title: [Dermatomyositis and polymyositis].
abstract: Dermatomyositis (DM) and polymyositis (PM) are the two main forms of idiopathic inflammatory myopathies. They have in common a proximal muscle weakness, but skin manifestations, juvenile forms and increased incidence of malignancies are clinical characteristics of DM. The follow up of creatine-kinases is the best biological test in spite of their possible normality. The significance of antibodies titers is uncertain, except the association Jo-1 interstitial and lung disease indicating a poor prognosis. The association with HLA haplotypes expresses a genetic predisposition of a dysimmunity to develop DM or PM. Pathological changes are well known with a humoral immune effector mechanism in DM, and a muscle fibre aggression by CD8 + T cells in PM. Non inflammatory forms of DM and PM and rhabdomyolytic forms of PM are not very rare, they are recognized by the HLA class 1 immunoreactivity. Pathophysiological processes involve muscle fibers, inflammatory cells and endothelial cells of capillaries, with a complex intervention of cytokines, adhesion molecules, MHC classe 1, membrane attack complex, anti endothelial cells antibodies, perforin secretion and sometimes apoptotic Fas-mediated mechanisms. Despite these recent advances, causal antigens and activator processes of endothelial cell lysis and autoinvasive cytotoxicity of muscle fibers remain to be identified.
authors.affiliation: Laboratoire de Biopathologie Nerveuse et Musculaire, EA 3281, Faculté de Médecine de Marseille, France. Jean-Francois.Pellissier@medecine.univ-mrs.fr
authors.forename: J F
authors.initials: JF
authors.lastname: Pellissier
authors.forename: M
authors.initials: M
authors.lastname: Civatte
authors.forename: C
authors.initials: C
authors.lastname: Fernandez
authors.forename: C
authors.initials: C
authors.lastname: Bartoli
authors.forename: B
authors.initials: B
authors.lastname: Chetaille
authors.forename: N
authors.initials: N
authors.lastname: Schleinitz
authors.forename: D
authors.initials: D
authors.lastname: Figarella-Branger
mesh_terms: D015415:Biomarkers; D003882:Dermatomyositis / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D018450:Disease Progression; D004594:Electrophysiology; D006801:Humans; D017285:Polymyositis / Q000235:genetics / Q000276:immunology / Q000473:pathology*
chemical_list: D015415:Biomarkers