Allergen-specific IgE production and dissemination

Allergens (in this figure, aeroallergens) enter the tonsils within which they are taken up and degraded by antigen-presenting cells (APCs). APCs then interact with T helper type 2 (Th2) cells and B cells in the lymph nodes, leading to allergen-specific IgE production. The IgE enters the bloodstream and then diffuses through tissues (especially the skin and mucosal tissues of the respiratory and gastrointestinal tracts). The IgE binds to high-affinity Fc receptors (Fc-epsilon-RI) on the surface of the tissue mast cells and circulating basophils. When these IgE-coated cells encounter that specific aeroallergen subsequently, they become activated, leading to the release of inflammatory mediators, which results in the signs and symptoms of IgE-mediated allergic reactions.