Anti-signal recognition particle autoantibody ELISA validation and clinical associations
Anti-signal recognition particle autoantibody ELISA validation and clinical associations
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DOI：
10.1093/rheumatology/keu436
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发表时间：
2015-07-01
期刊：
影响因子：
5.5
通讯作者：
Levesque, Marc C.
中科院分区：
文献类型：
--
作者：
Aggarwal, Rohit;Oddis, Chester V.;Levesque, Marc C.
Objective.本研究的目的是开发和验证定量抗信号识别颗粒（SRP）自身抗体血清ELISA在肌炎患者和纵向与肌炎疾病活动度的关联。我们使用包被在ELISA板上的重组纯化的全长人SRP和结合人IgG的二抗开发了血清ELISA以检测抗SRP结合。蛋白质免疫沉淀用作抗SRP存在的金标准。分析来自三组的血清样品：SRP（+）肌炎受试者通过免疫沉淀，SRP（-）肌炎受试者通过免疫沉淀和非肌炎对照。评价该方法的敏感性、特异性、阳性预测值和阴性预测值。百分比协议和重测信度进行了评估。从7名SRP免疫沉淀阳性受试者中采集的系列样本也进行了检测，沿着血清肌酶和手工肌肉测试。使用免疫沉淀法，我们确定了26名SRP（+）肌炎患者和77名SRP（-）对照（包括38名坏死性肌病患者）。非肌炎对照患者包括SLE（n = 4）和SSc（n = 7）患者。ELISA法检测抗SRP抗体阳性率与免疫沉淀法检测结果一致率为97.1%（kappa = 0.94）。抗SRP ELISA的敏感性、特异性、阳性预测值和阴性预测值分别为88、100、100和96。曲线下面积为0.94，重测信度较强（r = 0.91，P < 0.001）。系列样品显示抗SRP水平与肌肉酶和手工肌肉测试的变化有关。我们建立了一种定量ELISA检测血清抗SRP自身抗体，并验证了肌炎的测定。通过ELISA对SRP水平的纵向评估可能是疾病活动的有用生物标志物。
Objective. The aim of this study was to develop and validate a quantitative anti-signal recognition particle (SRP) autoantibody serum ELISA in patients with myositis and longitudinal association with myositis disease activity.Methods. We developed a serum ELISA using recombinant purified full-length human SRP coated on ELISA plates and a secondary antibody that bound human IgG to detect anti-SRP binding. Protein immunoprecipitation was used as the gold standard for the presence of anti-SRP. Serum samples from three groups were analysed: SRP(+) myositis subjects by immunoprecipitation, SRP(-) myositis subjects by immunoprecipitation and non-myositis controls. The ELISA's sensitivity, specificity, positive predictive value and negative predictive value were evaluated. Percentage agreement and test-retest reliability were assessed. Serial samples from seven SRP immunoprecipitation-positive subjects were also tested, along with serum muscle enzymes and manual muscle testing.Results. Using immunoprecipitation, we identified 26 SRP(+) myositis patients and 77 SRP(-) controls (including 38 patients with necrotizing myopathy). Non-myositis control patients included SLE (n = 4) and SSc (n = 7) patients. Anti-SRP positivity by ELISA showed strong agreement (97.1%) with immunoprecipitation (kappa = 0.94). The sensitivity, specificity, positive predictive value, and negative predictive value of the anti-SRP ELISA were 88, 100, 100 and 96, respectively. The area under the curve was 0.94, and test-retest reliability was strong (r = 0.91, P < 0.001). Serial samples showed that anti-SRP levels paralleled changes in muscle enzymes and manual muscle testing.Conclusion. We developed a quantitative ELISA for detecting serum anti-SRP autoantibodies and validated the assay in myositis. Longitudinal assessment of SRP levels by ELISA may be a useful biomarker for disease activity.