Department of Laboratory Medicine and Pathology, University of Washington, Seattle.
Am J Clin Pathol. 2021 Jan 4;155(1):38-54. doi: 10.1093/ajcp/aqaa242.
Assessment for minimal/measurable residual disease (MRD) is a powerful prognostic factor in B lymphoblastic leukemia/lymphoma (B-LL/L) that is quickly becoming standard of care in assessing patients with B-LL/L posttherapy. MRD can be assessed using methodologies including flow cytometry and molecular genetics, with the former being rapid, relatively inexpensive, and widely applicable in many hematopathology/flow cytometry laboratories.
This article presents an approach to MRD detection in B-LL/L by flow cytometry through case presentations with illustration of several potential pitfalls. We review normal maturation patterns, antigens used for assessment, flow panels that can be utilized, considerations to be made during therapy, and clinical impact. The benefits and drawbacks when using the "different from normal" and "leukemia associated phenotype" approaches are considered.
Evaluation for MRD in B-LL/L by flow cytometry relies on a knowledge of normal immunophenotypic patterns associated with B-cell maturation in states of rest and marrow regeneration so that one can identify patterns of antigen expression that differentiate abnormal, leukemic populations from regenerating hematogones or B-cell precursors. The nature of therapy can affect normal patterns, a phenomenon especially important to take into consideration given the increased use of targeted therapies in the treatment of B-LL/L.
Flow cytometry is widely available in many laboratories and is a cost-effective way to evaluate for B-LL/L MRD. However, panel validation and interpreter education are crucial for accurate assessment.
微小残留病（MRD）评估是 B 淋巴母细胞白血病/淋巴瘤（B-LL/L）的强有力预后因素，在评估 B-LL/L 患者治疗后情况时，它迅速成为评估的标准。MRD 可通过包括流式细胞术和分子遗传学在内的方法进行评估，前者快速、相对便宜且在许多血液病理学/流式细胞术实验室中广泛适用。
本文通过病例介绍展示了通过流式细胞术检测 B-LL/L 中 MRD 的方法，同时说明了几个潜在的陷阱。我们回顾了正常成熟模式、用于评估的抗原、可利用的流式细胞术面板、治疗期间需要考虑的因素以及临床影响。考虑了使用“不同于正常”和“白血病相关表型”方法的优缺点。
通过流式细胞术评估 B-LL/L 中的 MRD 依赖于对静止和骨髓再生状态下 B 细胞成熟相关免疫表型模式的了解，以便能够识别区分异常、白血病群体与再生造血细胞或 B 细胞前体的抗原表达模式。治疗的性质会影响正常模式，鉴于在 B-LL/L 的治疗中越来越多地使用靶向治疗，这一现象尤其需要考虑。
流式细胞术在许多实验室中广泛可用，是评估 B-LL/L MRD 的一种具有成本效益的方法。然而，面板验证和解释器教育对于准确评估至关重要。
