Pharmacological Mediators of Allergy

Abstract

In allergic reactions a more or less stereotyped response follows contact of a sensitive tissue with a specific substance — the allergen. Allergens are not always chemically defined compounds, consisting as they do of either proteins or other macromolecules, foreign to the body, or modified by acting as haptens. An almost infinite variety of substances can, in susceptible individuals, act as allergens; the response of these individuals is relatively limited, consisting as it usually does of a recognizable clinical syndrome such as asthma, rhinitis, eczema, other rashes or anaphylactic shock. It is a fundamental feature of allergic disease that the nature of the clinical manifestation is not specific to the allergen. The common response can be mimicked in certain respects by administration of endogenous pharmacological agents to normal subjects. Histamine pricked into the skin, for example, causes a weal and flare reaction very similar to that seen in allergic individuals responding to prick tests with appropriate allergens. Such observations led to the idea that histamine and other endogenously released chemical mediators may be involved in various types of allergic reaction1 This has proved a quite fruitful approach, particularly in the case of Type I, anaphylactic reactions. It has thrown some light on the action of drugs effective in allergy.