Supplementary Figure 1.

Control stainings. (A–F) Staining for myogenic regulatory factors and corresponding IgG1 isotype controls on consecutive sections in a case with LGMD 2B (dysferlinopathy). (A) Pax7⁺ satellite cells attached to a muscle fiber (arrows; in (D) same fiber on the consecutive section exposed to IgG1 isotype control). (B) Mononuclear myogenic cells expressing MyoD (arrows). (C) Regenerating muscle fibers with Myogenin⁺ nuclei (arrows). (E and F) Corresponding IgG1 isotype controls on consecutive sections. (G–I) Muscle from a control individual without myopathy yielding few Pax7⁺ satellite cells (G, arrows) and a single Myogenin⁺ cell (H, arrow), while MyoD is not expressed (I). (A–F) original magnification 63×; (G–I) OM 40×. (J) Double-immunoflourescence stain for TDP-43 (green sarcoplasmic deposits indicated by arrows) and NCAM (red) in sIBM. (K) Consecutive section exposed to total IgG from rabbit serum instead of anti-TDP-43 antibody (both used at a concentration of 45 μg/150 ml) and NCAM excluding non-specific binding of the polyclonal antibody. (L) NCAM⁺ fibers in PM are negative for TDP-43 (double-immunoflourescence for TDP-43 and NCAM, Dapi for nuclei, OM 63×). (M) Anti-CD34 stain showing endothelial cells of capillaries and a CD34⁺ mononuclear cell (arrow) in case with PM. (N) Double stain for CD34 and laminin demonstrates the interstitial position of the CD34⁺ mononuclear cell, while capillaries are surrounded by a laminin⁺ basement membrane (double-immunoflourescence for CD34 and laminin, Dapi for nuclei, OM 63×). (O) Consecutive section exposed to IgG isotype control (Dapi for nuclei, OM 63×).