Measuring disease activity and response to treatment in rheumatoid arthritis

Introduction: Effective treatment of rheumatoid arthritis (RA) requires suppression of the underlying inflammation. Measurement of such inflammation, the disease activity, is mandatory to target treatment and maximize outcomes. However, this is not as straightforward as it may seem.

Areas covered: The many tools developed to measure disease activity in RA, from composite scores and patient-reported outcomes, to laboratory markers and imaging are discussed, with a focus on their utility in guiding therapy and assessing response. The complex issues in measuring disease activity in RA, whether in clinical trials or normal clinical practice, and in the context of national guidelines and recommendations, available time, and resources are considered.

Expert commentary: The key to effective management of RA is the rapid suppression of inflammation, ideally to remission, with maintenance of such remission. The aim is to prevent disability and maximize quality of life. Central to this is the ability to determine disease activity (potentially open to suppression) as opposed to damage (irreversible). A variety of measures are currently available, allowing better assessment of response to treatment. In the future, the development of predictive biomarkers allowing targeting of drugs may revolutionize this field and render the tools of today redundant.     

Neutrophil proteases degrade autoepitopes of NET-associated proteins

Neutrophils can form neutrophil extracellular traps (NETs) to capture microbes and facilitate their clearance. NETs consist of decondensed chromatin decorated with anti-microbial proteins. Here, we describe the effect of neutrophil proteases on the protein content of NETs. We show that the neutrophil serine proteases degrade several neutrophil proteins associated with NETs. Interestingly, the anti-bacterial proteins associated with NETs, such as myeloperoxidase, calgranulin B and neutrophil elastase (NE), seem to be less susceptible to proteolytic degradation than other NET proteins, such as actin and MNDA. NETs have been proposed to play a role in autoimmune reactions. Our data demonstrate that a large number of the autoepitopes of NET proteins that are recognized by autoantibodies produced by systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients are also removed by the proteases. In conclusion, neutrophil serine proteases have a major impact on the NET proteome and the proteolytic changes of NET-associated proteins may counteract autoimmune reactions to NET components.     

Elevated serum levels of Interleukin‐37 are associated with inflammatory cytokines and disease activity in rheumatoid arthritis

Interleukin‐37 (IL‐37) is closely associated with several inflammatory diseases. However, the role of IL‐37 in the pathogenesis of rheumatoid arthritis (RA) remains unclear. The aim of this study was to assess the associations between serum levels of IL‐37 and disease activity, inflammatory cytokines, and bone loss in patients with RA. Serum cytokines levels were examined by Enzyme‐linked immunosorbent assay (ELISA). Radiographic bone erosion was assessed using the van der Heijde‐modified Sharp score and bone mineral density (BMD) was measured using DXA. Serum IL‐37 levels in RA patients were significantly higher than those in HCs (p < 0.001), and were significantly positively correlated with clinical parameters of disease activity and serum levels of IL‐17 and IL‐23. In addition, serum IL‐37 levels were significantly higher in patients with stage IV of radiographic bone erosion than those with stage III and stage I–II, and they were significantly higher in those with osteopenia and osteoporosis than in those with normal BMD. Our results suggest that serum IL‐37 levels were increased in patients with RA and were positively associated with disease activity, IL‐17/IL‐23 and bone loss in RA, suggesting that IL‐37 may play a critical role in the pathogenesis of RA.     

外周血miR-150-5p、SOCS1 mRNA对类风湿关节炎“病”“证”诊断意义的初步探讨＊

目的 探讨类风湿关节炎患者外周血miR-150-5p、细胞因子信号抑制因子1（suppressor of cytokine signaling 1，SOCS1）mRNA的表达及对类风湿关节炎（Rheumatoid Arthritis，RA）疾病诊断、中医证型判断的意义。方法 纳入符合诊断标准的RA患者57例及健康对照组19例，根据《22个专业95个病种中医诊疗方案》有关RA的中医证候诊断标准，判断RA的中医证型。qPCR检测RA患者及健康对照组miR-150-5p、SOCS1mRNA的相对表达水平，同时检测血常规、肝功能、肾功能等常规指标。双荧光素酶分析方法判断两者是否存在靶向关系。统计分析miR-150-5p、SOCS1 mRNA对RA疾病的诊断意义及其与中医证型的相关性。结果 RA患者外周血miR-150-5p的相对表达水平下调，低于正常人群（t = -19.019，P < 0.05）；其表达水平随疾病活动度升高，有下降趋势；患者外周血SOCS1 mRNA的相对表达水平上调，低于正常人群（t = 5.333，P < 0.05）；其表达水平随疾病活动度升高，有上升趋势。MiR-150-5p与SOCS1 mRNA有靶向结合关系（P < 0.05）。通过AUC曲线比较，miR-150-5p的相对表达水平区分RA的敏感性及特异性分别为98.1%、92.1%（AUC = 0.972，P < 0.05）；SOCS1 mRNA的相对表达水平无法区分RA（AUC = 0.472，P > 0.05）。RA患者中miR-150-5p的相对表达水平低于3.06，RA患者风湿痹阻证、寒湿痹阻证的相对风险分别为8.33、250.00（P < 0.05）。结论 miR-150-5p、SOCS1 mRNA在RA患者中有差异性表达，且有靶向结合关系。miR-150-5p可能是RA的疾病诊断及中医风湿痹阻证、寒湿痹阻证证型诊断的潜在生物标志物。