CD49f 是 B 细胞急性淋巴细胞白血病恶性淋巴细胞上存在的一种粘附分子；它与不良预后相关。 CD49f表达已被提议作为可测量残留病（MRD）标记物的标记，但该标记物尚未在临床实践中实施。在本研究中，我们使用流式细胞术检测配对骨髓和脑脊液中白血病母细胞的CD49f表达诊断时的液体样本和治疗第15天的骨髓。诊断时，93%的骨髓和100%的脑脊液淋巴母细胞表达CD49f。 CD49f 表达强度在治疗期间显着增加 (P < .001)。在 MRD 阴性的治疗结束样本中，只有一小部分血细胞表达 CD49f。有趣的是，CD49f 表达的强度在不同的复发性遗传异常组之间有所不同。 ETV6::RUNX1融合和ETV6::RUNX1与高超二倍体组结合与表达增加相关，而Philadelphia样组则表现出低CD49f表达。诊断时 CD49f 表达较低，预示治疗第 15 天的 MRD 率较低。我们得出结论，CD49f 可用作 B 细胞急性淋巴细胞白血病的 MRD 标记物和可能的预后因素。© 美国临床病理学会，2024。

CD49f is an adhesion molecule present on malignant lymphoblasts in B-cell acute lymphoblastic leukemia; it is associated with a poor prognosis. CD49f expression has been proposed as a marker for measurable residual disease (MRD) marker, but this marker has yet to be implemented in clinical practice.In this study, we used flow cytometry to detect CD49f expression by leukemic blasts in paired bone marrow and cerebrospinal fluid samples at diagnosis and bone marrow at day 15 of treatment.At diagnosis, 93% of bone marrow and 100% of cerebrospinal fluid lymphoblasts expressed CD49f. The intensity of CD49f expression statistically significantly increased during treatment (P < .001). In MRD-negative end-of-treatment samples, only a small population of hematogones expressed CD49f. Interestingly, the intensity of CD49f expression varied among the different groups of recurrent genetic abnormalities. The ETV6::RUNX1 fusion and ETV6::RUNX1 combined with the high hyperdiploid group were associated with increased expression, whereas the Philadelphia-like group showed low CD49f expression. The lower CD49f expression at diagnosis predicted a lower MRD rate at day 15 of treatment.We concluded that CD49f can be used as an MRD marker and possible prognostic factor in B-cell acute lymphoblastic leukemia.© American Society for Clinical Pathology, 2024.