Gell and Coombs classification
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Gell and Coombs classification[jel; ko̳mz]
a classification of immune mechanisms of tissue injury, comprising four types of hypersensitivity reactions: type I,immediate hypersensitivity reactions, mediated by interaction of IgE antibody and antigen and release of histamine and other mediators; type II, antibody-mediated hypersensitivity reactions, due to antibody-antigen interactions on cell surfaces; type III, immune complex–mediated hypersensitivity reactions, local or general inflammatory responses due to formation of circulating immune complexes and their deposition in tissues; and type IV cell-mediated hypersensitivity reactions, delayed hypersensitivity reactions initiated by sensitized T lymphocytes either by release of lymphokines or by T-cell–mediated cytotoxicity.
Gell and Coombs Clas·si·fi·ca·tion(gel kūmz),
a classification system that differentiates the four types of hypersensitivity reactions: Type I: anaphylactic reactions, Type II: cytotoxic reactions, Type III: immune complex reactions, and Type IV: cell-mediated/delayed hypersensitivity reactions.