Treatment and clinical outcome of juvenile dermatomyositis.

Autoimmune diseases in pediatric patients are heterogeneous, including systemic lupus erythematosus, juvenile rheumatoid arthritis, and juvenile dermatomyositis (JDM). JDM is a rare autoimmune disease involving multiple body systems and accounts for 85% of idiopathic inflammatory myopathies in children. JDM may lead to death or long-term disability; therefore, investigations into the important prognostic factors for guiding the treatment of JDM are crucial. However, to date, there is no standard guideline for the treatment of JDM. In this issue, Sun et al report a 20-year retrospective analysis of treatment and clinical outcomes to investigate outcomes of JDM in Taiwan and to identify predictors or factors associated with outcomes. The study gives us new insight into JDM. JDM is an immune-mediated inflammatory disease involving the microvasculature of skin and muscle. The most common initial presentations are Gottron’s papules and muscle weakness. The clinical features are associated with systemic vasculopathy and are critical to the diagnosis. However, recent studies have suggested that magnetic resonance imaging is also useful in diagnosing JDM and that it may be used as a disease assessment tool. A recent clinical study showed that peripheral blood regulator T cells (Tregs) of active JDMpatients were less capable of suppressing effector T-cell activation in vitro compared with Tregs of JDM in clinical remission. Therefore, the functional impairment of Tregs plays an important role in JDM inflammation in a proportion of patients with active disease. JDM is a heterogeneous disease and autoantibodies may be potentially useful biomarkers to classify patients into homogeneous subgroups and informon disease prognosis. Autoantibody status and age atdiseaseonsethavealsobeen shownto influence theclinical phenotype and overall prognosis in JDM. In JDM, the development of calcinosis has been reported to be associated with delayed diagnosis, a chronic disease course, and inadequately treated disease. Sun et al reported important prognostic factors of JDM in children for predicting clinical outcomes of such patients. Their findings suggest that calcinosis, skin ulcerations, and muscle weakness may develop several years later during follow-up, because aggressive