The composition of cellular infiltrates in anti-HMG-CoA reductase-associated myopathy.
BACKGROUND
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.
Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Tae
T
Chung
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Lisa
L
Christopher-Stine
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Julie J
JJ
Paik
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Andrea
A
Corse
Muscle Disease Unit, Laboratory of Muscle Stem Cells and Gene Expression, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, 50 South Drive, Room 1146, Building 50, MSC 8024, Bethesda, Maryland, 20892, USA.
Andrew L
AL
Mammen
D015496:CD4-Positive T-Lymphocytes / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D003713:Dendritic Cells / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D005260:Female; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009135:Muscular Diseases / Q000175:diagnosis* / Q000201:enzymology / Q000276:immunology*
C553220:HMGCR protein, human; D006903:Hydroxymethylglutaryl CoA Reductases
anti-HMGCR myopathy; autoimmune myopathy; immune-mediated necrotizing myopathy; muscle histology; myositis