Pathology Features of Immune and Inflammatory Myopathies, Including a Polymyositis Pattern, Relate Strongly to Serum Autoantibodies

J Neuropathol Exp Neurol. 2021 Sep 27;80(9):812-820. doi: 10.1093/jnen/nlab071.


We asked whether myopathology features of immune or inflammatory myopathies (IIM), without reference to clinical or laboratory attributes, correlate with serum autoantibodies. Retrospective study included 148 muscle biopsies with: B-cell inflammatory foci (BIM), myovasculopathy, perimysial pathology (IMPP), myofiber necrosis without perimysial or vessel damage or inflammation (MNec), inflammation and myofiber vacuoles or mitochondrial pathology (IM-VAMP), granulomas, chronic graft-versus-host disease, or none of these criteria. 18 IIM-related serum autoantibodies were tested. Strong associations between myopathology and autoantibodies included: BIM with PM/Scl-100 (63%; odds ratio [OR] = 72); myovasculopathies with TIF1-γ or NXP2 (70%; OR = 72); IMPP with Jo-1 (33%; OR = 28); MNec with SRP54 (23%; OR = 37); IM-VAMP with NT5C1a (95%; OR = 83). Hydroxymethylglutaryl-CoA reductase (HMGCR) antibodies related to presence of myofiber necrosis across all groups (82%; OR = 9), but not to one IIM pathology group. Our results validate characterizations of IIM by myopathology features, showing strong associations with some serum autoantibodies, another objective IIM-related marker. BIM with PM/Scl-100 antibodies can be described pathologically as polymyositis. Tif1-γ and NXP2 antibodies are both common in myovasculopathies. HMGCR antibodies associate with myofiber necrosis, but not one IIM pathology subtype. Relative association strengths of IIM-related autoantibodies to IIM myopathology features versus clinical characteristics require further study.

Keywords: Autoantibodies; B-cells; Immune; Inflammatory; Myopathy; Myositis; Necrosis.

MeSH terms

  • Autoantibodies / blood*
  • Autoantibodies / immunology
  • B-Lymphocytes / immunology
  • Graft vs Host Disease / immunology*
  • Humans
  • Hydroxymethylglutaryl CoA Reductases / immunology
  • Inflammation / immunology*
  • Inflammation / pathology
  • Myositis / immunology
  • Myositis / pathology*
  • Necrosis / immunology
  • Polymyositis / immunology
  • Polymyositis / pathology*
  • Signal Recognition Particle / immunology


  • Autoantibodies
  • Signal Recognition Particle
  • Hydroxymethylglutaryl CoA Reductases