Which type of antibody is most involved in allergic reactions?

The antibody most involved in allergic reactions is IgE. This immunoglobulin plays a crucial role in the body’s immune response to allergens. When an individual who is sensitized to a specific allergen is re-exposed to that allergen, IgE antibodies bind to it and trigger the activation of mast cells and basophils. This activation leads to the release of histamines and other inflammatory mediators, which are responsible for the symptoms associated with allergic reactions, such as itching, swelling, and bronchoconstriction.

IgE's primary function is related to the defense against parasitic infections, but it is most well-known for its role in hypersensitivity reactions, including allergic responses to pollen, dust mites, and certain foods. This corresponds to the fact that individuals with allergies have elevated levels of IgE in their serum when compared to those who do not have allergic sensitivities.

The other immunoglobulins mentioned have different roles in the immune system. For example, IgA is primarily involved in mucosal immunity and is found in secretions such as saliva and tears, while IgD is mainly a receptor on B cells and has a less defined role in immune responses. IgM is typically the first antibody produced in response to an infection