With the continued poor outcome of relapsed acute lymphoblastic leukemia (ALL), new patient-specific approaches for disease progression monitoring and therapeutic intervention are urgently needed. Patient-derived xenografts (PDX) of primary ALL in immune-deficient mice have become a powerful tool for studying leukemia biology and therapy response. In PDX mice, the immunophenotype of the patient's leukemia is commonly believed to be stably propagated. In patients, however, the surface marker expression profile of the leukemic population often displays poorly understood immunophenotypic shifts during chemotherapy and ALL progression. We therefore developed a translational flow cytometry platform to study whether the patient-specific immunophenotype is faithfully recapitulated in PDX mice. To enable valid assessment of immunophenotypic stability and subpopulation complexity of the patient's leukemia after xenotransplantation, we comprehensively immunophenotyped diagnostic B-ALL from children and their matched PDX using identical, clinically standardized flow protocols and instrument settings. This cross-standardized approach ensured longitudinal stability and cross-platform comparability of marker expression intensity at high phenotyping depth. This analysis revealed readily detectable changes to the patient leukemia-associated immunophenotype (LAIP) after xenotransplantation. To further investigate the mechanism underlying these complex immunophenotypic shifts, we applied an integrated analytical approach that combined clinical phenotyping depth and high analytical sensitivity with unbiased high-dimensional algorithm-based analysis. This high-resolution analysis revealed that xenotransplantation achieves patient-specific propagation of phenotypically stable B-ALL subpopulations and that the immunophenotypic shifts observed at the level of bulk leukemia were consistent with changes in underlying subpopulation abundance. By incorporating the immunophenotypic complexity of leukemic populations, this novel cross-standardized analytical platform could greatly expand the utility of PDX for investigating ALL progression biology and assessing therapies directed at eliminating relapse-driving leukemic subpopulations.

中文翻译：

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用于评估前体 B 细胞急性淋巴细胞白血病 (B-ALL) 异种移植物表型稳定性的交叉标准化流式细胞术平台

随着复发性急性淋巴细胞白血病 (ALL) 的持续不良结果，迫切需要新的针对患者的疾病进展监测和治疗干预方法。免疫缺陷小鼠原发性 ALL 的患者来源异种移植物 (PDX) 已成为研究白血病生物学和治疗反应的有力工具。在 PDX 小鼠中，患者白血病的免疫表型通常被认为是稳定传播的。然而，在患者中，白血病人群的表面标志物表达谱通常在化疗和 ALL 进展期间显示出人们知之甚少的免疫表型变化。因此，我们开发了一个平移流式细胞仪平台来研究患者特异性免疫表型是否在 PDX 小鼠中得到忠实再现。为了有效评估异种移植后患者白血病的免疫表型稳定性和亚群复杂性，我们使用相同的临床标准化流程协议和仪器设置对来自儿童及其匹配的 PDX 的诊断性 B-ALL 进行了全面的免疫表型诊断。这种交叉标准化的方法确保了高表型深度下标记表达强度的纵向稳定性和跨平台可比性。该分析揭示了异种移植后患者白血病相关免疫表型 (LAIP) 的可检测变化。为了进一步研究这些复杂的免疫表型变化背后的机制，我们应用了一种综合分析方法，将临床表型深度和高分析灵敏度与基于无偏高维算法的分析相结合。这项高分辨率分析表明，异种移植实现了表型稳定的 B-ALL 亚群的患者特异性传播，并且在大块白血病水平观察到的免疫表型变化与潜在亚群丰度的变化一致。通过结合白血病人群的免疫表型复杂性，这种新型的交叉标准化分析平台可以极大地扩展 PDX 在研究 ALL 进展生物学和评估旨在消除复发驱动的白血病亚群的疗法方面的效用。这项高分辨率分析表明，异种移植实现了表型稳定的 B-ALL 亚群的患者特异性传播，并且在大块白血病水平观察到的免疫表型变化与潜在亚群丰度的变化一致。通过结合白血病人群的免疫表型复杂性，这种新型的交叉标准化分析平台可以极大地扩展 PDX 在研究 ALL 进展生物学和评估旨在消除复发驱动的白血病亚群的疗法方面的效用。这项高分辨率分析表明，异种移植实现了表型稳定的 B-ALL 亚群的患者特异性传播，并且在大块白血病水平观察到的免疫表型变化与潜在亚群丰度的变化一致。通过结合白血病人群的免疫表型复杂性，这种新型的交叉标准化分析平台可以极大地扩展 PDX 在研究 ALL 进展生物学和评估旨在消除复发驱动的白血病亚群的疗法方面的效用。