Dilated cardiomyopathy caused by coxsackievirus B myocarditis involves molecular mimicry. The cardiac autoantigen mimicked by the viral capsid protein is:

• A Desmin intermediate filament (cytoskeletal protein)
• B Cardiac troponin I (contractile regulatory protein)
• C Alpha-actinin (sarcomeric Z-disc protein)
• D Cardiac beta-myosin heavy chain and adenine nucleotide translocator ✓

Explanation

In coxsackievirus B myocarditis, the viral VP1 capsid protein shares epitopes with cardiac beta-myosin heavy chain and the adenine nucleotide translocator (ANT). Immunological cross-reactivity causes T-cell and antibody-mediated autoimmune destruction of cardiomyocytes even after viral clearance, contributing to dilated cardiomyopathy. Anti-heart autoantibodies against these proteins are detected in patients with post-myocarditis DCM. Desmin mutations cause familial DCM but are not a target of viral molecular mimicry. Troponin I is a biomarker released in cardiomyocyte necrosis, not an autoantigen in this context.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.