Auto-antibodies in dermatomyositis and polymyositis with corresponding clinical spectrum

AutoantibodiesAntibody targetFrequency in polymyositis/ADM/JDM %Frequency of ILD in adult/juvenile myositis %Clinical spectrum
In adulthoodIn childhood
Myositis-specific autoantibodies (MSA)
 Anti-tRNA synthetase29/20/5
  Anti-Jo1 (PL1)Histidyl-ARS21/11/<366/63Arthralgia, fever, RP, mechanic's hand, puffy fingerArthralgia, fever, RP, mechanic's hand, sclerodactyly
  Anti-YRS (Ha)Tyrosyl-ARS<1<1
 Dermatomyositis specific autoantibodies
  Anti-Mi2Nucleosome remodelling deacetylase complex1/9/4–104/0Classical DM without extramuscular involvementMild or moderate JDM
  Anti-NXP2 (MJ, p140)Nuclear matrix protein 210/0–3/12–250/25DM without extramuscular involvement, calcinosisMild or moderate JDM
  Anti-MDA5 (CADM-140)Melanoma differentiation-associated gene encoding RNA helicase<1/14–46/7Europe: 60; Asia: 90/Europe:19; Asia: 53Amyopathic DM, severe cutaneous ulcers, rapidly progressive ILDSevere cutaneous ulcers, RP-ILP, mediastinal emphysema
  Anti-TIF1γ (p155/140)Transcriptional intermediary factor 1γ<1/10–30/14–29<10/3Cancer associated DM in 78% of casesMild or moderate JDM
 Other MSA
  Anti-SRPSignal recognition particle5/1/<315/0Necrotising myopathySevere JPM
  Anti-HMGR (200–100)3-hydroxy-3-methylglutaryl-coenzyme A reductase10/<1/unknownUnknownNecrotising myopathyUnknown
  Anti-SAESmall ubiquitin-like modifier activating enzyme<1/5–10/1–9DMUnknown
Myositis-associated autoantibodies
 Anti-Ro/SsaRNP complexes with small cytoplasmic RNAs (hY-RNA)12/13/0
 Anti-U1RNP70 kDa, A and C polypeptides of U1 snRNP5/6/67DM, fever, RP, sclerodactyly
 Anti-PM/Scl (75 and 100 kDa)PM/Scl complex encompassing C1D, PM-Scl-100 and PM-Scl-75 proteins of the human exosome6/9/438Fever, RP, sclerodactyly
 Anti-Ku80 and 70 kDa DNA binding dimeric protein2/1/027Fever, RP, sclerodactyly
  • ADM: adult dermatomyositis; JDM: juvenile dermatomyositis; ILD: interstitial lung disease; SRP: signal recognition particle; ARS: aminoacyl-tRNA synthetase; RP: Raynaud's phenomenon; DM: dermatomyositis specific rash; RP-ILP: rapidly progressive ILD; JPM: juvenile polymyositis.