Allergy laboratory

The Allergy Laboratory

Summary

Science

Laboratory

Scientist

Science

Allergies are sometimes called type 1 hypersensitivity reactions and they occur because certain people have more of a special type of antibody called IgE. Specialised cells called mast cells in the tissue and basophils in the blood rapidly take up the IgE molecules. When an individual has been sensitised to an environmental substance and made specific IgE antibodies, subsequent exposure to the allergen results in the cross bridging of the IgE antibodies on the surface of the mast cells and basophils. These cells then explode releasing pre-formed mediators, stimulating the production of more mediators. It is these mediators that provoke the signs and symptoms of the allergic response. The extent of reaction is heavily dependent on the nature of the allergen. A lot of antigens (allergens) that are inhaled or ingested provoke only local reactions in the upper and lower respiratory tracts (rhinitis and Asthma) and gastro intestinal tract. However some ingested antigens such as peanuts, and others like insect venom that are injected cause a much more severe reaction called anaphylaxis. Anaphylaxis frequently presents as a combination of systemic symptoms including low blood pressure, rashes, constriction of the airways, and swelling of the lips and mucous membranes. Whilst treatable if caught early, these symptoms can be fatal in the severest of cases. Identification of specific allergic antigens that could be avoided is important because of the potential for severe reactions in some patients as well as the reduction in quality of life in patients with less severe but more persistent symptoms.

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