Antimicrosomal antibody

Antimicrosomal antibody is a type of autoantibody that is often present in the blood of individuals with certain autoimmune diseases, particularly Hashimoto's thyroiditis and Graves' disease. These antibodies are directed against certain proteins found in the thyroid gland, specifically those located in the thyroid microsomes.

Overview

Antimicrosomal antibodies, also known as thyroid peroxidase antibodies (TPOAb), are produced by the body's immune system when it mistakenly identifies thyroid microsomes as foreign substances. The presence of these antibodies can lead to inflammation and damage to the thyroid gland, resulting in conditions such as Hashimoto's thyroiditis and Graves' disease.

Clinical Significance

Testing for antimicrosomal antibodies is often performed as part of the diagnostic process for suspected thyroid disorders. Elevated levels of these antibodies can indicate an autoimmune thyroid disease. However, they can also be present in individuals without any apparent thyroid disease, particularly in older women.

Hashimoto's Thyroiditis

In Hashimoto's thyroiditis, the most common cause of hypothyroidism, the immune system attacks the thyroid gland, leading to inflammation and impaired thyroid function. Antimicrosomal antibodies are found in approximately 90-95% of individuals with this condition.

Graves' Disease

Graves' disease, the most common cause of hyperthyroidism, is another autoimmune condition in which the thyroid gland is attacked by the immune system. While antimicrosomal antibodies are less commonly found in individuals with Graves' disease compared to Hashimoto's thyroiditis, they are still present in approximately 75% of cases.

See Also

• Autoimmune disease
• Thyroid disease
• Hashimoto's thyroiditis
• Graves' disease