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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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The immunoglobulin involved in type 1 hypersensitivity reactions is
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The correct answer is  Ref Robbins 9/e p202 Immediate hypersensitivity is a tissue reaction that occurs rapidly (typically within minutes) after the interaction of antigen with IgE antibody that is bound to the surface of mast cells in a sensitized host. The reaction is initiated by entry of an antigen, which is called an allergen because it triggers allergy. Many allergens are environmental substances that are harmless for most persons on exposure. Some people apparently inherit genes that make them susceptible to allergies. This susceptibility is manifested by the propen- sity of such persons to mount strong TH2 responses and, subsequently, to produce IgE antibody against the aller- gens. The IgE is central to the activation of the mast cells and release of mediators that are responsible for the clinical and pathologic manifestations of the reaction. Immediate hypersensitivity may occur as a local reaction that is merely annoying (e.g., seasonal rhinitis, or hay fever), severely debilitating (asthma), or even fatal (anaphylaxis).