Accurate knowledge of expression patterns/levels of commonly used MRD markers in regenerative normal-B-cell-precursors (BCP) is highly desirable to distinguish leukemic-blasts from regenerative-BCP for multicolor flow cytometry (MFC)-based measurable residual disease (MRD) assessment in B-lymphoblastic leukemia (B-ALL). However, the data highlighting therapy-related immunophenotypic-shift in regenerative-BCPs is scarce and limited to small cohort. Herein, we report the in-depth evaluation of immunophenotypic shift in regenerative-BCPs from a large cohort of BALL-MRD samples. Ten-color MFC-MRD analysis was performed in pediatric-BALL at the end-of-induction (EOI), end-of-consolidation (EOC), and subsequent-follow-up (SFU) time-points. We studied normalized-mean fluorescent intensity (nMFI) and coefficient-of-variation of immunofluorescence (CVIF) of CD10, CD19, CD20, CD34, CD38, and CD45 expression in regenerative-BCP (early, BCP1 and late, BCP2) from 200 BALL-MRD samples, and compared them with BCP from 15 regenerating control (RC) TALL-MRD samples and 20 treatment-naïve bone-marrow control (TNSC) samples. Regenerative-BCP1 showed downregulation in CD10 and CD34 expression with increased CVIF and reduced nMFI (p < 0.001), upregulation of CD20 with increased nMFI (p = 0.014) and heterogeneous CD45 expression with increased CVIF (p < 0.001). Immunophenotypic shift was less pronounced in the BCP2 compared to BCP1 compartment with increased CVIF in all but CD45 (p < 0.05) and reduced nMFI only in CD45 expression (p = 0.005). Downregulation of CD10/CD34 and upregulation of CD20 was higher at EOI than EOC and SFU time-points (p < 0.001). Regenerative-BCPs are characterized by the significant immunophenotypic shift in commonly used B-ALL-MRD markers, especially CD10 and CD34 expression, as compared to treatment-naïve BCPs. Therefore, the templates/database for BMRD analysis must be developed using regenerative-BCP.

中文翻译：

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再生骨髓样本中 B 细胞前体的免疫表型转变：B 淋巴细胞白血病中可测量残留疾病评估的关键考虑因素

准确了解再生正常 B 细胞前体 (BCP) 中常用 MRD 标志物的表达模式/水平对于基于多色流式细胞术 (MFC) 的可测量残留病 (MRD) 区分白血病母细胞和再生 BCP 是非常可取的) 在 B 淋巴细胞白血病 (B-ALL) 中的评估。然而，强调再生 BCP 中与治疗相关的免疫表型转变的数据很少且仅限于小群体。在这里，我们报告了对来自大量 BALL-MRD 样本的再生 BCP 中免疫表型转变的深入评估。在诱导结束 (EOI)、巩固结束 (EOC) 和后续随访 (SFU) 时间点对儿科-BALL 进行十色 MFC-MRD 分析。我们研究了从 200 年开始的再生 BCP（早期，BCP1 和晚期，BCP2）中 CD10、CD19、CD20、CD34、CD38 和 CD45 表达的标准化平均荧光强度 (nMFI) 和免疫荧光变异系数 (CVIF) BALL-MRD 样本，并将它们与来自 15 个再生对照 (RC) TALL-MRD 样本和 20 个未经治疗的骨髓对照 (TNSC) 样本的 BCP 进行比较。Regenerative-BCP1 显示 CD10 和 CD34 表达下调，CVIF 增加，nMFI 降低。p  < 0.001），CD20 上调随 nMFI 增加（p  = 0.014）和异质 CD45 表达随 CVIF 增加（p  < 0.001）。与 BCP1 隔室相比，BCP2 中的免疫表型转变不太明显，除 CD45 外，所有部位的 CVIF 均增加（p  < 0.05），仅在 CD45 表达中 nMFI 降低（p  = 0.005）。EOI 时 CD10/CD34 的下调和 CD20 的上调高于 EOC 和 SFU 时间点（p < 0.001)。与未经治疗的 BCP 相比，再生 BCP 的特点是常用 B-ALL-MRD 标志物的免疫表型发生显着变化，尤其是 CD10 和 CD34 表达。因此，必须使用再生 BCP 开发用于 BMRD 分析的模板/数据库。