Recent advances in juvenile idiopathic inflammatory myopathies

Purpose of review: Ongoing research continues to advance our understanding of the juvenile idiopathic inflammatory myopathies (JIIMs). We review the recent contributions from the published literature about the classification, pathogenesis, assessment, and treatment of JIIMs in basic and translational science and clinical research in 2013 through early 2014. Recent findings: Large registries, such as the Childhood Arthritis and Rheumatology Research Alliance registry, are conducting trials to enhance our understanding of JIIMs. Ultraviolet radiation exposure 1 month prior to juvenile dermatomyositis (JDM) may trigger the onset of disease. Myositis-specific autoantibodies define clinical phenotypes in JIIMs. MRI is useful in diagnosing JDM and may be used as a disease assessment tool. Type 1 interferon genes and proteins are increasing in use as disease assessment tools, but larger, prospective, validation studies are needed. Moderate-to-intense physical activity is effective in increasing the aerobic capacity of JDM patients in remission. New criteria developed by the Paediatric Rheumatology International Trials Organization for classifying inactive disease in JDM have practical applicability to the current clinical practice and clinical trials as even after 16.8 years of symptom onset, over half of JDM patients still have active disease. Summary: There has been significant progress in understanding the clinical characteristics, diagnostic workup, treatment, disease assessment, and prognosis of JIIM patients, but more prospective treatment trials are needed, especially in light of the paucity of the current biologic treatment agents available.