IFIH1 and dermatomyositis: In order to discover metabolite biomarkers for predicting MDA5 + DM patients, we also divided DM patients into discovery (MDA5 + , n = 12; MDA5-, n = 19) and validation (MDA5 + , n = 5; MDA5-, n = 10) groups based on MDA5 positive or negative (Fig. 1a).