Anti–Melanoma Differentiation–Associated Gene 5 (MDA-5) Antibody and Dermatomyositis

Autoantibodies have been routinely detected in patients with inflammatory myopathies, including dermatomyositis. Antibodies directed against melanoma differentiation–associated gene 5 (MDA-5) protein have been linked to amyopathic dermatomyositis and rapidly progressive interstitial lung disease (ILD) in Asian, particularly Japanese, patients. It has not been clear whether the association is generalizable to patients seen in the U.S. or if testing for these antibodies has clinical utility.

Two reports, from the U.S. and China, of patients with anti–MDA-5 autoantibodies recently appeared in the rheumatology literature. The first, from the Johns Hopkins myositis referral center, retrospectively compared patients with and without MDA-5 antibodi…