[Dermatomyositis and polymyositis].
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.
Pellissier
J F
JF
Laboratoire de Biopathologie Nerveuse et Musculaire, EA 3281, Faculté de Médecine de Marseille, France. Jean-Francois.Pellissier@medecine.univ-mrs.fr
Civatte
M
M
Fernandez
C
C
Bartoli
C
C
Chetaille
B
B
Schleinitz
N
N
Figarella-Branger
D
D
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*
D015415:Biomarkers