Advanced Oncology Certified Nurse Practitioner (AOCNP) Certification Practice Test

Anaphylactic reactions are characterized by the involvement of which immunoglobulin?

1. Immunoglobulin A (IgA)

2. Immunoglobulin M (IgM)

3. Immunoglobulin G (IgG)

4. Immunoglobulin E (IgE)

The correct answer is: Immunoglobulin E (IgE)

Anaphylactic reactions are primarily mediated by Immunoglobulin E (IgE). This immunoglobulin plays a crucial role in the body's allergic response. When an individual is exposed to an allergen, IgE antibodies bind to surface receptors on mast cells and basophils, which are types of immune cells. Upon re-exposure to the same allergen, these cells can rapidly degranulate, releasing a variety of chemicals, including histamine, which leads to the symptoms associated with anaphylaxis, such as difficulty breathing, swelling, hives, and a drop in blood pressure. The other immunoglobulins listed serve different functions within the immune system. For instance, IgA is primarily involved in mucosal immunity and protection at epithelial surfaces, IgM is the first antibody produced in response to an infection and is effective in the early stages of an immune response, while IgG is the most abundant antibody in circulation, crucial for opsonization and neutralization of pathogens but not directly linked to the immediate hypersensitivity response in anaphylaxis.