ISG15 and dermatomyositis: Microarray studies of muscle biopsies from patients with DM have shown overexpression of IFN-I-inducible transcripts, such as interferon-inducible protein 15 (ISG15), Myxovirus resistance A (MxA), Signal Transducer and Activator of Transcription 1 (STAT1) and retinoic acid-inducible gene I (RIG-I), that were validated at the protein level and specifically detected at perifascicular atrophic areas in DM muscle10–14.