Mediators of Anaphylaxis, Anaphylactoid Reactions, and Rhinitis

Abstract

Besides histamine, a large and increasing number of mediators of allergic reactions are being found to be released by mast cells or basophils during anaphylactic reactions. Many of these same substances are released by stimuli other than allergen-IgE interactions, and this type of phenomenon (anaphylactoid or pseudo-allergic reaction) may account for some nasal symptoms that simulate allergy. In addition to rapidly developing reactions of these types, numerous recent investigations have emphasized the importance of late-phase reactions that occur as a consequence of the immediate reactivity. Besides mast cells and/or basophils, these late effects seem to involve a complex network of cellular interactions, which may include neutrophils, eosinophils, lymphocytes, macrophages, and platelets.Studies of nasal washings following allergen challenges in humans have provided cogent in vivo support of earlier hypotheses about mediator release based on in vitro experimentation.