Fig. 4

Analysis of immunoglobulin expression and autoimmune markers in inherited and sporadic late-onset nemaline myopathies (A) Proteomic analysis showed an increased abundance of IgG heavy chains and both kappa and lambda light chains in nemaline rod areas in sporadic late-onset nemaline myopathy (SLONM) relative to inherited nemaline myopathies (iNM). There was also a trend towards an increased abundance of immunoglobulin chains in the nemaline rod areas of SLONM relative to rod-free areas. Striped bars indicate immunoglobulin chains that were only detected in one of the groups of samples compared *p < 0.05. (B) Immunofluorescent staining demonstrated accumulation of kappa light chains in atrophic fibers in 38% of SLONM biopsies (bottom row), but not in iNM (top row). Scale bar = 400 µm. (C) Immunoglobulin genes were also differentially expressed between SLONM and iNM. (D) Immunostaining for Major Histocompatibility Antigen-I (MHC-I) showed reactivity in SLONM biopsies, occurring predominantly in atrophic fibers (first panel, SLONM with monoclonal gammopathy; second panel, SLONM without monoclonal gammopathy). Biopsies from patients with inherited nemaline myopathy showed no MHC-I reactivity or occasional fibers faintly reactive for MHC-I (third panel, adult patient with ACTA1 nemaline myopathy). MHC-I reactivity was absent in healthy control muscle (fourth panel). Scale bar = 100 µm