title: Platelet-activating factor: a possible mediator of the dual response to allergen?
abstract: Certain allergic asthmatic patients exhibit a dual response in the lung following bronchial challenge with the appropriate allergen. Often this is paralleled by a cutaneous dual response when the antigen is injected intradermally. The mechanisms underlying such phenomena are not established, but some evidence suggests that the late response is a consequence of the early response. Since platelet activation has been observed following antigen challenge in asthmatic subjects, we have studied the ability of platelet activating factor (PAF-acether, AGEPC) to induce cutaneous inflammatory responses in man. In a time course study over 24 hr, PAF-acether produced a biphasic response: an immediate weal and flare reaction, which resolved within 1-2 hr and was followed some 3-6 hr later by a delayed reaction in which erythema associated with hyperalgesia was evident. These observations suggest that PAF-acether should be considered in the context of allergic asthma as a possible mediator of the dual response to allergen.
mesh_terms: D000328:Adult; D000485:Allergens / Q000494:pharmacology; D001249:Asthma / Q000209:etiology / Q000276:immunology*; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology; D008297:Male; D010972:Platelet Activating Factor / Q000276:immunology*; D012882:Skin Tests; D013997:Time Factors
chemical_list: D000485:Allergens; D010972:Platelet Activating Factor