[Myositis-specific autoantibodies].
BACKGROUND
Myositis-specific antibodies (MSA) are autoantibodies that are almost exclusively detected in idiopathic inflammatory myopathies (IIM). This article provides an overview of these autoantibodies and how they can be used clinically to identify subgroups of IIM.


METHODS
The article is based on a non-systematic literature review and our own experience.


RESULTS
MSA can be detected in up to 50 % of patients with IIM. Patients with anti-synthetase antibodies have a constellation of clinical findings termed "the anti-synthetase syndrome", in which interstitial lung disease dominates the clinical picture. Anti-Mi2 antibodies is another myositis-specific antibody. Patients with anti-Mi2 antibodies often have classical dermatomyositis, while the anti-SRP antibody identifies patients with severe myopathy, poor response to treatment with corticosteroids and histological findings of muscle cell necrosis - often lacking inflammatory infiltrates. The newly detected anti-CADMp140 appears to be associated with amyopathic or hypomyopathic dermatomyositis, previously called dermatomyositis sine myositis. Anti-p155 antibodies are most often found in patients who also have cancer.


CONCLUSIONS
Myositis-specific antibodies may be useful for identification of clinical subgroups of IIM and can thereby affect the choice of medical treatment.
Gran
Jan Tore
JT
Revmatologisk avdeling, Oslo universitetssykehus, Rikshospitalet, 0027 Oslo, Norway. jan.tore.gran@rikshospitalet.no
Molberg
Øyvind
Ø
Dobloug
Gerd Cecilie
GC
Andersson
Helena
H
Taraldsrud
Eli
E
Scheie
David
D
D000604:Amino Acyl-tRNA Synthetases / Q000276:immunology; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001323:Autoantibodies / Q000032:analysis*; D003882:Dermatomyositis / Q000276:immunology; D018450:Disease Progression; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D036341:Intercellular Signaling Peptides and Proteins; D009220:Myositis / Q000145:classification / Q000188:drug therapy / Q000276:immunology*; D009687:Nuclear Proteins / Q000276:immunology; D010455:Peptides / Q000276:immunology; D018271:Signal Recognition Particle / Q000276:immunology
D000893:Anti-Inflammatory Agents; D001323:Autoantibodies; C501597:CADM-140 peptide, human; D007166:Immunosuppressive Agents; D036341:Intercellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D010455:Peptides; D018271:Signal Recognition Particle; D000604:Amino Acyl-tRNA Synthetases