Immunologic and Virologic Correlates of the Age-Related Decrease in HBV DNA in Children

描述（由申请方提供）：儿童B型肝炎病毒感染是一个重要的公共卫生问题，大多数儿童通过母胎获得HBV，使他们处于肝硬化和/或肝细胞癌（HCC）的高终身风险（约25 - 50%）。HBe抗原（HBeAg）阳性和持续高水平的HBV DNA是成人肝硬化和HCC的独立危险因素。虽然对儿童对HBV DNA的免疫应答知之甚少，但我们观察到HBRN中年龄较大的儿童与年轻受试者相比，HBeAg清除率较高，HBV DNA水平较低。因此，仔细研究不同年龄儿童对HBV抗原和细胞因子/趋化因子模式的T细胞应答可能揭示与病毒清除相关的免疫决定因素，并在未来改善抗病毒治疗。该应用程序的总体目标有两个方面：1）继续招募和招募儿童参加儿科HBRN研究，并保留156名（儿科队列）和31例已由约翰霍普金斯儿科临床中心入组的免疫耐受（IT）受试者（约翰霍普金斯的儿科肝脏中心，UTSW和华盛顿大学2）描述2个年龄组HBV感染儿童的T细胞免疫表型和对HBV抗原的应答以及细胞因子趋化因子模式，10岁vs 10 - 18岁，与年龄和性别匹配的未感染对照组和成人现有T细胞数据相比。T细胞的免疫表型将通过染色（多色FACS）表征。将探索体外阻断抑制途径如PD-1和CTLA-4以“揭露”选定患者的潜在免疫功能。在相同的患者和对照中，将使用LuminexTM分析细胞因子/趋化因子的模式（Austin，TX）装置和特定珠粒组（Millipore，Billerica，MA）：IL-1 β，IL-1受体拮抗剂，IL-2，可溶性IL-2受体-α，IL-4，IL-5，IL-6，IL-7，IL-8，IL-10，IL-13，IL-15，IL-17，IFN-γ，IP-10，IFN-γ，MIP-1 α、MIP-1 β、MCP-1、GM-CSF、Eotaxin和TNF-α。将使用计算建模（包括主成分分析、分层聚类和网络发现方法）分析该免疫学特征数据;将表征免疫应答、HBeAg抗原和HBV DNA水平之间的关系。该项目的意义是继续JHPCC对HBRN儿科研究的富有成效的贡献，并提供有关年龄对HBV儿童免疫应答影响的新信息。

DESCRIPTION (provided by applicant): Hepatitis B virus infection in children is an important public health problem, with the majority of children acquiring HBV via maternal-fetal acquisition, putting them at high lifetime risk (~25 - 50%) of cirrhosis and/or hepatocellular carcinoma (HCC). HBe Antigen (HBeAg) positivity and persistently high levels of HBV DNA are independent risk factors for cirrhosis and HCC in adults. While little is known about the immunologic response to HBV DNA in children, we have observed that older children in the HBRN have higher rates of HBeAg clearance and lower levels of HBV DNA compared to younger subjects. Thus, careful investigation of T cell responses to HBV antigens and cytokine/chemokine patterns in children of different ages may reveal immunologic determinants associated with viral clearance and lead to improved antiviral therapies in the future. The overarching goals of this application are two-fold: 1) Continue recruiting and enrolling children t the pediatric HBRN studies and retaining the 156 (pediatric cohort) and 31 immune tolerant (IT) subjects already enrolled by the Johns Hopkins Pediatric Clinical Center (pediatric liver centers at Johns Hopkins, UTSW and University of Washington 2) Characterize T cell immune phenotypes and responses to HBV antigens and cytokine chemokine patterns in HBV-infected children in 2 age groups 5 - 10 years vs 10 -18 years compared to age and sex-matched non-infected controls and existing T cell data in adults. The immune phenotype of T cells will be characterized by staining (multi-color FACS.) In vitro blockade of inhibitory pathways such as PD-1 and CTLA-4 to 'unmask' the underlying immune function in select patients will be explored. In the same patients and controls, the patterns of cytokines/chemokines will be assayed using LuminexTM (Austin, TX) apparatus and specific beadsets (Millipore, Billerica, MA): IL-1beta, IL-1 receptor antagonist, IL-2, soluble IL-2 receptor-alpha, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-13, IL-15, IL-17, IFN-gamma, IP-10, MIG, MIP-1alpha, MIP-1beta, MCP-1, GM-CSF, Eotaxin, and TNF-alpha. This immunological profile data will be analyzed using computational modeling, including Principal Component Analysis, hierarchical clustering, and network discovery methods; relationships between immune responses, HBeAntigen, and HBV DNA levels will be characterized. The significance of this project is to continue the productive contributions of the JHPCC to the pediatric studies of the HBRN and to contribute novel information regarding the effects of age on immune responses of children with HBV.