reagin

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.

[REAG(ENT) + -IN.]

Noncommittal term used for antibodies or antibodylike 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.

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.

An old term for immunoglobulin E antibody (IgE).

• atopic r. — the antibody responsible for hypersensitivity reactions to specific substances with signs of atopy resulting.

The noun has one meaning:

Meaning #1: an immunoglobulin E that is formed as an antibody against allergens (such as pollen); attaches to cell membranes causing the release of histamine and other substances responsible for the local inflammation characteristic of an allergy