Allergic response (None)

The *allergic response* is an immune system overreaction triggered when harmless environmental substances called allergens cross-link allergen-specific Immunoglobulin E antibodies bound to the high-affinity receptor Fc epsilon RI (**FcεRI**) on mast cells and basophils. This cross-linking activates these effector cells causing rapid degranulation releasing preformed mediators like histamine along with newly synthesized leukotrienes and cytokines. The immediate phase leads to symptoms ranging from mild irritation in hay fever to severe systemic anaphylaxis. A late-phase inflammatory reaction follows involving recruitment of TH2 lymphocytes, eosinophils, and basophils which contribute further tissue damage characteristic of chronic allergy. Recent research has identified additional mechanisms contributing to allergic sensitization such as interleukin IL‑3 produced by specialized skin immune GD3 cells that prime sensory neurons for heightened reactivity without directly causing itchiness[3]. This highlights potential novel therapeutic targets beyond classical pathways. In summary, while "Allergic response" itself is not a singular molecular target but rather an integrated physiological process involving multiple cellular actors—mast cell FcεRI receptor being central—it remains critical for understanding allergy pathogenesis and guiding targeted therapies[1][4][3].

Other names

Hypersensitivity reactionIgE-mediated hypersensitivityImmediate-type hypersensitivity

Drugs act by: - Blocking histamine receptors to reduce symptoms like itching and swelling. - Preventing IgE from binding FcεRI thereby inhibiting mast cell activation. – Suppressing cytokine signaling pathways that promote recruitment/activation of eosinophils/basophils.