Glossary beginning with A
A substance that enhances the body's immune response to an antigen. Often used in vaccines.
Any natural or synthetic antigen (usually a protein) that is capable of producing an IgE-mediated immune response. All allergens are antigens, but not all antigens are allergens. Allergens specifically elicit an IgE antibody response (Type I hypersensitivity), while an antigen can elicit any kind of antibody response (such as IgG).
- allergenic extract
A preparation obtained through the extraction of a raw biological source material with an appropriate extracting fluid. The four forms of allergenic extract commonly used are glycerinated, lyophilized, aqueous, and alum-precipitated.
A process whereby the allergens in an aqueous extract are bound to an aluminum salt complex (such as aluminum hydroxide), which is used as an adjuvant. The adjuvant nature of this formulation allows for it to elicit a larger immunological response with a smaller dose. In addition, the alum-allergen complex produces a depot effect, where the allergen is slowly released into the body. Because of its slow release, this formulation is often better tolerated among highly sensitive patients compared to conventional extracts.
- Amb a 1
A major allergen of short ragweed pollen. Short ragweed extracts are labeled with AgE concentrations (now called Amb a 1) as calculated through a standardized assay. These numerical values allow a practice to target short ragweed doses that were found to be efficacious in clinical studies.
An immediate, severe hypersensitivity reaction caused by a systemic (full body) allergic response. The systemic release of histamine and other allergic mediators can result in a significant drop in blood pressure as well as tightening of the throat that can be fatal if not treated immediately. The standard treatment is an immediate injection of epinephrine that will raise blood pressure and decrease swelling, followed by observation and potentially hospitalization. This is a critical medical condition that requires immediate treatment.
Any natural or synthetic substance capable of eliciting an antibody or cell-mediated immune response, or both. All allergens are antigens, but not all antigens are allergens. Allergens specifically elicit an IgE antibody response (Type I hypersensitivity), while an antigen can elicit any kind of antibody response, such as an IgG response in the case of bacterial infection.
A water-based solution, typically saline, that includes a bacteriostatic agent such as phenol to maintain sterility. This is in contrast to a glycerin-based solution.
- aqueous extract
An extract of allergens in an aqueous (i.e. water-based) solution. This is in contrast to a glycinerated extract, which is in a glycerin-based solution.
A condition of hyperreactive airways (bronchi). This includes bronchial constriction, inflammation and hypersecretion of mucus. Allergy and asthma are intimately connected disorders that can be traced to a common inflammatory dysfunction. The presence of childhood allergies, especially to chronic allergens, such as dust mite or mold, is a strong predictor of later asthma symptom development and worsening prognosis.
An early potency unit that expresses the relative biologic activity of an allergenic extract compared to a standard. The label AU has been replaced by BAU, with the exception being House Dust Mite. Allergy units are not directly interchangeable with either PNUs or w/v measures since each of these relies on different methods and criteria.