DNaseⅠ在多发性肌炎和皮肌炎中的作用

Contribution of DNaseⅠin patients with polymyositis and dermatomyositis

目的研究DNaseⅠ在多发性肌炎和皮肌炎发病机制中的作用。方法选择2011年12月至2012年10月在中日友好医院风湿免疫科住院患者中符合多发性肌炎(PM)/皮肌炎(DM)诊断标准的61例患者作为病例组。同期选择48例健康成年人作为对照组。辐射状酶扩散法测定血浆Ⅰ型脱氧核糖核酸酶(DNaseⅠ)活性,并与患者血清学指标进行相关性分析。在DNaseⅠ活性受损的患者血浆中添加外源性DNaseⅠ和微球菌核酸酶(MNase),进一步分析DNaseⅠ活性受损的原因。结果 DNaseⅠ活性在PM/DM组为(0.3353±0.1894)U/ml,显著低于健康对照组[(0.5441±0.2536)U/ml,P<0.0001]。36例DNaseⅠ活性显著受损的患者血浆中添加外源性重组DNaseⅠ后,11例患者的血浆不能明显恢复DNaseⅠ活性,而添加MNase后,患者血浆对底物dsDNA的降解完全恢复,说明这些患者血浆中存在DNaseⅠ的特异性抑制剂。相关性分析提示DNaseⅠ活性与血清球蛋白(r=0.366,P=0.005)和IgG(r=0.322,P=0.012)呈正相关。结论 PM/DM患者血浆DNaseⅠ活性显著低于健康对照;部分PM/DM患者血浆中存在DNaseⅠ的特异性抑制剂;DNaseⅠ的活性受损可能在PM/DM发病中起一定作用。

Objective To investigate activity of plasma DNaseⅠin patients with polymyositis （ PM ） and dermatomyositis （ DM ） .Methods From the Department of Rheumatology of China-Japan Friendship Hospital （ December 2011 to October 2012 ） ,61 patients who satisfied the Bohan ＆amp; Peter criteria for PM/DM were recruited for this study.To form a control group,48 age and sex-matched healthy Chinese adults were selected during the same period.DNaseⅠactivity was measured by radial enzyme-diffusion method.The mechanism of impaired DNaseⅠactivity was further analyzed by adding exogenous DNaseⅠand MNase to plasma samples .Correlation analysis were performed between DNase I activity and other serological items .Results DNaseⅠactivity in PM/DM group was （0.3353 ±0.1894 ） U/ml,significantly lower than that in healthy control group [（0.5441 ±0.2536 ） U/ml,P 〈0.0001 ] .Eleven patients with PM/DM cannot completely restore DNaseⅠactivity by adding exogenous DNaseⅠbut restore DNaseⅠactivity after being added MNase , indicating specific inhibitor of DNaseⅠoccurring in plasma of these patients .DNaseⅠactivity positively correlated with globulin （ r=0.366 , P=0.005 ） and IgG （ r=0.322 , P=0.012）.Conclusion DNaseⅠactivity is impaired in PM/DM patients.Specific inhibitors of DNaseⅠoccur in plasma of a subset of PM/DM patients.Impaired DNaseⅠactivity may play a role in pathogenesis of PM/DM.