Parkinson disease (PD) is the second most common neurodegenerative disease. Because dopaminergic neuronal loss begins years before motor symptoms appear, a biomarker for the early identification of the disease is critical for the study of putative neuroprotective therapies. Brain imaging of the nigrostriatal dopamine system has been used as a biomarker for early disease along with cerebrospinal fluid analysis of α-synuclein, but a less costly and relatively non-invasive biomarker would be optimal. We sought to identify an antibody biomarker in the blood of PD patients using a combinatorial peptoid library approach. We examined serum samples from 75 PD patients, 25 de novo PD patients, and 104 normal control subjects in the NINDS Parkinson's Disease Biomarker Program. We identified a peptoid, PD2, which binds significantly higher levels of IgG3 antibody in PD versus control subjects (P<0.0001) and is 68% accurate in identifying PD. The PD2 peptoid is 84% accurate in identifying de novo PD. Also, IgG3 levels are significantly higher in PD versus control serum (P<0.001). Finally, PD2 levels are positively correlated with the United Parkinson's Disease Rating Scale score (r = 0.457, P<0001), a marker of disease severity. The PD2 peptoid may be useful for the early-stage identification of PD, and serve as an indicator of disease severity. Additional studies are needed to validate this PD biomarker.

中文翻译：

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帕金森氏病的血液生物标志物：类肽。

帕金森病（PD）是第二常见的神经退行性疾病。由于多巴胺能神经元丧失开始于运动症状出现之前的几年，因此用于疾病早期识别的生物标志物对于研究公认的神经保护疗法至关重要。纹状体黑质纹状体多巴胺系统的脑成像已与α-突触核蛋白的脑脊液分析一起用作早期疾病的生物标志物，但成本较低且相对无创性的生物标志物将是最佳选择。我们试图使用组合类肽库方法鉴定PD患者血液中的抗体生物标志物。我们在NINDS帕金森氏病生物标志物计划中检查了75名PD患者，25例从头PD患者和104名正常对照受试者的血清样本。我们确定了类肽PD2，与对照受试者相比，该抗体结合PD中的IgG3抗体水平更高（P <0.0001），并且在鉴定PD中准确度为68％。PD2类肽在从头识别PD中的准确度为84％。而且，PD中的IgG3水平明显高于对照血清（P <0.001）。最后，PD2水平与疾病严重程度的标志-帕金森氏疾病评分量表评分（r = 0.457，P <0001）呈正相关。PD2类肽可能对PD的早期鉴定有用，并可以作为疾病严重程度的指标。需要其他研究来验证该PD生物标志物。最后，PD2水平与疾病严重程度的标志-帕金森氏疾病评分量表评分（r = 0.457，P <0001）呈正相关。PD2类肽可能对PD的早期鉴定有用，并可以作为疾病严重程度的指标。需要其他研究来验证该PD生物标志物。最后，PD2水平与疾病严重程度的标志-帕金森氏疾病分级量表评分（r = 0.457，P <0001）呈正相关。PD2类肽可能对PD的早期鉴定有用，并可以作为疾病严重程度的指标。需要其他研究来验证该PD生物标志物。