Amyopathic dermatomyositis developing rapidly progressive interstitial lung disease with elevation of anti-CADM-140/MDA5 autoantibodies.

Anti-clinically amyopathic dermatomyositis (CADM)-140/MDA5 autoantibodies are specifically detected in patients with dermatomyositis and are known to have a strong association with rapidly progressive interstitial lung disease (RP-ILD). Here we report an amyopathic dermatomyositis (ADM) patient who developed RP-ILD characterized by elevated anti-CADM-140/MDA5 titer. Respiratory symptoms gradually improved, and anti-CADM-140/MDA5 titer decreased in parallel to below the cutoff level. It may be useful to quantify CADM-140-specific autoantibodies for monitoring disease activity in patients with ADM and RP-ILD.