reagin

reagin /re·a·gin/ (re´ah-jin) the antibody that mediates immediate hypersensitivity reactions; in humans, IgE.reagin´ic

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re·a·gin (r-jn)

n.

1. An antibody found in the blood of individuals having a genetic predisposition to allergies such as asthma and hay fever.

2. A substance present in the blood of individuals having a positive serological test for syphilis.

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rea·ginic (r-jnk) adj.

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reagin

[rē′ājin]

Etymology: L, re + agere

1 an antibody associated with human atopy, such as asthma and hay fever. It attaches to mast cells and basophils and sensitizes the skin and other tissues. In antigen-antibody reactions it triggers the release of histamine and other mediators that cause atopic symptoms.

2 a nonspecific, nontreponemal antibody-like substance found in the serum of individuals with syphilis. It can combine with an antigen prepared as a lipid extract of normal tissue, a phenomenon that constitutes the basis of the serologic tests for syphilis. reaginic, adj.

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reagin(s) (rē´ājin),

n noncommittal term used for antibodies or antibody-like substances that differ in several respects from ordinary antibodies. It refers to the antibodies of allergic conditions (atopy) and to the antibody (reagin) concerned with the flocculation and complement fixation tests for syphilis.

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reagin

an old term for immunoglobulin E antibody (IgE).

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atopic reagin

the antibody responsible for hypersensitivity reactions to specific substances with signs of atopy resulting.