Paramedic National Registry Practice

Which immunoglobulin plays a critical role during an anaphylactic reaction?

1. IgA

2. IgG

3. IgM

4. IgE

The correct answer is: IgE

In the context of anaphylactic reactions, IgE is the immunoglobulin that plays a critical role. This type of immunoglobulin is primarily involved in allergic reactions and is essential in recognizing allergens. When an individual is exposed to a specific allergen for the first time, IgE antibodies are produced and bind to mast cells and basophils. Upon subsequent exposures to the same allergen, these IgE antibodies trigger the release of histamines and other chemicals from these cells, leading to the symptoms associated with anaphylaxis, such as swelling, difficulty breathing, and a drop in blood pressure. Other types of immunoglobulins, such as IgA, IgG, and IgM, are involved in different aspects of the immune response but do not have the same direct role during anaphylaxis. For example, IgA is primarily found in mucosal areas and body fluids; IgG is the most abundant antibody in circulation and provides long-term immunity; and IgM is the first antibody produced in response to an infection. However, none of these play the primary role that IgE does in mediating the rapid and severe reactions seen in anaphylaxis.