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Table 1 Environmental and clinical associations of autoantibody subgroups

From: Adult and juvenile dermatomyositis: are the distinct clinical features explained by our current understanding of serological subgroups and pathogenic mechanisms?

Myositis-specific autoantibodya Antibody target Environmental/genetic associations Frequency in juvenile IIM (%) Juvenile disease features Frequency in adult IIM (%) Adult disease features
Jo1, PL-7, PL-12, EJ, OJ, KS, Ha, Zo [39] tRNA synthetases: catalyse amino acid binding to their cognate RNAs [39] Onset in spring [74, 75] 1-5 [43, 44] Rare [40, 41] 40 [39] Anti-synthetase syndrome [39, 41]
Mi2 Nucleosome remodelling deacetylase complex (NuRD) [39] UV light exposure [76] 4-10 [39, 43, 46] Classic DM, mild disease [43, 46] 20 [39, 45] Classic DM, mild disease [39]
P155 - TIF1γ/TRIMM33 (transcriptional intermediary factor 1) Nuclear factor: acts as ubiquitin ligase for SMAD4. SMAD4 contributes to TGFβ signalling, suppressing cell growth [68] Juvenile disease trend towards late winter birth [77] 23 [50] Severe cutaneous disease [50] 13-21 [47] Severe cutaneous disease.
Malignancy in 50% [48, 49]
P140 - NXP2/MJ (nuclear matrix protein 2) Nuclear transcriprion factor involved in activation and localisation of tumour suppressor gene p53 [69] In adults high prevalence found in Italian cohort [55] 11-23 (personal data, [52, 53] Severe disease. Calcinosis [52, 53] 1.6-30 [50, 51] Rare in most adult populations
Possibly malignancy
Possibly calcinosis [54, 55]
P140 - MDA5 (melanoma differentiation associated gene 5) Cyoplasmic RNA helicase involved in inate immunity viral infection response [56] Increased prevalence in Eastern Asia. Rising frequency in central Japan [5658, 78] 7 (personal data) RP-ILD - in Japanese cohort Ulceration [62] 13-35 [56, 58] Amyopathic DM Characteristic cutaneous findings, ulceration RP-ILD [56, 58]
SAE (sumo-activating enzyme) Involved in post-transcriptional modification [39, 63]   <1% (personal data) Very rare 8.4 [63] Initially amyopathic disease
Dysphagia [63]
SRP (signal recognition peptide) Cytoplasmic protein involved protein recognition and translocation [39] Onset in autumn [74, 75]   Rare [43, 44, 66] 5 [39] Necrotising myopathy [64, 65]
  1. aJo1, histydly tRNA synthetase; PL-7, threonyl tRNA synthetase; Pl-12, alanyl tRNA synthetase; EJ, glycl tRNA synthetase; OJ, isoleucyl tRNA synthetase; KS, asparaginyl tRNA synthetase; Ha, tyrosyl tRNA synthetase; Zo, phenylalanyl tRNA synthetase. DM, dermatomyositis; IIM, idiopathic inflammatory myopathy; RP-ILD, rapidly progressive interstitial lung disease; TGF, transforming growth factor.