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] | 40 [39] | ||||
Mi2 | Nucleosome remodelling deacetylase complex (NuRD) [39] | UV light exposure [76] | 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. |
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] | Rare in most adult populations Possibly malignancy | |||
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 [56–58, 78] | 7 (personal data) | RP-ILD - in Japanese cohort Ulceration [62] | Amyopathic DM Characteristic cutaneous findings, ulceration RP-ILD [56, 58] | |
SAE (sumo-activating enzyme) | Â | <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] | Â | 5 [39] |