Gell and Coombs classification

classification /clas·si·fi·ca·tion/ (klas″ĭ-fĭ-ka´shun) the systematic arrangement of similar entities on the basis of certain differing characteristics.

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adansonian classification  numerical taxonomy.

Angle's classification  a classification of dental malocclusion based on the mesiodistal position of the mandibular dental arch and teeth relative to the maxillary dental arch and teeth; see under malocclusion.

Bergey's classification  a system of classifying bacteria by Gram reaction, metabolism, and morphology.

Caldwell-Moloy classification  classification of female pelves as gynecoid, android, anthropoid, and platypelloid; see under pelvis.

FIGO classification  any of the classification systems established by the International Federation of Gynecology and Obstetrics for the staging of gynecological cancers.

Gell and Coombs classification  a classification of immune mechanisms of tissue injury, comprising four types: 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, local or general inflammatory responses due to formation of circulating immune complexes and their deposition in tissues; and type IV cell-mediated hypersensitivity reactions, initiated by sensitized T lymphocytes either by release of lymphokines or by T-cell–mediated cytotoxicity.

Keith-Wagener-Barker classification  a classification of hypertension and arteriolosclerosis based on retinal changes.

Lancefield classification  the classification of hemolytic streptococci into groups on the basis of serologic action.

New York Heart Association (NYHA) classification  a functional and therapeutic classification for prescription of physical activity for cardiac patients.

Revised European American Lymphoma (REAL) Classification  a classification of lymphomas based on histologic criteria, dividing them into three main categories: B-cell neoplasms, T- or NK-cell neoplasms, and Hodgkin's disease.

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Gell and Coombs classification

[jel; kōōmz]

a classification of immune mechanisms of tissue injury, comprising four types of hypersensitivity reactions: type I (anaphylactic reactions), immediate hypersensitivity reactions mediated by interaction of immunoglobulin E antibody and antigen and release of histamine and other mediators; type II (cytotoxic reactions), antibody-mediated hypersensitivity reactions caused by antibody-antigen interactions on cell surfaces; type III (immune complex reactions), mediated hypersensitivity reactions, local or general inflammatory responses caused by 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.