Allergic Response

Abstract

The term hypersensitivity refers to diseases caused by an immune response, regardless of whether the response is against a pathogen, nonpathogen, or self and regardless of whether the response is directed by antibodies, lymphocytes, or innate pathways. The term anaphylaxis was coined in 1902 by Charles Richet, who received the Nobel Prize in 1913; this systemic allergic response is now known to be an immediate hypersensitivity reaction, initiated by allergen delivered to a host having allergen-specific IgE, thereby causing an IgE-mediated immunologic response and activating mast cells and basophils to secrete bioactive mediators. In 2005, the National Institutes of Health organized a consensus conference to develop a working definition of anaphylaxis, designed to be used by physicians at the bedside, as a serious allergic reaction that is rapid in onset, typically eliciting various combinations of cutaneous, cardiovascular, respiratory, and gastrointestinal manifestations, and may cause death.1,2 This facilitated the early treatment of such patients with epinephrine. Confusion arises over the misapplication of the term allergy or hypersensitivity to describe any untoward reaction to food, medications, or environmental exposures. Furthermore, non–IgE-mediated forms of local and systemic mast cell or basophil activation events can occur, causing signs and symptoms similar to those mediated by IgE. This review contains 3 figures, 9 tables, and 62 references. Keywords: allergy, hypersensitivity, anaphylaxis, interleukin, chemokines, immunoglobulin E, mast cell, eosinophil