IgE-mediated hypersensitivity reactions

The immunologic mechanisms responsible for allergic reactions are well studied and are among the best defined of any immunopathologic disorder. New knowledge is expanding rapidly, and the type I Gell and Coombs immediate hypersensitivity reaction, which is the basis of the IgE-mediated allergic disease, is more accessible to accurate diagnosis and specific therapy than ever before. The mechanisms of the immediate, late-phase, and dual reactions are discussed. The role of the cyclic nucleotide system, nonimmune mast cell degranulation, and participation of cytokines in atopic allergy are investigated. The principles and pitfalls of specific immunotherapy are reviewed briefly.