| hypersensitivity, delayed | An increased reactivity to specific antigens mediated not by antibodies but by cells. (12 Dec 1998) |
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| delayed hypersensitivity | <immunology> Hypersensitivity (increased reaction by the body to a foreign substance such as an antigen or allergen) that does not appear until 24 to 48 hours after the body is exposed to the foreign substance. (09 Oct 1997) |
| delayed type hypersensitivity | <immunology> Hypersensitivity (increased reaction by the body to a foreign substance such as an antigen or allergen) that does not appear until 24 to 48 hours after the body is exposed to the foreign substance. (09 Oct 1997) |
| hypersensitivity reaction | <immunology> The bodys response to an allergic stimulus. This can be localised to one area or generalised and may include: rash, itching, hives, swelling, difficulty breathing, and/or low blood pressure. (27 Sep 1997) |
| immediate hypersensitivity reaction | An immune response mediated by antibody, usually IgE, which occurs within minutes after a second encounter with an antigen, resulting in the release of histamine and subsequent swelling and vasodilation. (05 Mar 2000) |
| type III hypersensitivity reaction | An immunologic category of diseases evoked by the deposition of antigen-antibody or antigen-antibody-complement complexes on cell surfaces, with subsequent involvement of breakdown products of complement, platelets, and polymorphonuclear leukocytes, and development of vasculitis; nephritis is common. Arthus phenomenon and serum sickness are classic examples, but many other disorders, including most of the connective tissue disease's, may belong in this immunologic category; immune complex disease's can also occur during a variety of disease's of known aetiology, such as subacute bacterial endocarditis. See: autoimmune disease. Synonym: immune complex disorder, type III hypersensitivity reaction. (05 Mar 2000) |
| delayed reaction | A local or generalised response that begins 24 to 48 hours after exposure to an antigen. See: cell-mediated reaction. Synonym: contact hypersensitivity, delayed hypersensitivity, late reaction, tuberculin-type hypersensitivity. (05 Mar 2000) |
| delayed reaction experiment | A method of measuring memory: a stimulus is presented and removed before the organism is permitted to respond to it; the interval during which the stimulus is absent, providing the organism responds correctly, is an indication of the length of memory. (05 Mar 2000) |
| vasculitis, hypersensitivity | Heterogeneous group of disorders characterised by a vasculitic syndrome presumed to be associated with a hypersensitivity reaction following exposure to an antigen such as an infectious agent, a drug, or other foreign or endogenous substance. (12 Dec 1998) |
| respiratory hypersensitivity | A form of hypersensitivity affecting the respiratory tract. It includes asthma and hay fever. (12 Dec 1998) |
| milk hypersensitivity | Allergic reaction to milk (usually cow's milk) or milk products. In infants the hypersensitivity is manifested by colic, vomiting, diarrhoea, rhinitis, wheezing, etc. Milk hypersensitivity should be differentiated from lactose intolerance, an intolerance to milk as a result of congenital deficiency of lactase. (12 Dec 1998) |
| contact hypersensitivity | <pathology> A type of immune-mediated inflammatory skin rash that results from an allergy to a particular substance (for example jewelry dermatitis, poison ivy, neomycin ointment, etc.). (27 Sep 1997) |
| hypersensitivity | <immunology> A state of altered reactivity in which the body reacts with an exaggerated immune response to a foreign substance. Hypersensitivity reactions are classified as immediate or delayed, types I and IV, respectively, in the Gell and Coombs classification of immune responses. (18 Nov 1997) |
| hypersensitivity, immediate | Hypersensitivity reactions which occur within minutes of exposure to challenging antigen due to the release of histamine which follows the antigen-antibody reaction and causes smooth muscle contraction and increased vascular permeability. (12 Dec 1998) |
| hypersensitivity pneumonitis | <radiology> Aka: chronic extrinsic allergic alveolitis, pathology: proliferation of epithelial cells, elaboration of reticulum fibres, findings: interstitial reticulonodular pattern (basilar distribution), volume loss (cicatrization atelectasis) in upper lobes, pleural effusion (rare), lymph node enlargement may occur (12 Dec 1998) |