Leukaemic stem cells (LSC) have been experimentally defined as the leukaemia‐propagating population and are thought to be the cellular reservoir of relapse in acute myeloid leukaemia (AML). Therefore, LSC measurements are warranted to facilitate accurate risk stratification. Previously, we published the composition of a one‐tube flow cytometric assay, characterised by the presence of 13 important membrane markers for LSC detection. Here we present the validation experiments of the assay in several large AML research centres, both in Europe and the United States. Variability within instruments and sample processing showed high correlations between different instruments (R_pearson > 0·91, P < 0·001). Multi‐centre testing introduced variation in reported LSC percentages but was found to be below the clinical relevant threshold. Clear gating protocols resulted in all laboratories being able to perform LSC assessment of the validation set. Participating centres were nearly unanimously able to distinguish LSC^high (>0·03% LSC) from LSC^low (<0·03% LSC) despite inter‐laboratory variation in reported LSC percentages. This study proves that the LSC assay is highly reproducible. These results together with the high prognostic impact of LSC load at diagnosis in AML patients render the one‐tube LSC assessment a good marker for future risk classification.

中文翻译：

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多中心环境下急性髓细胞白血病干细胞评估的适用性和可重复性。

白血病干细胞（LSC）在实验上已定义为传播白血病的人群，被认为是急性髓细胞性白血病（AML）复发的细胞储存库。因此，有必要对LSC进行测量以促进准确的风险分层。先前，我们发布了单管流式细胞仪检测的组成，其特征是存在用于LSC检测的13种重要膜标记物。在这里，我们介绍了在欧洲和美国的几个大型AML研究中心进行的测定验证实验。仪器内部和样品处理之间的变异性表明不同仪器之间具有高度相关性（R _pearson  > 0·91，P <0·001）。多中心测试引入了报告的LSC百分比变化，但发现低于临床相关阈值。清晰的门控协议使所有实验室都能够对验证集进行LSC评估。尽管实验室间报告的LSC百分比存在差异，但参与中心几乎能够将LSC^高（> 0·03％LSC）与LSC^低（<0·03％LSC）区分开。这项研究证明了LSC分析具有高度的可重复性。这些结果以及LSC负荷在AML患者诊断中对预后的高度影响，使得单管LSC评估成为未来风险分类的良好标志。