Role of Infectious Agents in Pediatric Crohn's Disease

这份R03提案将开发和标准化适当的临床和实验室方法，以调查儿童克罗恩病(CD)的潜在感染病因。我们的目标是通过独特的、有效的实验室检测来标准化样品的获取、加工和测试，以检测儿童肠道活检中选定的感染源，并评估不同对照样品的适宜性。未来研究，以检验是否感染(S) 导致儿童CD或确定其发病率需要这些工具和方法。CD的病理生物学尚不清楚。有人提出，一种或多种感染性病原体在遗传易感宿主体内沉淀CD，在儿童CD中可能更容易识别某些病原体。目前的科学证据不能证明因果关系，尽管对一些特定微生物(例如，肠道粘附性大肠杆菌、麻疹病毒)进行了研究。为了检验传染性假说， 必须开发有效的诊断工具，并在采用统一病例和对照定义的具有良好特征的儿童和成人队列中进行测试。儿童和成人发病CD的差异可能意味着危险因素的差异：儿童可能有更严重的肠道疾病，结肠癌风险增加和更早的并发症发生。儿童，特别是新发病的儿童，可能是研究环境因素(例如感染)的独特人群，因为较年轻的儿童接触史较短且较不复杂。 混乱的分析。由6个地理位置不同的大型美国中心组成的儿科IBD联盟是一个极好的平台，可以调查CD的潜在感染诱因，评估并在综合数据库中记录每年约288例新诊断的儿童CD病例的临床和流行病学数据。我们的应用程序建议，从统一定义的联合病例中充分收集肠道活检组织，并进行对照和验证 可以实现灵敏和特定的实验室工具来检测这类标本中潜在的CD感染触发因素。我们的R03旨在：1)标准化收集(例如，解剖来源)、处理和储存在具有良好特征的CD儿童和具有良好特征的对照组的临床指征的内窥镜检查期间获得的胃肠道活检； 2)定义、标准化和验证“适当的”对照、病例的“非病态”活检与非IBD(如先天性巨结肠症)儿童的临床指示活检；3)通过基于病理的(IHC、ISH)、基于广泛扩增的(PCR)和特定生物体(例如MAP)的分子分析来标准化和验证这些样本中某些感染病原体的检测，并通过培养完成MAP和病原体的定位 在病变组织内。同时还将进行肠道活检与来自病例和对照的粪便样本上的基因阵列的比较，以确定本土结肠微生物群的作用。随后，将这一建议开发的方法和系统应用于独特的大型、特征良好的Consortium队列，将优化CD和非疾病之间的差异检测。

This R03 proposal will develop and standardize an appropriate clinical and laboratory approach to investigating potential infectious etiologies of pediatric Crohn's disease (CD). We aim to standardize specimen procurement, processing and testing with unique, validated laboratory assays to detect select infectious agents in pediatric intestinal biopsies, and evaluate the appropriateness of different control specimens. Future studies to test whether infection(s) cause pediatric CD or determine its morbidity demand these tools and methods. CD pathobiology is unclear. It has been proposed that one or more infectious agents precipitate CD in a genetically susceptible host and it may be easier to identify some agents in childhood CD. Current scientific evidence does not prove causality, despite research on a number of specific microbes (e.g., enteroadherent Escherichiae coli, measles virus). To test infectious hypotheses, valid diagnostic tools must be developed and tested in well-characterized cohorts of children as well as adults employing uniform case and control definitions. Differences between childhood and adult onset CD might signify risk factor differences: children can have more severe intestinal disease, increased risk of colon cancer and earlier complication onset. Children, particularly with new onset disease, may represent a unique population to study environmental factors (e.g., infection), since younger age brings shorter and less complicated exposure histories to confound analyses. The Pediatric IBD Consortium of 6 large, geographically diverse U.S. centers represents an excellent platform to investigate potential infectious triggers of CD, evaluating and recording clinical and epidemiologic data on approximately 288 newly diagnosed pediatric CD cases per year in a comprehensive database. Our application proposes that adequate collection of intestinal biopsies from uniformly-defined Consortium cases and controls and validation of sensitive and specific laboratory tools to detect potential infectious triggers of CD in such specimens can be achieved. Our R03 aims to: 1) standardize collection (e.g., anatomic source), processing and banking of gastrointestinal biopsies obtained during clinically-indicated endoscopy of well-characterized children with CD and well-characterized controls; 2) define, standardize and verify "appropriate" controls, "non-diseased" biopsies from cases vs. clinically-indicated biopsies from children without IBD (e.g., Hirschsprung's disease); 3) standardize and validate detection of certain infectious agents in these specimens through pathology-based (IHC, ISH), broad-range amplification-based (PCR) and organism-specific (e.g., MAP) molecular analysis complemeted by culture for MAP and localization of pathogens within diseased tissue. Parallel comparisons of intestinal biopsies to gene arrays on stool specimes from cases and controls to ascertain the role of indigenous colonic microflora will also be performed. Subsequent prospective application of methods and systems developed by this proposal to the uniquely large, well characterized Consortium cohort will optimize detecting differences between CD and non-disease.