgE) (FcεRI-IgE complex)

The complex formed by peanut-specific Immunoglobulin E (IgE) and the high-affinity IgE receptor (FcεRI) is the central molecular trigger for allergic reactions to peanuts (Galli & Tsai, 2012). In sensitized individuals, B cells produce IgE antibodies that recognize specific peanut allergens, such as Ara h 1, 2, and 3, which then bind to the FcεRI receptors on mast cells and basophils (UniProt, 2023). Upon subsequent ingestion of peanuts, these allergens cross-link the bound IgE molecules, initiating an intracellular signaling cascade through kinases like Lyn, Syk, and Bruton's tyrosine kinase (BTK) (MacGlashan, 2008). This signaling leads to the rapid degranulation of the cells and the release of potent inflammatory mediators like histamine and leukotrienes, which cause the clinical symptoms of peanut allergy, ranging from urticaria to life-threatening anaphylaxis (NIH, 2023). Therapeutic interventions like Omalizumab target this pathway by sequestering free IgE, thereby preventing the formation of new complexes and leading to the gradual downregulation of FcεRI on the cell surface (Wood et al., 2024; FDA, 2024). Additionally, small molecule inhibitors targeting downstream components of this complex, such as BTK, are being explored to block the activation signal even when the complex is present (JACI, 2022).

Other names

Peanut-specific IgE-FcεRI complexIgE-FcεRI signaling complexHigh affinity IgE receptor complexPeanut-specific IgE-FcεRI signaling unit

Sequestration of free IgE to prevent receptor binding; Downregulation of surface FcεRI expression; Inhibition of downstream Bruton's tyrosine kinase (BTK) signaling; Prevention of mast cell and basophil activation.