Which of the following illnesses is an example of a type III hypersensitivity reaction?

Which of the following illnesses is an example of a type III hypersensitivity reaction?
A . Lupus
B . Graves disease
C . Hashiomoto’s thyroiditis
D . Allergic rhinitis
E . Myasthenia gravis

View Answer

Answer: A

Explanation:

A type III hypersensitivity reaction is mediated by immune complex deposition. In lupus, auto-antibodies are formed and these complexes are deposited in other tissues, especially in the kidneys, skin, and joints. Graves disease and myasthenia gravis are examples of type II but in some classification systems they are called type V reactions. The auto-antibodies created in Graves attack TSH receptors in the thyroid, whereas in Myasthenia the target is the acetylcholine receptor. Hashimoto’s thyroiditis is usually considered an example of a combination of type II and IV reactions, as T cells are directed at thyroid antigens and antibodies are also produced. Allergic rhinitis is a classic example of a type I, IgE mediated reaction.