The composition of cellular infiltrates in anti-HMG-CoA reductase-associated myopathy

Muscle Nerve. 2015 Aug;52(2):189-95. doi: 10.1002/mus.24642. Epub 2015 May 14.


Introduction: To characterize cellular infiltrates in muscle biopsies from patients with anti-3-hydroxy-3-methyl-gulatryl-CoA reductase (HMGCR)-associated myopathy.

Methods: Biopsies from 18 anti-HMGCR myopathy and 7 control dermatomyositis patients were analyzed.

Results: CD4+ and CD8+ T-cells were scattered within the endomysium in 50% of anti-HMGCR biopsies. All anti-HMGCR biopsies included increased endomysial and/or perivascular CD163+ M2 macrophages; CD11c+ M1 macrophages were present in 18.8%. CD123+ plasmacytoid dendritic (PD) cells were observed within the endomysium and perivascular spaces in 62.5% of anti-HMGCR biopsies. Membrane attack complex was deposited on endothelial cells in 50% and on the sarcolemma of nonnecrotic muscle fibers in 85.7% of anti-HMGCR cases. Major histocompatibility complex class I antigen was up-regulated in 87.5% of the anti-HMGCR cases.

Conclusions: In addition to necrosis, scattered CD4+, CD8+, and PD cells are characteristic of anti-HMGCR myopathy. Predominant M2 polarization suggests infiltrating macrophages are more likely to be involved with tissue repair than destruction.

Keywords: anti-HMGCR myopathy; autoimmune myopathy; immune-mediated necrotizing myopathy; muscle histology; myositis.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD4-Positive T-Lymphocytes / enzymology
  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / pathology
  • CD8-Positive T-Lymphocytes / enzymology
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / pathology
  • Dendritic Cells / enzymology
  • Dendritic Cells / immunology*
  • Dendritic Cells / pathology
  • Female
  • Humans
  • Hydroxymethylglutaryl CoA Reductases / immunology*
  • Hydroxymethylglutaryl CoA Reductases / metabolism
  • Male
  • Middle Aged
  • Muscular Diseases / diagnosis*
  • Muscular Diseases / enzymology
  • Muscular Diseases / immunology*


  • HMGCR protein, human
  • Hydroxymethylglutaryl CoA Reductases