title: Myeloid dendritic cells in inclusion-body myositis and polymyositis.
abstract: Dendritic cells (DCs), immune system cells central to the development of immunity, have not previously been reported in muscle in inclusion-body myositis (IBM). We performed immunohistochemical studies on muscle biopsy specimens from 50 patients using monoclonal antibodies that distinguish two classes of DCs, myeloid DC and plasmacytoid DC. In 17 of 20 IBM and 9 of 10 polymyositis (PM) specimens, myeloid DCs were present in substantial numbers, frequently surrounded and sometimes invading otherwise intact myofibers, and were part of dense collections of cells that included T cells. Dermatomyositis muscle had more plasmacytoid DCs than myeloid DCs, whereas IBM and PM had greater numbers of myeloid DCs. The stellate morphology of myeloid DCs in dense collections of cells that included T cells suggests local intramuscular antigen presentation in IBM and PM.
authors.affiliation: Department of Neurology, Division of Neuromuscular Disease, Brigham and Women's Hospital, 75 Francis Street, and Harvard Medical School, Boston, Massachusetts 02115, USA. sgreenberg@partners.org
authors.forename: Steven A
authors.initials: SA
authors.lastname: Greenberg
authors.forename: Geraldine S
authors.initials: GS
authors.lastname: Pinkus
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Amato
authors.forename: Jack L
authors.initials: JL
authors.lastname: Pinkus
mesh_terms: D000911:Antibodies, Monoclonal; D017951:Antigen Presentation / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D019070:Cell Lineage / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D019204:GTP-Binding Proteins / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D016898:Interferon-alpha / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016899:Interferon-beta / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D037181:Lectins, C-Type / Q000276:immunology / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism; D018482:Muscle, Skeletal / Q000276:immunology / Q000473:pathology*; D022423:Myeloid Cells / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D018979:Myositis, Inclusion Body / Q000276:immunology / Q000473:pathology*; D064547:Myxovirus Resistance Proteins; D010950:Plasma Cells / Q000276:immunology / Q000473:pathology; D017285:Polymyositis / Q000276:immunology / Q000473:pathology*; D011971:Receptors, Immunologic / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology; D015533:Transcriptional Activation / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D015415:Biomarkers; C443299:CLEC4C protein, human; D016898:Interferon-alpha; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D064547:Myxovirus Resistance Proteins; D011971:Receptors, Immunologic; D016899:Interferon-beta; D019204:GTP-Binding Proteins