羟基脲 (HU) 经常用于慢性粒细胞白血病 (CML) 的早期阶段，以在酪氨酸激酶抑制剂 (TKI) 治疗之前实现细胞减灭。然而，它对 CML 干细胞和祖细胞 (SPC) 的影响仍然很大程度上未知。本研究利用来自慢性期 CML 患者的 60,000 个 CD14-CD34 细胞中 596 个基因和 51 个表面蛋白的靶向蛋白质转录组表达数据来确定短期 HU 治疗（4-19 天）对 CML SPC 的影响。外周血和骨髓样本取自 17 名符合短期 HU 治疗条件的 CML 患者（HU 前后各 3 名患者；HU 前 7 名患者；HU 后 7 名患者），并进行单细胞 CITE-seq 和/或流式细胞术分析。分析显示，HU 治疗后，血液和骨髓中表达血红蛋白（HBA1、HBA2、HBB）的红系祖细胞频率增加。此外，具有 S/G2/M 期相关基因和蛋白质表达的细胞亚群积累，可能代表细胞在细胞周期中停滞或缓慢进展。在最不成熟的白血病干细胞 (LSC) 中已经观察到 HU 后 S/G2/M 期细胞频率增加，并且 S/G2/M 期 LSC 比例高的患者对 TKI 治疗反应较差。我们得出的结论是，短期 HU 治疗需要红系祖细胞的分化，并改变 CML 中 LSC 的特征。结果表明，对 CML 中 LSC 和祖细胞群体的研究应考虑初始 HU 治疗的影响。

Hydroxyurea (HU) is frequently used in the early phase of chronic myeloid leukemia (CML) to achieve cytoreduction prior to tyrosine kinase inhibitor (TKI) therapy. However, its impact on CML stem and progenitor cells (SPC) remains largely unknown. This study utilized targeted proteo-transcriptomic expression data on 596 genes and 51 surface proteins in 60,000 CD14-CD34+ cells from chronic phase CML patients to determine effects of shortterm HU treatment (4-19 days) on CML SPC. Peripheral blood and bone marrow samples were obtained from 17 CML patients eligible for short-term HU treatment (three patients before and after HU; seven patients before HU; and seven patients after HU) and subjected to single-cell CITE-seq and/or flow cytometry analysis. The analysis revealed enhanced frequencies of hemoglobin-expressing (HBA1, HBA2, HBB) erythroid progenitor cells in blood and bone marrow following HU treatment. In addition, there was an accumulation of cell subsets with S/G2/M phase-related gene and protein expression, likely representing cells arrested in, or progressing slowly through, the cell cycle. The increased frequency of cells in S/G2/M phase after HU was observed already among the most immature leukemic stem cells (LSC), and patients with a high fraction of LSC in the S/G2/M phase showed poor responsiveness to TKI treatment. We conclude that short-term HU treatment entails differentiation of erythroid progenitor cells and alters the characteristics of LSC in CML. The results imply that studies of LSC and progenitor populations in CML should take effects of initial HU therapy into account.