CLINICAL SIGNIFICANCE OF MINIMAL RESIDUAL DISEASE IN CHILDHOOD ALL

越来越多的证据表明，根除最小残留 可检测到的白血病细胞是治愈所必需的。相当大的努力已经 因此，在过去的十年里，我们开发了敏感的方法来 检测患者体内这些微小的残留白血病细胞。聚合酶 非随机染色体易位的链式反应扩增 允许灵敏地检测白血病。然而，大多数人 急性淋巴细胞性白血病(ALL)的儿童没有表现出这样的症状 非随机染色体易位，可供选择的策略是 检测微小残留病(MRD)所必需的。在B细胞和T细胞中 通常都是免疫球蛋白(Ig)或T细胞重排 受体(TCR)基因或两者，及其克隆后代具有相同的 重新编排。这种独特的重新安排提供了一个目标 MRD的扩增和检测。此外，竞争性的聚合酶链式反应分析可以 用于定量评估患者体内的肿瘤负担。聚合酶链反应 免疫球蛋白重链基因和TCR增量基因的分析将是 用于扩增白血病特异性抗原受体。序列分析 将使我们能够设计特定的结合点 检测和定量白血病负荷的寡核苷酸探针 所有人都是孩子。这一提议的基本假设是一个快速的 诱导和强化期间白血病负担的减轻 预测了更高的治愈率，并消除了可检测到的 白血病细胞是治愈所必需的。为此，我们提出了两个具体的 目标。第一：检测、量化和确定临床 MRD在儿童ALL中的意义，以评估白血病负担 提出并确定减少的幅度是否 项目4和项目4概述的诱导治疗期间的白血病负担 在随后的治疗中，顺序地预测结果。为了实现这一目标，我们 还应比较MRD检测的临床实用价值 并评估外周血和骨髓的检测是否 寡克隆性疾病或克隆性进化对预后有意义。 第二：评估儿童MRD检测的临床意义 复发后，用定量聚合酶链式反应分析评估白血病负担 并将其与临床结果相关联，并确定是否 自体骨髓移植后根治MRD是必要的 移植(ABMT)。在这一目标中，我们将确定临床 急性白血病时患者白血病负担的临床意义 ABMT后自体骨中白血病细胞的PCR检测 免疫净化前后骨髓或外周血干细胞 与糟糕的结局有关。还将进行聚合酶链式反应分析以 评估项目中概述的新治疗策略对MRD的影响 1.我们的总体目标是评估检测的临床意义 和MRD的量化，使我们能够识别高危儿童 后来的失败，同样重要的是，识别这些孩子 他们可能已经被治愈，然后可以免于随后的中毒 心理治疗。通过这种方法，我们应该能够为每个人量身定做治疗 基于随时间推移的风险，从而最大化 治疗指数。

Increasing evidence suggests that the eradication of minimal residual detectable leukemia cells is necessary for cure. Considerable effort has therefore been made over the past decade to develop sensitive methods to detect these minimal residual leukemic cells in the patient. Polymerase chain reaction (PCR) amplification of non-random chromosome translocations permits sensitive detection of leukemia. However, the majority of children with acute lymphoblastic leukemia (ALL) do not demonstrate such non-random chromosomal translocations, and alternative strategies are necessary to detect minimal residual disease (MRD). In both B and T cell ALL there is usually rearrangement of immunoglobulin (Ig) or T cell receptor (TCR) genes or both, and their clonal progeny bear the identical rearrangement. This unique rearrangement provides a target for amplification and detection of MRD. Moreover, competitive PCR assays can be used to assess quantitatively the tumor burden within the patient. PCR analysis at both the Ig heavy chain locus and the TCR delta locus will be used to amplify the leukemia specific antigen receptor. Sequence analysis of the PCR product will enable us to design junctional specific oligonucleotide probes to detect and quantitate leukemic burden in children with ALL. The basic hypotheses of this proposal are that a rapid reduction in the leukemic burden during induction and intensification predicts for a higher cure rate and that the elimination of detectable leukemia cells is necessary for cure. To this end we propose two specific aims. FIRST: to detect, quantitate and determine the clinical significance of MRD in childhood ALL, to assess the leukemic burden at presentation and to determine whether the magnitude of reduction of leukemic burden during induction therapy as outlined in PROJECT 4 and serially throughout subsequent therapy predicts outcome. In this aim we shall also compare the clinical utility of the detection of MRD in peripheral blood and bone marrow and assess whether the detection of oligoclonal disease or clonal evolution has prognostic significance. SECOND: to assess the clinical significance of MRD detection in children after relapse, to assess leukemic burden using quantitative PCR analysis and to correlate this with clinical outcome, and to determine whether the eradication of MRD is necessary for cure after autologous bone marrow transplantation (ABMT). In this aim we shall determine the clinical significance of the leukemic burden in the patient at the time of and after ABMT and whether PCR detection of leukemia cells in autologous bone marrow or peripheral blood stem cells before and after immunologic purging is associated with poor outcome. PCR analysis will also be performed to assess the impact on MRD of novel treatment strategies outlined in PROJECT 1. Our overall goal is to assess the clinical significance of detection and quantification of MRD to enable us to identify children at high risk of subsequent failure, and just as importantly, to identify those children who may already be cured who could then be spared subsequent toxic therapy. With this approach we should be able to tailor treatment to each individual child based on the risk over time and thereby maximize the therapeutic index.