The characterization of circulating extracellular vesicles and small non-coding RNAs cargo in idiopathic inflammatory myopathies reveals differences across clinically diagnosed myositis subsets

Objective. To investigate the epigenetic footprint of idiopathic inflammatory myopathies (IIM) through characterization of circulating extracellular vesicles (EVs) and the expression of EV-derived small non-coding RNAs (sncRNAs). Overall design: In this cross-sectional study, EVs were isolated by size-exclusion chromatography from plasma of patients with IIM and matched healthy donors (HD). EV-derived sncRNAs were sequenced and quantified using Next-Generation Sequencing (NGS). Following quality control and normalization, filtered count reads were used for differential microRNAs (miRNAs) and piwi-interacting RNAs (piRNAs) expression analyses. Putative gene targets enriched for pathways implicated in IIM were analyzed. Patients' clinical and laboratory characteristics at the time of sampling were recorded.