中文摘要：

目的：研究循环游离DNA（cMNA）在多发性肌炎（PM）和皮肌炎（DM）中的作用。方法：使用PicoGreen试剂盒检测61例PM／DM患者、34例系统性红斑狼疮（SLE）患者和48例健康对照的血浆cfDNA浓度，并与患者的血清学指标做相关性分析。结果：cfDNA浓度在PM／DM组是247．1±61．09ng/ml，显著高于健康对照组（197．1±31．36ng/ml，P〈0．01），显著低于SLE组（281．9±82．21n±ml，P〈0．01）。cfDNA与血沉和血清球蛋白呈显著正相关（P〈0．01，P〈0．05），与C3呈显著负相关（P〈0．01）。结论：cfDNA可能与PM／DM疾病活动度相关。

英文摘要：

Objective：To investigate concentration of plasma circulating cell-free DNA（cfDNA）in patients with polymyositis（PM）and dermatomyositis（DM）.Methods：Sixty one patients with PM/DM ,34 patients with systemic lupus erythematosus （SLE）and 48 age-and sex-matched healthy controls were included in a retrospective, cross-sectional study.The efDNA concentration was measured with PicoGreen Kit.Correlation analysis were performed between cfDNA concentration and other serological markers.Results：efDNA in PM/DM group was 247.1±61.09ng/ml,significantly higher than that in healthy control group （197.1±31.36ng/ml,P〈0.01）and significantly lower than that in SLE group （281.9±82.21ng/ml,P〈0.01）.cfDNA positively correlated with erythroeyte sedimentation rate （P〈0.01）and serum globulin （P〈0.05）, and inversely correlated with C3 （P〈0.01）.Conclusion ： Elevated level of efDNA are involved in PM/DM and may correlate with PM/DM disease activity.