Cutaneous basophil hypersensitivity

Cutaneous basophil hypersensitivity is a distinct form of hypersensitivity reaction with a delayed-time course that is different from both the classic delayed-type hypersensitivity reaction and immediate hypersensitivity reaction. It occurs in humans, guinea pigs, and other animals. It may be induced by sensitization with a variety of antigens (viruses, allografts, parasites, fungal antigens, etc.) in incomplete Freund's adjuvant and elicited by skin testing 7 days later with the specific antigens. The cutaneous reaction in basophil hypersensitivity is characterized clinically by less indurated erythema than in classic delayed hypersensitivity, and microscopically by numerous basophils in the papillary dermis. The reaction is mediated by both T- and B-lymphocytes. A basophil chemotactic factor as a mediator of the reaction has also been identified. The reaction may be inhibited by Fc fragments. Basophils on arrival at the local site may degranulate and the released vasoamine may have protective or regulatory effects depending on particular circumstances.