Defining the scope and clinical impact of donor CHIP after allogeneic HCT

项目总结 异基因造血干细胞移植(HSCT)涉及移植健康供者的造血 包括造血干细胞和成熟免疫效应细胞在内的细胞移植给高危受者 恶性血液病。造血干细胞移植的成功从根本上取决于正常供者的植入- 衍生的造血术。移植物功能不全会导致一系列影响受者的并发症 结果，包括疾病复发、移植物抗宿主病和感染。在初步研究中，我们 发现克隆性造血受限的健康干细胞捐赠者，其标志是经典性基因突变 髓系恶性肿瘤的遗传驱动因素，即异常克隆植入移植受者体内，经历了 选择性扩张，并与造血功能异常有关。虽然罕见的患者会发展成 供体细胞白血病潜伏期长后，我们的数据提示供体移植的克隆非恶性结果 造血功能障碍或移植物抗宿主病可能更为常见，可能 在移植后表现得更早，从而大大增加了移植相关的发病率。我们 不确定潜能克隆性造血(CHIP)的存在是年龄无关的假说 移植物受损对受者预后产生负面影响的供者造血适合性预测因子 功能。这一建议在很大程度上结合了互补的遗传、功能和转录本方法 干细胞供受者对队列，以确定供体芯片对异基因造血干细胞移植结局的影响。具体而言 目的1.检测1911例异基因干细胞捐献者CHIP基因频率及其临床意义 40岁及以上(发现队列，n=1189；外部验证队列，n=722)。为了实现这一目标， 我们开发并验证了一种用于供体芯片鉴定的高灵敏测序平台 样品的灵敏度是标准下一代测序模式的50倍。这项工作将 与特定目标2密切相关，我们将重点关注具有克隆突变的捐赠者子集，以定义 克隆干细胞植入的效率和谱系潜力，以及克隆的遗传进化。 最后，在特定的目标3中，我们将剖析供体芯片对移植免疫功能的影响。 受者，测试干细胞克隆可以扰乱炎性细胞因子的产生和适当 通过对成熟免疫细胞亚群的克隆性贡献恢复免疫活性。总而言之，建议的 研究可能定义异基因造血干细胞移植中供者归因风险的新范式，并提供对 克隆优势的生物学机制及微环境对克隆进化的影响。

PROJECT SUMMARY Allogeneic hematopoietic stem cell transplantation (HSCT) involves the transfer of healthy donor hematopoietic cells, including hematopoietic stem cells and mature immune effector cells, to recipients with high-risk hematologic malignancies. The success of HSCT is fundamentally dependent on engraftment of normal donor- derived hematopoiesis. Inadequate graft function can cause a range of complications that impact recipient outcomes, including disease relapse, graft versus host disease, and infection. In preliminary studies, we identified healthy stem cell donors with clonally restricted hematopoiesis, marked by mutations in canonical genetic drivers of myeloid malignancies, where the aberrant clone engrafted in a transplant recipient, underwent selective expansion, and was associated with abnormal hematopoietic function. While rare patients developed donor cell leukemia after long latency, our data suggest that non-malignant outcomes of donor-engrafted clonal hematopoiesis, such as hematopoietic dysfunction or graft versus host disease may be more common and may manifest earlier after transplantation, thereby contributing significantly to transplant-related morbidity. We hypothesize that the presence of clonal hematopoiesis of indeterminate potential (CHIP) is an age-independent predictor of donor hematopoietic fitness that negatively impacts recipient outcome by causing impaired graft function. This proposal combines complementary genetic, functional, and transcriptomic approaches in a large cohort of stem cell donor-recipient pairs to define the impact of donor CHIP on allo HSCT outcomes. In Specific Aim 1, we will determine the frequency and clinical significance of CHIP in a 1911 allogeneic stem cell donors 40 years of age and older (discovery cohort,n=1189; external validation cohort, n=722). To complete this aim, we have developed and validated a highly sensitive sequencing platform for identification of CHIP in donor samples, with >50-fold greater sensitivity than standard next generation sequencing modalities. This work will be closely linked to Specific Aim 2, where we will focus on the subset of donors with clonal mutations to define the efficiency and lineage potential of clonal stem cell engraftment, and the genetic evolution of clones over time. Finally, in Specific Aim 3 we will dissect the functional impact of donor CHIP on immune function in transplant recipients, testing the hypothesis that stem cell clones can perturb inflammatory cytokine production and proper recovery of immune activity via their clonal contribution to mature immune cell subsets. Together, the proposed studies may define a new paradigm of donor-attributable risk in allogeneic HSCT and provide insights into biological mechanisms of clonal dominance and the influence of microenvironmental context on clonal evolution.