Which immunoglobulin is involved in allergic reactions?

The immunoglobulin involved in allergic reactions is IgE. This specific class of antibody plays a crucial role in the body's immune response to allergens. When an individual is sensitized to a particular allergen, IgE binds to it and triggers the activation of mast cells and basophils. This activation leads to the release of various mediator substances, including histamine, which are responsible for the symptoms of an allergic reaction, such as itching, swelling, and inflammation.

IgE is distinctly associated with hypersensitivity reactions, particularly type I hypersensitivity, which includes common allergies such as hay fever, asthma, and anaphylaxis. The presence of elevated levels of IgE in the serum is often associated with allergic conditions.

In contrast, other immunoglobulin classes serve different roles in the immune system. IgG is primarily involved in long-term immunity and can also neutralize toxins and pathogens. IgM is the first antibody produced in response to an infection and is mainly involved in the primary immune response. IgA is predominantly found in mucosal areas and secretions, providing localized protection but is not directly involved in allergic responses.