IFIH1 and dermatomyositis: Anti-MDA5 antibodies are relatively common in DM patients, accounting for approximately 1% to 30% of DM, which is slightly lower than our data.[19] More than half of anti-MDA5 antibody-positive patients develop ILD, including rapidly progressive ILD, a subtype that can lead rapidly progressive respiratory deterioration with a very high mortality rate.[20] Compared with other types of antibodies, anti-MDA5 antibody-positive patients developed skin or oral ulcers, mechanic’s hands, arthralgia and fever more frequently.