title: [Pathogenesis of primary inflammatory myopathies].
abstract: COMMON ELEMENTS: Primary inflammatory myopathies consist of dermatomyositis (DM), polymyositis (PM) and inclusion body myositis (IBM). They have certain characteristics in common: progressive muscle weakness and mononuclear inflammatory infiltrates in the muscle. DIFFERENT MECHANISMS: They may be distinguished by their histological features which also reflect their different underlying pathogeneses. The mechanism of DM would be complement-mediated microangiopathy, the inflammatory infiltrate of which would be secondary to ischemic phenomena, whereas in PM the muscle fibres are damaged by cytotoxic CD8 T lymphocytes. The factors triggering-off these two forms of myositis remain unknown. IBM may be a degenerative disease with accumulation of a variety of proteins within the fibres. The inflammatory infiltrate, which is similar to that seen in PM, may be a reaction to accumulated proteins.
authors.affiliation: Service de médecine interne 1, Groupe hospitalier Pitié-Salpêtrière, 47-83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France. olivier.benveniste@psl.ap-hop-paris.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Benveniste
authors.forename: Waney
authors.initials: W
authors.lastname: Squier
authors.forename: Olivier
authors.initials: O
authors.lastname: Boyer
authors.forename: David
authors.initials: D
authors.lastname: Hilton-Jones
authors.forename: Serge
authors.initials: S
authors.lastname: Herson
mesh_terms: D016827:CD8 Antigens / Q000276:immunology; D003882:Dermatomyositis / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D018482:Muscle, Skeletal / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D009220:Myositis / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D018979:Myositis, Inclusion Body / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D017285:Polymyositis / Q000276:immunology / Q000473:pathology / Q000503:physiopathology
chemical_list: D016827:CD8 Antigens