Liewluck, Teerin

Abstract Objective Myositis is a heterogeneous family of inflammatory myopathies. We sought to define the differential expression of cytokines, cytokine receptors and immune checkpoint genes in muscle biopsies from patients with different forms of myositis in order to characterize patterns of inflammation in each. Methods Bulk RNA-sequencing was performed on muscle biopsy samples from 669 patients, including 105 with DM, 80 with immune-mediated necrotizing myopathy (IMNM), 65 with anti-synthetase syndrome, 53 with IBM, 19 with anti-PM/Scl myositis, 310 with other inflammatory or genetic myopathies and 37 controls with normal tissue (NT). Myositis clinical groups and autoantibody subgroups were analysed separately. Expression data were analysed for 338 genes encoding cytokines, cytokine receptors and immune checkpoints. Myositis group-specific genes were identified from this list by finding genes that were specifically differentially expressed in one group compared with all samples and compared with NT (α < 0.001). Results IBM patients had the most differentially overexpressed genes (71) among all clinical groups, including 37 that were IBM-specific. Among the top genes were several involved in type 1 inflammation, including CCL5, CXCR3, CCR5, CXCL9 and IFNG. Anti-Jo1 and anti-PM/Scl patients exhibited differential overexpression of a similar set of genes, while DM patients exhibited differential overexpression of a different set of genes involved in type 1 inflammation. IMNM patients had the least number of differentially overexpressed genes with no predominant inflammatory pattern. Conclusion Each myositis clinical group and autoantibody subgroup had differentially overexpressed inflammatory mediators, including a strong type 1 inflammatory gene signature in IBM.

Abstract Objectives The lack of uniform terminology and abbreviations for anti-synthetase syndrome has led to significant challenges in research and clinical practice. This study aimed to establish an international consensus on a standardized nomenclature and abbreviation among a diverse group of global myositis experts and patient representatives. Methods This qualitative project was approved by the International Myositis Assessment and Clinical Studies Group (IMACS). Based on the outcomes of a literature review and preliminary survey, list of terms for nomenclature and abbreviations was finalized. Subsequently, two rounds of the Delphi survey were conducted among myositis experts and patient participants to ascertain current practices and preferences. Using Nominal Group Technique (NGT), the project steering committee developed a consensus nomenclature and abbreviation. Results A total of 241 and 132 myositis experts from six continents, 35 countries and 9 specialities participated in round 1 and round 2 of the Delphi survey, respectively. The results indicated a preference for the terms anti-synthetase syndrome, antisynthetase syndrome and anti-tRNA synthetase syndrome. The abbreviations ASS, ASyS and ASSD were most used, though ASS received notable disapproval. The steering committee, including twenty-five myositis experts and three patient representatives from diverse backgrounds and geographical locations, reached a consensus on ‘anti-synthetase syndrome’ as the preferred nomenclature and ASyS as the preferred abbreviation, with 100% and 93.1% votes, respectively. Conclusion The terms anti-synthetase syndrome and ASyS should be adopted as the standard nomenclature and abbreviation in both research and clinical practice. This standardization is expected to increase consistency within the literature.

ABSTRACTCavin‐4 was identified as a potential autoantigen for immune‐mediated rippling muscle disease (iRMD). To validate this, we developed and tested various immunoassays, including a cell‐based assay (CBA), cavin‐4 recombinant protein ELISA, and multi‐peptide ELISA. Among 19 iRMD patients, all exhibited muscle rippling, and 13 had percussion‐induced mounding. All immunoassays demonstrated clinical and analytical specificities greater than 95%. The protein ELISA had the highest sensitivity (94.7%) and specificity (99.9%), outperforming CBA (sensitivity 89.5%, specificity 99.6%) and the multi‐peptide ELISA (sensitivity 79.0%, specificity 97.2%). Our results suggest that the cavin‐4 protein ELISA is a promising tool for high‐throughput clinical testing in iRMD.