American Board of Internal Medicine (ABIM) Certification Practice Exam

What type of antibodies are typically produced in autoimmune thyroiditis?

1. Anti-histone

2. Anti-microsomal

3. Anti-desmoglein

4. Anti-Jo-1

The correct answer is: Anti-microsomal

In autoimmune thyroiditis, specifically Hashimoto's thyroiditis, the immune system produces specific antibodies that target components of the thyroid gland. The most notable antibodies associated with this condition are anti-thyroid peroxidase antibodies, also known as anti-microsomal antibodies. These antibodies are directed against thyroid peroxidase, an enzyme crucial for the synthesis of thyroid hormones. While anti-histone antibodies are typically linked with drug-induced lupus erythematosus, anti-desmoglein antibodies are associated with pemphigus vulgaris, and anti-Jo-1 antibodies are found in polymyositis and dermatomyositis, none of these are relevant to autoimmune thyroiditis. The presence of anti-microsomal antibodies is a hallmark feature in the diagnosis of autoimmune thyroid disorders, making the identification of these antibodies critical in understanding and diagnosing conditions like Hashimoto's thyroiditis.