title: Drug allergy: causes and desensitization.
abstract: Allergic drug reactions occur when a drug, usually a low molecular weight molecule, has the ability to stimulate an immune response. This can be done in one of two ways. The first is by binding covalently to a self-protein, to produce a haptenated molecule that can be processed and presented to the adaptive immune system to induce an immune response. Sometimes the drug itself cannot do this but a reactive breakdown product of the drug is able to bind covalently to the requisite self-protein or peptide. The second way in which drugs can stimulate an immune response is by binding non-covalently to antigen presenting or antigen recognition molecules such as the major histocompatibility complex (MHC) or the T cell receptor. This is known as the p-I or pharmacological interaction hypothesis. The drug binding in this situation is reversible and stimulation of the response may occur on first exposure, not requiring previous sensitization. There is probably a dependence on the presence of certain MHC alleles and T cell receptor structures for this type of reaction to occur.
authors.affiliation: Section of Allergy & Clinical Immunology, Department of Internal Medicine, University of Manitoba, Winnipeg, MB, Canada. rwarrington@hsc.mb.ca
authors.forename: Richard
authors.initials: R
authors.lastname: Warrington
mesh_terms: D017951:Antigen Presentation / Q000276:immunology; D003888:Desensitization, Immunologic; D004342:Drug Hypersensitivity / Q000209:etiology* / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism
chemical_list: D011948:Receptors, Antigen, T-Cell