Fig. 3

Role of hypoxia and IFN1-associated molecules in perifascicular regions of skeletal muscle biopsies derived from jDM and aDM patients. CD56⁺ myofibers are more prominent and more widespread in the perifascicular region in jDM (a) compared to aDM (b). Neonatal myosin + myofibers (green) frequently co-stain with VEGF⁺ (red) myofibers in jDM (c), and only occasional double positive fibers are detected in aDM samples (d; original magnification x200). Numerous HIF1a⁺ myofibers are detected in the perifascicular region in jDM (e), while this is not the case in aDM (f). Using a different clone highlights double positive HIF1a⁺ (red) and CD206⁺ macrophages (green) in jDM (g), but CD206⁺ macrophages do not co-label with HIF1a in aDM (h). ISG15 (red) is co-expressed in a few perifascicular atrophic neonatal myosin⁺ myofibers (green) in jDM (i), but ISG15 is much more widespread and strongly stains multiple layers of the perifascicular regions in aDM and co-stains with neonatal myosin (k)