Emergent high fatality lung disease in systemic juvenile arthritis.

OBJECTIVE: To investigate the characteristics and risk factors of a novel parenchymal lung disease (LD), increasingly detected in systemic juvenile idiopathic arthritis (sJIA). METHODS: In a multicentre retrospective study, 61 cases were investigated using physician-reported clinical information and centralised analyses of radiological, pathological and genetic data. RESULTS: LD was associated with distinctive features, including acute erythematous clubbing and a high frequency of anaphylactic reactions to the interleukin (IL)-6 inhibitor, tocilizumab. Serum ferritin elevation and/or significant lymphopaenia preceded LD detection. The most prevalent chest CT pattern was septal thickening, involving the periphery of multiple lobes ± ground-glass opacities. The predominant pathology (23 of 36) was pulmonary alveolar proteinosis and/or endogenous lipoid pneumonia (PAP/ELP), with atypical features including regional involvement and concomitant vascular changes. Apparent severe delayed drug hypersensitivity occurred in some cases. The 5-year survival was 42%. Whole exome sequencing (20 of 61) did not identify a novel monogenic defect or likely causal PAP-related or macrophage activation syndrome (MAS)-related mutations. Trisomy 21 and young sJIA onset increased LD risk. Exposure to IL-1 and IL-6 inhibitors (46 of 61) was associated with multiple LD features. By several indicators, severity of sJIA was comparable in drug-exposed subjects and published sJIA cohorts. MAS at sJIA onset was increased in the drug-exposed, but was not associated with LD features. CONCLUSIONS: A rare, life-threatening lung disease in sJIA is defined by a constellation of unusual clinical characteristics. The pathology, a PAP/ELP variant, suggests macrophage dysfunction. Inhibitor exposure may promote LD, independent of sJIA severity, in a small subset of treated patients. Treatment/prevention strategies are needed.

Race, Income, and Disease Outcomes in Juvenile Dermatomyositis.

OBJECTIVE: To determine the relationships among race, income, and disease outcomes in children with juvenile dermatomyositis (JDM). STUDY DESIGN: Data from 438 subjects with JDM enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Legacy Registry were analyzed. Demographic data included age, sex, race, annual family income, and insurance status. Clinical outcomes included muscle strength, presence of rash, calcinosis, weakness, physical function, and quality of life measures. Disease outcomes were compared based on race and income. RESULTS: Minority subjects were significantly more likely to have low annual family income and significantly worse scores on measures of physical function, disease activity, and quality of life measures. Subjects with lower annual family income had worse scores on measures of physical function, disease activity, and quality of life scores, as well as weakness. Black subjects were more likely to have calcinosis. Despite these differences in outcome measures, there were no significant differences among the racial groups in time to diagnosis or duration of disease. Using calcinosis as a marker of disease morbidity, black race, annual family income <$50 000 per year, negative antinuclear antibody, and delay in diagnosis >12 months were associated with calcinosis. CONCLUSION: Minority race and lower family income are associated with worse morbidity and outcomes in subjects with JDM. Calcinosis was more common in black subjects. Further studies are needed to examine these associations in more detail, to support efforts to address health disparities in subjects with JDM and improve disease outcomes.