Myositis specific autoantibodies (MSAs) are specific for the diagnosis of myositis. They are mutually exclusive and have been reported to be associated with a unique clinical phenotype. On the other hand, myositis associated autoantibodies (MAAs) are not specific. They are often seen in association with overlap diseases and their clinical significance has not been studied in detail.
This study from Childhood Myositis Heterogeneity Collaborative Study Group reports the clinical significance of presence of MAAs in a large cohort of 551 patients with juvenile myositis (36% patients had at least one MAA while 13% patients had more than one MAAs). There was a higher frequency of overlap with systemic lupus erythematosus, systemic scleroderma and Sjogren syndrome in MAA positive patients. Positivity for MAA was associated with arthritis, Raynaud phenomenon, sclerodactyly, panniculitis, dysphagia, interstitial lung disease, regurgitation, a chronic refractory disease course, worse outcome and mortality. Even though patients with anti NXP-2 autoantibodies were less likely to have MAAs, a subgroup of patients with anti NXP-2 and MAA positivity were more likely to have a refractory disease course and higher requirement of immunosuppressive medications. The number of MAAs was also associated with mortality.
Kawasaki disease (KD) is a medium vessel vasculitis, often seen in children below the age of 5. KD shock syndrome (KDSS) is a serious complication in the acute phase of the disease and patients with KDSS are at increased risk of coronary artery complications.
This single center study from China used a logistic regression prediction model to predict KDSS in a cohort of 74 children with a confirmed diagnosis of KDSS. Results of the study suggest that presence of persistent rash, high pro brain natriuretic peptide (pro BNP), hyponatremia, hypophosphatemia and elevated aspartate aminotransferase (AST) were independent predictors of KDSS.
Uveitis is the most common extra-articular complication in juvenile idiopathic arthritis (JIA) and is an important cause of visual morbidity. Methotrexate is a commonly used DMARD for treatment of patients with JIA associated uveitis. A proportion of patients, however, fail to respond to methotrexate. They are at risk of increased ocular damage and may benefit from early introduction of biologic DMARDs.
This study analyzed data from 99 JIA associated uveitis patients treated with methotrexate to identify predictors of non-response to methotrexate. Approximately 66% of patients required at least one biologic DMARD to control the inflammation. It was observed that younger age of onset of JIA and uveitis; a polyarticular course of the disease; bilateral uveitis and use of systemic steroids were significantly associated with non-response to methotrexate.
