酶联免疫吸附试验检测人血清抗双链DNA抗体在系统性红斑狼疮诊断中的性能评估

Clinical Performance of Enzyme Linked Immunosorbent Assay Detecting Serum Antibodies Against Double-stranded DNA in Diagnosis of Systemic Lupus Erythematosus

目的对人血清抗双链DNA(dsDNA)抗体的酶联免疫吸附检测试剂盒Anti-dsDNA-NcX ELISA行实验室检测性能评估及在系统性红斑狼疮(SLE)诊断中的应用评价。方法对Anti-dsDNA-NcX ELISA试剂盒进行实验性能评价;并用间接免疫荧光法(IIF)和酶联免疫吸附法(ELISA)两种方法共三种试剂盒,同时检测健康体检正常者30例、非系统性红斑狼疮自身免疫病患者27例及SLE患者92例血清抗dsDNA抗体。以SLE的临床诊断为金标准,评价Anti-dsDNA-NcX ELISA试剂盒用于SLE的诊断性能。结果 Anti-dsDNA-NcX ELISA试剂盒达到了各项实验室检测性能指标,试剂盒的最低检测限为2.7 U/m l,线性相关系数为0.998,批内精密度变异系数(CV)<6%,批间精密度CV<10%,溶血、脂血、黄疸对检测结果没有干扰,与类风湿性关节炎、干燥综合征等非SLE自身免疫病患者血清间不存在交叉反应。健康体检正常者血清抗dsDNA抗体水平P97.5为67.0 U/m。l92例狼疮性肾炎患者,两种ELISA试剂的阳性率(60.9%)均高于IIF(20.6%),差异有统计学意义(P<0.05),其中Anti-dsDNA-NcXELISA试剂盒诊断狼疮性肾炎的正确率要高于AESKULISA dsDNA-Check ELISA试剂盒(曲线下面积分别为0.90和0.68),差异有统计学意义(P<0.001)。当抗dsDNA抗体取108 U/m l为诊断界值时,Anti-dsDNA-NcX ELISA试剂盒诊断狼疮性肾炎的特异性为98.2%,阳性预测值为96.6%。结论 Anti-dsDNA-NcX ELISA试剂盒各项检测性能良好,诊断狼疮性肾炎在不降低敏感性的基础上提高了特异性和阳性预测值,是目前IIF的有益补充,其试剂可以用于SLE的临床诊断。

Objective To estimate the clinical performance of enzyme linked immunosorbent assay（ELISA） kits（Anti-dsDNA-NcX ELISA） detecting serum antibodies against double-stranded DNA（dsDNA） in the diagnosis of Systemic lupus erythematosus（SLE）.Methods A performance evaluation was carried out on Anti-dsDNA-NcX ELISA kits.Indirect immunofluorescence（IIF） and ELISA（a total of 3 kits） were used to detect serum anti-dsDNA antibodies in 30 healthy subjects,27 non-SLE patients with autoimmune disease and 92 SLE patients.Taking SLE diagnosis as gold standard,the diagnosis performance of Anti-dsDNA-NcX ELISA in SLE was evaluated.Results Anti-dsDNA-NcX ELISA kits were up to the laboratory testing indexes,with the lowest detection limit of 2.8 U/ml,linear correlation coefficient of 0.998,within-run precision of CV6%,between-run precision of CV10%.Hemolysis,lipemia and jaundice did not interfere with the test results,having no cross reaction with serum of patients with non-SLE autoimmune diseases such as rheumatoid arthritis,Sjogren′s syndrome,etc.The anti-dsDNA antibody P97.5 was 67.0 U/ml in healthy subjects.The positive rate of 2 kinds of ELISA reagents（60.9%） was higher than that of IIF（20.6%）,the difference was significant（P〈0.05）,among which the accuracy of anti-dsDNA-NcX ELISA kits significantly higher than that of AESKULISA dsDNA-Check ELISA kits（The areas under the curve were 0.90,0.68,respectively） in diagnosis of lupus nephritis（P〈0.05）.Taking 108U/ml of anti-dsDNA antibody as diagnosis cut-off line,the specificity of Anti-dsDNA-NcX ELISA kits was 98.2%,positive predictive value was 96.6% in diagnosis of lupus nephritis.Conclusion Anti-dsDNA-NcX ELISA kits,having good detection performance and improving specificity and positive predictive value without reducing sensitivity,are beneficial additions for IIF.Its reagent can be used for clinical diagnosis of SLE.