Fig. 1

Histological analysis of jDM (a, c, e, g, i, l), and aDM (b, d, f, h, k, m) muscle biopsy specimens. Multiple layers of atrophic myofibers in perifascicular regions are illustrated both in jDM (a) and in aDM (b) by H&E and by MHCI staining in jDM (inlay a) as well as in aDM (inlay b). CD8⁺ lymphocytic infiltrates, are localized in the perimysium, and extend focally into the endomysium both in jDM and in aDM (c, d). CD68⁺ macrophages were identified both in jDM and in aDM (e, f). Close proximity between CD206⁺ macrophages (AEC, red) with laminin a5⁺ capillaries (DAB, brown) in the perifascicular region in jDM (g), which is less obvious in aDM (h). Capillary dropout is more evident in jDM as compared to aDM as illustrated by CD31 staining (i, k). COX-SDH enzymo-histochenmical preparations show severe pallor by COX staining giving rise to a greyish appearance in jDM (l), while the identical staining procedure done in parallel produced this aspect only in the perifascicular atrophic region in aDM patients (m). Arrows highlighting the respective features in photomicrographs