American Board of Internal Medicine (ABIM) Certification Practice Exam

Which autoantibody is associated with pemphigus vulgaris?

1. Anti-microsomal

2. Anti-desmoglein

3. Anti-parietal cell

4. Anti-histone

The correct answer is: Anti-desmoglein

Pemphigus vulgaris is a serious autoimmune blistering disorder characterized by the presence of autoantibodies that target proteins in the skin. The key autoantibodies involved in this condition are the anti-desmoglein antibodies. Desmogleins are components of desmosomes, which are structures that provide adhesion between keratinocytes in the epidermis. In pemphigus vulgaris, autoantibody binding to desmogleins leads to the disruption of cell adhesion, causing the characteristic blistering and erosions seen in this disease. The other autoantibodies listed do not play a role in pemphigus vulgaris. For example, anti-microsomal antibodies are often associated with autoimmune thyroid diseases, while anti-parietal cell antibodies are linked to autoimmune gastritis. Anti-histone antibodies are typically associated with drug-induced lupus erythematosus. Thus, the presence of anti-desmoglein antibodies specifically aligns with the pathophysiology of pemphigus vulgaris, confirming its role as a hallmark of the disease.