Which of the following parts of the immune system plays a role in the allergic cascade?

A.         Mast cells

B.            Basophils

C.        Histamine

D.            Immunoglobulin E (IgE)

E.         All of the above

The correct answer is (E) All of the above.

The allergic cascade is the sequence of chemical releases that takes place in the body in response to an allergen. IgE is a specific type of antibody that attaches to mast cells and basophils, which are types of white blood cells. When an allergen is encountered by the immune system, the IgE triggers mast cells and basophils into releasing histamines. Histamines are a type of "chemical mediator" that tells other cells how to behave. It is the histamines that are responsible for directly causing allergy symptoms ranging from congestion to a drop in blood pressure and anaphylactic shock.