Gene Expression Biomarkers for Diagnosis of Lyme Disease

描述（由申请人提供）：莱姆病是美国最常见的蜱传传染病，其发病率和范围都在增加。早期诊断和治疗莱姆病是预防疾病进展和后遗症的关键。目前的实验室诊断主要是血清学分析，它们在许多关键领域失败。它们在早期莱姆病中特异性不足，不敏感，不能确定治疗反应。更重要的是，由于血清学检测是基于抗体的存在，它们无法区分活动性感染和由于先前已解决的伯氏疏螺旋体感染而引起的免疫记忆。需要新的范例和分析方法来弥补我们诊断能力中的这些差距。在此，我们提出一种新的方法。我们将利用差异基因表达分析来确定莱姆病患者血液中对伯氏疏螺旋体的标志性反应，其长期目标是开发一种可靠的基于基因的活动性感染诊断测试。具体而言，我们建议：1)使用微阵列分析鉴定活动性莱姆病患者外周血单个核细胞（PBMCs）中差异表达的基因，并将结果与健康供者的外周血单个核细胞（PBMCs）进行比较；2)利用预测因子选择的监督学习方法，鉴定出一组预测伯氏疏螺旋体感染的判别基因，而不是其他常见的血源性细菌病原体的感染；3)通过实时RT-PCR技术，评估症状消退患者在标准抗生素治疗后获得的成对急性和恢复期患者样本中鉴定为伯氏疏螺旋体特异性指示基因的基因表达水平。这将提供在成功治疗的患者中随时间的基因表达信息，并应定义活跃而非消退的伯氏疏螺旋体感染特征的鉴别基因子集。这些研究预计将导致确定一组明确的指示基因，这些基因在活动性莱姆病患者中受到显著和独特的调节，而不是在已成功接受抗生素治疗的患者或患有其他常见血源性细菌感染的个体中。一旦确定，这一分类基因子集可以作为开发灵敏和特异性的活动性伯氏疏螺旋体感染诊断测试的基础。

DESCRIPTION (provided by the applicant): Lyme disease is the most frequently reported tick-borne infectious disease in the United States and both its incidence and range are increasing. Early diagnosis and treatment of Lyme disease is critical to prevent disease progression and sequellae. Current laboratory diagnostics are primarily serologic assays and they fail in a number of key areas. They are insufficiently specific, not sensitive in early Lyme disease and cannot determine treatment response. More importantly, because serological assays are based on the presence of antibodies, they are incapable of discriminating between active infection and immunological memory due to prior, resolved infection with Borrelia burgdorferi. New paradigms and assays are needed to address these gaps in our diagnostic capabilities. Here we propose a new approach. We will utilize differential gene expression analysis to identify a signature response to B. burgdorferi in the blood of Lyme disease patients, with the long-term objective of developing a reliable gene-based diagnostic test for active infection. Specifically we propose to: 1) use microarray analysis to identify genes differentially expressed in peripheral blood mononuclear cells (PBMCs) isolated from patients with active, culture-confirmed Lyme disease and compare the results to PBMCs from healthy donors; 2) identify a set of discriminator genes predictive of B. burgdorferi infection, as opposed to infection by other common blood-borne bacterial pathogens, using a supervised learning approach of predictor selection; 3) assess expression levels of genes identified as B. burgdorferi-specific indicator genes by real-time RT-PCR in paired acute and convalescent patient samples obtained following standard antibiotic treatment in patients with resolution of symptoms. This will provide information on the gene expression over time in successfully-treated patients and should define a subset of discriminator genes characteristic of active, as opposed to resolved, B. burgdorferi infection. These studies are expected to result in the identification of a defined set of indicator genes which are significantly and uniquely regulated in patients with active Lyme disease as opposed to patients that have been successfully treated with antibiotics or individuals with other common blood-borne bacterial infections. Once identified, this subset of classifier genes can serve as the basis for development of a sensitive and specific diagnostic test for active B. burgdorferi infection. PUBLIC HEALTH RELEVANCE: Lyme disease, the most frequently reported tick-borne disease in the United States, is caused by infection with the spirochete Borrelia burgdorferi and diagnosis is currently based on serological tests which lack sensitivity and specificity, especially in early disease, and do not discriminate between active infection and prior, resolved infection with B. burgdorferi. The proposed studies are expected to result in the identification of a defined set of indicator genes which are significantly and uniquely regulated in patients with active Lyme disease as opposed to patients with other common blood-borne bacterial infections or individuals with antibiotic-treated, resolved Lyme disease with or without ongoing symptoms. Once identified, this subset of classifier genes could be employed as the basis for development of a sensitive and specific gene-based diagnostic test for active B. burgdorferi infection.