BACKGROUND Flow-cytometric minimal residual disease (FC-MRD) monitoring is a well-established risk-stratification factor in B-lymphoblastic leukemia/lymphoma (-B-ALL) and is being considered as a basis for deintensification or escalation in treatment protocols. However, currently practiced standard FC-MRD has limited sensitivity (up to 0.01%) and higher false MRD-negative rate. Hence, a highly sensitive, widely applicable, and easily reproducible FC-MRD assay is needed, which can provide a reliable basis for therapeutic modifications. METHODS A 10-color high-event analysis FC-MRD assay was studied for the evaluation of MRD status at postinduction, (PI; day-35), postconsolidation, (PC; day-78), and subsequent follow-up time-points (SFU) in bone marrow samples from pediatric B-ALL. RESULTS One-thousand MRD samples (PI-62.2%; PC-26.5%; and SFU-11.3%) from 622 childhood B-ALL patients were studied. High-event analysis was performed with median 4,452,000 events (range, 839,000 to 8,866,000 events) and >4 million events in 71% samples. MRD was measurable in 43.2% of PI-samples, in 29.4% PC-samples, and in 32.7% SFU-samples. To simulate comparison with standard FC-MRD, we reanalyzed MRD results gating only first 500,000 and first 1000,000 events in 122 PI-MRD positive samples with MRD levels <0.02%. Of these samples gated for 500,000 events and 1000,000 events, 32% and 21.3% were found to be falsely MRD-negative, respectively. CONCLUSIONS We report an easily reproducible high-sensitivity 10-color FC-MRD assay with the sensitivity of 2-in-106 (0.0002%). It allowed the detection of low-level MRD in samples, which could have been reported negative using the standard FC-MRD with limited event analysis. Thus, this high-sensitivity MRD-methodology can provide a reliable basis for therapeutic modifications in B-ALL. © 2019 International Clinical Cytometry Society.

中文翻译：

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B淋巴细胞性白血病/淋巴瘤的高灵敏度10色流式细胞术最小残留病分析可轻松实现2合106的灵敏度，优于标准最小残留病分析：一项针对622例患者的研究。

背景技术流式细胞术最小残留疾病（FC-MRD）监测是B淋巴细胞白血病/淋巴瘤（-B-ALL）中公认的风险分层因素，被认为是治疗方案中血肿减轻或升级的基础。但是，当前实践的标准FC-MRD的灵敏度有限（高达0.01％），并且较高的错误MRD阴性率。因此，需要高度灵敏，广泛适用并且易于再现的FC-MRD测定法，其可以为治疗修饰提供可靠的基础。方法研究了一种10色高事件分析FC-MRD分析方法，用于评估诱导后（PI；第35天），合并后（PC：第78天）及后续随访时间点的MRD状态（SFU）来自小儿B-ALL的骨髓样本。结果一千个MRD样本（PI-62.2％; PC-26.5％;和SFU-11。对622名儿童期B-ALL患者进行了3％的研究。高事件分析在71％的样本中进行了中位数4,452,000个事件（范围从839,000到8,866,000个事件）和> 400万个事件。在43.2％的PI样品，29.4％的PC样品和32.7％的SFU样品中，MRD可测量。为了模拟与标准FC-MRD的比较，我们对MRD结果进行了重新分析，仅对122个PI-MRD阳性样品中MRD水平<0.02％的前500,000个事件和前1000,000个事件进行了门。在针对500,000个事件和1000,000个事件的门控样本中，分别发现32％和21.3％的MRD阴性。结论我们报告了一种易于重现的高灵敏度10色FC-MRD检测方法，灵敏度为2-in-106（0.0002％）。它可以检测样品中的低水平MRD，如果使用标准的FC-MRD和受限事件分析，可能会报告为阴性。因此，这种高灵敏度的MRD方法可以为B-ALL中的治疗修饰提供可靠的基础。©2019国际临床细胞计量学会。