We analyzed sera from five JDM patients, each with three MSAs (anti-melanoma differentiation-associated protein 5 antibodies; anti-MDA5, anti-nuclear matrix protein 2 antibodies; anti-NXP2, or anti-transcriptional intermediary factor 1 alpha and/or gamma subunits antibodies; anti-TIF-1γ) and five healthy controls by single-shot LC-MS/MS in data-independent acquisition (DIA) mode to construct protein profiles associated with clinical symptoms and MSAs.