Transplant EBV Disease: Pathogenesis and Immunotherapy

儿科实体器官移植中使用的免疫抑制疗法与EB病毒（EBV）驱动的淋巴组织增生性疾病的发展相关。（PTLD）几乎十分之一的儿科心脏移植（Tx）接受者在Tx后7年内会发展PTLD。这种并发症患者的长期结果令人失望。百分之九十的病例是由EBV驱动的，几乎所有的肿瘤都是受体B细胞来源的。大多数O Tx患者的病毒载量持续升高，我们对这些载量是如何建立或维持的没有清楚的了解，也没有清楚的了解持续的病毒载量对无症状携带者的危险。我们提出了一个病毒学分析的持续EBV感染的儿童心脏（H）和心脏/肺（H/L）的Tx受体， 匹兹堡儿童医院在这项研究中，我们计划使用定量PCR和免疫组化技术来表征高和低病毒载量的B细胞室，病毒感染细胞的克隆性程度，以及病毒启动子使用和基因表达的模式。通过使用现有的标本库（我们将在研究期间添加），将回顾性和前瞻性收集数据，以提供 导致装载机状态和PTLD的病毒感染过程的清晰图像。受损的T细胞免疫监视是慢性高病毒载量和PTLD进展的重要相关因素，并且关于免疫抑制Tx患者中残留应答细胞类型的频率和特异性知之甚少。初步工作表明，T细胞反应可能会偏离有益的Th 1表型，向不太有效的Th 2表型。使用HLA-tetramer和ELISPOT测定，我们将表征H和H/L Tx患者中抗EBV CD 8 T细胞反应的谱系和频率。尽管在这些患者的护理方面取得了一些进展，但总体上，EBV疾病患者，特别是PTLD患者的管理仍然极具挑战性。虽然许多人，如果不是 大多数患者将经历对免疫抑制减少的临床反应，这是以在该治疗操作期间发生叠加排斥的潜在代价来完成的。对于H或HtL Tx接受者，接受这种排斥风险必须了解排斥可能会导致心律失常和猝死。我们将开发EB病毒特异性CTL过继免疫治疗作为一种安全有效的替代方案 治疗小儿H和H/L Tx受体。将进行1期临床试验，以确定儿科胸部Tx接受者中难治性PTLD、复发性PTLD或症状性EBV疾病对使用树突状细胞针对特定EBV抗原产生的CTL输注的应答。

Immunosuppressive therapies used in pediatric solid organ transplantation are associated with the development of Epstein-Barr virus (EBV) driven lymphoproliferative disease. (PTLD) Almost one in 10 pediatric heart transplant (Tx) recipients will develop PTLD by 7 years after Tx. Long-term outcomes of patients with this complication have been disappointing. Ninety percent of cases are driven by EBV and almost all tumors are of recipient B cell origin. A majority ot Tx patients develop persistently elevated viral loads and we do not have a clear understanding of how these loads are established or maintained, or a clear picture of what dangers persistent viral loads represent to an asymptomatic carder. We propose a virologic analysis of persistent EBV infection in the pediatric heart (H) and heart/lung (H/L) Tx recipients at the Children's Hospital of Pittsburgh. For this study, we plan to use quantitative PCR and immunohistochemical techniques to characterize the high and low viral load in terms of the B cell compartments involved, the degree of clonality of the virus infected cells, and the patterns of viral promoter usage and gene expression. By using an existing specimen bank, to which we will add during the study, data will be collected retrospectively and prospectively to provide a clear picture of the course of virus infection that leads to the load carder state and PTLD. Impaired T cell immune surveillance is an important correlate in progressionto chronic high viral loads and PTLD, and little is known about the residual responder cell types in terms of their frequencies and specificities in immunosuppressed Tx patients. Preliminary work indicates that T cell responses may be skewed away from the beneficial Th1 phenotype towards the less effective Th2 phenotype. Using HLA-tetramer and ELISPOT assays we will characterize the repertoire and frequency of anti-EBV CD8 T cell responses in H and H/L Tx patients. The management of patients with EBV disease, in general, and PTLD in particular remains extremely challenging despite a number of advances in the care of these patients. While many, if not the majority of patients will experience a clinical response to reduction of immune suppression, this is done at the potential cost of developing superimposed rejection during thistherapeutic manipulation. For H or HtL Tx recipients, acceptance of this risk of rejection must come with the knowledge that rejection may present with dysrhythmia and sudden death. We will develop adoptive immunotherapy with EBV-specific CTLs as a safe and effective alternative therapy for pediatric H and H/L Tx recipients. A phase 1 clinical trial will be conducted to determine the response of fractory PTLD, relapsed PTLD, or symptomatic EBV disease in pediatric thoracic Tx recipients to infusions of CTLs raised against specific EBV antigens using dendritic cells.