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Table 1 Summary of the main features of MSAs and MAAs

From: Bench to bedside review of myositis autoantibodies

Antibody Antigen IP IIF Clinical association
Proteins (kDa) RNA HEp-2
Myositis-specific autoantibodies (MSAs)
 Anti-Jo-1 Histidyl-tRNA synthetase 50 tRNAHis Cytoplasmic fine speckled Classic anti-synthetase syndrome with more frequent muscle involvement
 Anti-PL-7 Threonyl-tRNA synthetase 80 tRNAThr Cytoplasmic dense fine speckled Anti-synthetase syndrome with prevalent ILD
 Anti-PL-12 Alanyl-tRNA synthetase 110 tRNAAla Cytoplasmic dense fine speckled Anti-synthetase syndrome with prevalent ILD
 Anti-EJ Glycyl-tRNA synthetase 75 tRNAGly Cytoplasmic speckled Anti-synthetase syndrome
 Anti-OJ Isoleucyl-tRNA synthetase 150 + 170/130/75 tRNAIso Cytoplasmic speckled ILD alone or anti-synthetase syndrome
 Anti-KS Asparaginyl-tRNA synthetase 65 tRNAAsp Cytoplasmic speckled ILD alone or anti-synthetase syndrome
 Anti-Zo Phenylalanyl-tRNA synthetase 60/70 tRNAPhe Cytoplasmic speckled Myositis
 Anti-YRS/HA Tyrosyl-tRNA synthetase 59 tRNATyr Cytoplasmic speckled Myositis
 Anti-Mi-2 Nucleosome Remodelling Deacetylase (NuRD) (Mi-2α/β) 240 + 200/150/75/65/63/50/34   Fine speckled Classical DM
 Anti-SAE Small ubiquitin-like modifier activating enzyme (SAE1/2) 40/90   Fine speckled Severe cutaneous disease that classically precede DM with severe dysphagia and systemic symptoms
 Anti-MDA5 (anti-CADM140) Melanoma Differentiation-Associated gene 5 (MDA5) 140   Negative or Cytoplasmic speckled Hypo-amyopathic, ILD with possible RP-ILD and severe and peculiar skin involvement
 Anti-TIF1γ/α (anti-p155/p140) Transcription intermediary factor 1 (TIF1γ/α) 155/140   Fine speckled Juvenile DM. Cancer-associated hypo-myopathic DM
Anti-TIF1β Transcription intermediary factor 1β 120   Fine speckled DM
 Anti-NXP2 (anti-MJ) Nuclear matrix protein (NXP-2) 140   Fine speckled and/or multiple nuclear dots Juvenile DM, diffused calcinosis. Cancer-associated DM
 Anti-SRP Signal recognition particle 72/68/54/19/14/9 7SL Cytoplasmic dense fine speckled IMNM with frequent esophageal involvement. Possible ILD
 Anti-HMGCR HMG-CoA reductase 200/100   Negative or Cytoplasmic speckled IMNM with or without history of statin exposure
Myositis-associated autoantibodies(MAAs)
 Anti-PM-Scl Exosome protein complex (PM/Scl75/100) 75/100   Nucleolar homogeneous Overlap PM/SSc
 Anti-C1D Exosome associated protein     Overlap PM/SSc
 Anti-U1-RNP U1 small nuclear RNP 11–70 U1 Coarse speckled MCTD
 Anti-fibrillarin (anti-U3-snRNP) Fibrillarin 34 U3 Nucleolar clumpy SSc
 Anti-Ku DNA-PK regulatory subunit 70/80   Fine speckled PM/SSc. Potentially severe ILD
 Anti-Ro52 Ro-52/TRIM21 52   Negative, fine speckled or cytoplasmic speckled ILD. Frequently coupled with other MSA
 Anti-Ro60/SSA Ro-60/SS-A 60   Fine speckled SjS, SLE
 Anti-La/SSB SS-B 48   Fine speckled SjS, SLE
 Anti-cN-1A (anti-Mup44) Cytosolic 5′nucleotidase 1A     sIBM
 Anti-RuvBL1/2 RuvBL1/2 complex 48/49   Speckled SSc, PM, Morphea
 Anti-Su/Ago2 Argonaute 2 100/102 and 200   Cytoplasmic discrete dots ILD in absence of cancer. Frequently coupled with MSA, Ro-52 and other antibodies
 Anti-SMN Survival of Motor Neuron 38 + 130/120/33   Few nuclear dots PM/SSc
 Anti-NUP Nup358/RanBP2, gp210, Nup90, p200/p130, Nup62    Punctate nuclear envelope Subgroup of PM/SSc patients (so called NUP-syndrome). PBC
 Anti-mitochondrial (AMA-M2) Branched-chain α-ketoacid dehydrogenase complex    Cytoplasmic reticular/AMA Long-lasting myositis with muscle atrophy and cardiac involvement. PBC
 Anti-KJ Translocation factor 30/43   Cytoplasmic speckled Anti-synthetase-like syndrome
 Anti-Fer (anti-eEF1) Eukaryotic elongation factor 1     Anti-synthetase-like syndrome
 Anti-Wa   48   Cytoplasmic speckled Anti-synthetase-like syndrome
 Anti-Mas selenocysteine seryl-tRNA-protein complex 48 tRNA[Ser]Sec Cytoplasmic speckled Non-immune mediated rhabdomyolysis. Autoimmune hepatitis
 Anti-PMS DNA repair mismatch enzyme (PMS1, PMS2, MLH1)     Mild myositis
 Anti-cortactin Cortactin 68    PM. Myasthenia gravis
 Anti-FHL1 Four-and-a-Half LIM domain 1     Myositis and muscular atrophy with severe systemic involvement