Allergic diseases are conditions in which a patient inhales or ingests substances containing allergenic components (called allergens or allergens, allergen) that trigger the body’s B cells to produce excessive immunoglobulin E (IgE). When IgE antibodies are re-exposed to allergens in vivo, they cross-link with allergens and bind to the higher affinity receptor FcεRI on the surface of mast cells and basophils, resulting in FcεRI accumulation and mast cell and basophil activation. During activation, mast cells degranulate and release histamine, an inflammatory mediator stored in cytoplasmic granules, and leukotrienes, immunoreactive prostaglandins, cytokines and chemokines such as IL-4 and IL-5 synthesized through arachidonic acid pathway, triggering disease symptoms of allergic reactions (or allergic reactions), such as allergic asthma, hay fever, urticaria, allergic rhinitis, eczema, allergic dermatitis, conjunctivitis and gastrointestinal dysfunction. The detection of different kinds of allergen-specific IgE antibodies in serum can be used for auxiliary diagnosis of whether some symptoms are caused by allergy in clinical practice.

Immunoglobulin IgE is an antibody that mediates type I allergic reactions, and allergen-specific IgE is present in the serum of allergic patients, which is called specific IgE. Those allergic to milk have IgE against milk allergens; those allergic to artemisinin pollen have IgE against the pollen. Allergens enter the body to induce the production of specific IgE, which binds to mast cells and basophils, allowing the body to enter a state of specific sensitization to this allergen. When the allergen comes into contact again, it binds to the IgE receptor on the cell membrane and causes a series of biochemical reactions, which subsequently release various bioactive mediators related to allergic reactions and inflammation, such as histamine. Since this antibody can only specifically bind to this allergen, it is necessary to use purified allergen instead of anti-IgE for detection. There are many specific IgE assay methods, such as ELISA, FEIA, and immunoblotting are commonly used in clinical practice.