Host-derived biomarker signatures for the diagnosis of acute rickettsial diseases

立克次体疾病，如由斑点热群立克次体和丛林斑疹伤寒引起的疾病 据估计，全世界每年有数百万人死于(ST)疾病。SFGR感染影响退伍军人和 美国各地的其他公众以及SFGR和丛林斑疹伤寒都在不断威胁着 驻扎在世界各地的现役战士。有效的治疗方法是存在的，但目前还没有临床应用。 能够在指导所需的时间范围内提供可靠诊断信息的可用测试 治疗决定。通过这项提议，我们打算探索自然人类感染的病理生理学。 以及由主机响应定义的SFGR和ST，并利用该信息来生成实际测试 能够在急诊情况下诊断这些疾病。之前发表的工作和我们的初步数据表明 这些立克次体感染在人类宿主中触发保守的炎症途径，正是这些独特的途径 我们将利用宿主反应来确定循环白血中基因表达的模式 在发烧的病人身上识别这些微生物存在的细胞。为了生成这样一个签名 感染方面，该项目将利用两个主要临床队列的独特组合。第一组由以下人员组成 在美国确诊患有急性立克次体疾病的美国退伍军人，都曾登记过急性立克次体疾病患者 SFGR感染以及正在登记的新病例。第二批人是由一大批现有的 从世界各地登记的患有各种急性发热性SFGR感染的个体样本集 作为丛林斑疹伤寒，我们已经展示了模拟在SFGR感染中看到的宿主反应。这种组合 将使我们能够产生立克次体基因签名，既识别这里的退伍军人的急性疾病 在美国，并有潜力在我们的边界以外的旅行者和现役军人的效用 驻扎在国际上的成员。我们将利用RNA测序(RNAseq)来识别复杂的模式 其他类型发热性疾病受试者和对照组外周血中基因表达的研究 (包括来自美国和全球的病毒和细菌感染)。然而，高维RNAseq 分析不是一种可以在临床相关的时间范围内产生诊断答案的方式。因此，我们 将这些复杂的签名(S)削减到适合RT-PCR平台的更小的基因组分类器， AS使用RT-PCR探针既适用于现有的临床实验室基础设施，也适用于许多 正在开发中的新兴的护理点平台，从而开始了实现这种测试的最后步骤 达到了真正的临床实用的程度。因此，通过这一提议，我们打算探索糖尿病的病理生理学。 由宿主反应定义的自然人感染SFGR和丛林斑疹伤寒，并利用这一点 用于构建具有诊断能力的基于系统的模型的信息。因此，我们期望不仅是 这些实验会为我们提供有关宿主反应中一个基本上未被探索的方面的令人兴奋的新数据吗？ 对具有真正全球影响的感染，但它们将为将这些发现转化为实践奠定基础 对公众和退伍军人健康有直接影响的应用。

Rickettsial diseases such as those caused by Spotted Fever Group rickettsii (SFGR) and Scrub typhus (ST) are estimated to account for millions of illnesses a year worldwide. SFGR infections affect Veterans and other members of the public throughout the US, and both SFGR and Scrub typhus are continuous threats to active duty warfighters stationed throughout the world. Effective therapy exists, but there is currently no clinically available test capable of yielding reliable diagnostic information within the timeframe required to guide therapeutic decisions. Through this proposal we intend to explore the pathophysiology of natural human infection with SFGR and ST as defined by the host response, and to utilize this information to generate a practical test capable of diagnosing these diseases in the acute setting. Prior published work and our preliminary data suggest that these rickettsial infections trigger conserved inflammatory pathways in human hosts, and it is these unique host responses that we will harness in order to identify patterns of gene expression within circulating white blood cells that identify the presence of these organisms in febrile patients. In order to generate such a ‘signature’ of infection, this project will utilize a unique combination of two main clinical cohorts. The first cohort is made up of US Veterans with acute rickettsial illness diagnosed here in the US, both previously enrolled patients with acute SFGR infection as well as ongoing enrollment of new cases. The second cohort is made up of a large existing sample set of individuals enrolled from around the world with a variety of acute febrile SFGR infections as well as Scrub typhus, which we have shown mimics the host responses seen in SFGR infection. This combination will give us the ability to generate a rickettsial gene signature that both identifies acute disease in Veterans here in the US as well as having the potential for utility beyond our borders for travelers and active duty military members stationed internationally. We will utilize RNA Sequencing (RNASeq) to identify complex patterns of gene expression in peripheral blood samples from subjects and controls with other types of febrile illnesses (including viral and bacterial infections, both from the US and globally). However, high dimensional RNASeq analysis is not a modality that can produce diagnostic answers in a clinically relevant timeframe. Therefore, we will ‘prune’ these complex signature(s) down to smaller genomic classifiers appropriate for RT-PCR platforms, as using RT-PCR probes lends itself to both existing clinical laboratory infrastructure as well as to a number of burgeoning point-of-care platforms in development, thus beginning the final steps towards bringing such a test to the point of actual clinical utility. Thus, through this proposal we intend to explore the pathophysiology of natural human infection with SFGR and Scrub typhus as defined by the host response, and to utilize this information to build systems-based models with diagnostic capability. It is therefore our expectation that not only will these experiments provide us with exciting new data about a largely unexplored aspect of the host response to infections with true global impact, but that they will lay the foundation for translating these findings into practical applications with a direct impact on public and Veteran health.