Clinical characteristics and poor predictors of anti-NXP2 antibody-associated Chinese JDM children

Abstract

Background. Juvenile dermatomyositis (JDM) is a rare and sometimes fatal disease in children. The anti-NXP2 antibody is one of the most common antibodies and muscle ischaemia associated with NXP2 autoantibodies was a severe subtype of JDM.Further information is needed regarding clinical characteristics and factors associated with poor prognosis. But there are no reports about clinical characteristics and high risk factor of poor prognosis. For the first time, we introduced the clinical characteristics and poor predictors of anti-NXP2 antibody-associated juvenile dermatomyositis in Chinese children.Methods. Twenty-six patients with anti-NXP2 antibody-related JDM from 85 JDM Chinese patients were diagnosed from January 2016 to November 2019 . Logistic regression was used to analyze the risk factors for refractory cases and mortality.Results. The ratio of male to female was 1:1.9.. The median age of onset was 4.5 (1-13) years. Twenty-four cases (92.3%) had rash and muscle weakness. Treatments included glucocorticoids, immunosuppressive agents, biological agents (7 cases), plasma exchange, Janus kinase inhibitor (7 cases) and autologous stem cell transplant (1 case). Refractory JDM patients (11/26,42.3%) were associated with edema, skin ulcer, muscle strength<=grade 3, CD4/CD8 ratio <1.4 and ferritin >200ug/ml. Among 6 cases (6/26, 23.1%) with severe gastrointestinal involvement, 5 cases died and 1 case survived after autologous stem cell transplant (ASCT). The risk factors for gastrointestinal involvement and mortality were edema, skin ulcer, severe muscle weakness (dysphagia/ hoarseness/ soft voice), BMI<15 and ANA positive.Conclusions. . Edema, skin ulcer and severe muscle weakness predicted refractory disease, GI involvement, and mortality in anti-NXP2 antibody-positive JDM of Chinese children. Decreased CD4/CD8 ratio and high ferritin related with refractory cases, and very low BMI and ANA (+) are probably, associated with gastrointestinal involvement and mortality .

A Continuous Increase in CXC-Motif Chemokine Ligand 10 in a Case of Anti-Nuclear Matrix Protein-2-Positive Juvenile Dermatomyositis

“…Additionally, several risk factors for a refractory clinical course among patients with anti-NXP2-positive JDM have been reported. Wang et al [13] reported an analysis of 26 anti-NXP2-positive JDM cases and found that edema, skin ulcers, significant muscle weakness, low CD4/CD8 ratio and high serum ferritin level at disease onset were associated with a refractory clinical course. Importantly, the serum levels of muscular enzymes at onset did not provide a basis for differentiating clinical outcomes.…”

A systematic review on biological therapies in juvenile idiopathic inflammatory myopathies: an evidence gap in precision medicine

“…The presence of anti-NXP2 antibody is associated with histological features of severe muscle ischaemia, thus leading to profound muscular weakness, and high risk of gastrointestinal perforation, due to a severe vasculopathy. This JIIM phenotype often requires multiple immunosuppressive treatments (7). Anti-signal recognition particle (SRP) and anti-hydroxy-metylglutaryl coenzyme A reductases (HMGCO) antibodies features a different phenotype char-acterised by severe necrotising myositis, with scant inflammatory infiltrates and mild or absent skin involvement, and a severe disease course with need of multiple immunosuppressive treatment (8).…”