BACKGROUND To evaluate the impact of the duration of chronic inflammation on gene expression in skeletal muscle biopsies (MBx) from untreated children with juvenile dermatomyositis (JDM) and identify genes and biological processes associated with the disease progression, expression profiling data from 16 girls with active symptoms of JDM greater than or equal to 2 months were compared with 3 girls with active symptoms less than 2 months. RESULTS Seventy-nine genes were differentially expressed between the groups with long or short duration of untreated disease. Genes involved in immune responses and vasculature remodelling were expressed at a higher level in muscle biopsies from children with greater or equal to 2 months of symptoms, while genes involved in stress responses and protein turnover were expressed at a lower level. Among the 79 genes, expression of 9 genes showed a significant linear regression relationship with the duration of untreated disease. Five differentially expressed genes--HLA-DQA1, smooth muscle myosin heavy chain, clusterin, plexin D1 and tenomodulin--were verified by quantitative RT-PCR. The chronic inflammation of longer disease duration was also associated with increased DC-LAMP+ and BDCA2+ mature dendritic cells, identified by immunohistochemistry. CONCLUSION We conclude that chronic inflammation alters the gene expression patterns in muscle of untreated children with JDM. Symptoms lasting greater or equal to 2 months were associated with dendritic cell maturation and anti-angiogenic vascular remodelling, directly contributing to disease pathophysiology.

中文翻译：

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慢性炎症的持续时间改变了未经治疗的青少年皮肌炎女孩肌肉中的基因表达。

背景 为了评估慢性炎症持续时间对未经治疗的幼年型皮肌炎 (JDM) 儿童骨骼肌活检 (MBx) 基因表达的影响，并确定与疾病进展相关的基因和生物学过程，从 16将大于或等于 2 个月的 JDM 症状与 3 名活动症状小于 2 个月的女孩进行比较。结果 79 个基因在未治疗疾病持续时间长或短的组之间差异表达。在症状大于或等于 2 个月的儿童的肌肉活检中，参与免疫反应和脉管系统重构的基因表达水平较高，而参与应激反应和蛋白质转换的基因表达水平较低。在这 79 个基因中，9个基因的表达与未治疗疾病的持续时间呈显着的线性回归关系。通过定量 RT-PCR 验证了五个差异表达的基因——HLA-DQA1、平滑肌肌球蛋白重链、凝聚素、丛蛋白 D1 和腱调节蛋白。病程较长的慢性炎症也与 DC-LAMP+ 和 BDCA2+ 成熟树突细胞的增加有关，通过免疫组织化学鉴定。结论 我们得出结论，慢性炎症会改变未经治疗的 JDM 儿童肌肉中的基因表达模式。持续大于或等于 2 个月的症状与树突状细胞成熟和抗血管生成血管重塑有关，直接促成疾病的病理生理学。