The aim of the study was to investigate the characteristics of adult clinically amyopathic dermatomyositis (CADM) with rapid progressive interstitial lung disease (ILD). Hospitalized patients with dermatomyositis (DM) and polymyositis (PM) between 1998 and 2005 in the Shanghai Renji Hospital were retrospectively studied. One hundred and forty-five patients were classified into CADM, classic DM or PM according to the modified Sontheimer's definition or Bohan-Peter's classification criteria. They were further stratified based on the presence or absence of clinical ILD. The Kaplan-Meier survival analysis and COX regression were performed. The predictive factors for ILD and other clinical properties of CADM-ILD were explored. The presence of clinical ILD was a significant risk factor for the poor outcome of DM/PM (OR = 4.237, CI 95%: 1.239-14.49, p = 0.021). Other risk factors are the presence of rashes and elevated urea nitrogen. Patients with DM/PM complicated by ILD had different clinical courses. Patients with CADM-ILD showed a rapidly progressive pattern with 6-month survival rate of 40.8%. The DM-ILD manifested a progressive pattern with a 5-year survival rate of 54%, while PM-ILD was chronic with 5- and 10-year survival rate of 72.4% and 60.3%, respectively. Better preserved muscle strength, elevated erythrocyte sedimentation rate, and hypoalbuminemia may herald ILD in DM/PM. Patients with CADM-ILD who later died had lower PO(2), higher lactate dehydrogenase, and prominent arthritis/arthralgia compared with those who survived. The presence of antinuclear antibody seems to be protective. Rapid progressive CADM-ILD is refractory to conventional treatment. ILD is a common complication in over 40% of our hospitalized DM/PM cohort and is also a prominent prognostic indicator. CADM is a special phenotype of DM/PM. CADM-ILD, which is usually rapidly progressive and fatal, requires further investigation.

Patients with AOSD had complex symptoms with no specific laboratory findings. Our results indicate that AOSD is not a relatively benign disease, especially in cases that are refractory to high doses of prednisone.

BackgroundAdult-onset Still’s disease (AOSD) is a systemic inflammatory disease characterized by neutrophilia and NLRP3 inflammasome and macrophage activation. We investigated the role of neutrophil extracellular traps (NETs) in the pathogenesis of AOSD, and explored the effect of NETs on activating NLRP3 inflammasome and proinflammatory macrophages.MethodsThe sera of 73 AOSD patients and 40 healthy controls were used to detect the level of cell-free DNA and NET-DNA complexes. NET formation ex vivo was analyzed using immunofluorescence and flow plates. The activation of NLRP3 inflammasome in THP-1 cells and proinflammatory macrophages stimulated with DNA purified from NETs was measured using RT-PCR, ELISA, Western blotting and flow cytometry.ResultsThe levels of cell-free DNA and NET-DNA complexes were significantly increased in the circulation of patients with AOSD compared with healthy controls, and freshly isolated neutrophils from patients with AOSD were predisposed to high levels of spontaneous NET release. Interestingly, enhanced NET release was abrogated with NADPH oxidase inhibitors and a mitochondrial scavenger. Furthermore, DNA purified from AOSD NETs activated NLRP3 inflammasomes. NET DNA from AOSD also exerted a potent capacity to accelerate the activation of CD68+CD86+ macrophages and increased the expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. Finally, the copy number of mitochondrial DNA (mtDNA) in NETs and plasma was significantly increased in AOSD patients, suggesting that mtDNA may be involved in the activation of NLRP3 and inflammatory macrophages.ConclusionsThese findings implicate accelerated NET formation in AOSD pathogenesis through activation of NLRP3 and proinflammatory macrophages, and identify a novel link between neutrophils and macrophages by NET formation in AOSD.Electronic supplementary materialThe online version of this article (10.1186/s13075-018-1800-z) contains supplementary material, which is available to authorized users.