Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain.
URSalud Laboratory, Hospital Universitario Infanta Sofia, 28702 San Sebastián de los Reyes, Spain.
Int J Mol Sci. 2024 Nov 5;25(22):11898. doi: 10.3390/ijms252211898.
Flow cytometry plays a fundamental role in the diagnosis of leukemias and lymphomas, as well as in the follow-up and evaluation of minimally measurable disease after treatment. In some instances, such as in the case of acute promyelocytic leukemia (APL), rapid diagnosis is required to avoid death due to serious blood clotting or bleeding complications. Given that promyelocytes do not express the glycophosphatidylinositol (GPI)-anchored protein CD16 and that deficient CD16 expression is a feature of some CD16 polymorphisms and paroxysmal nocturnal hemoglobinuria (PNH), we included the GPI anchor probe FLAER aerolysin in the APL flow cytometry probe panel. Initial tests showed that FLAER binding was absent in pathological promyelocytes from APL patients but was consistently detected with high intensity in healthy promyelocytes from control bone marrow. FLAER binding was studied in 71 hematologic malignancies. Appropriate control cells were obtained from 16 bone marrow samples from patients with idiopathic thrombocytopenic purpura and non-infiltrated non-Hodgkin's lymphoma. Compared with the positive FLAER signal in promyelocytes from healthy bone marrow, malignant promyelocytes from APL patients showed weak or negative FLAER binding. The FLAER signal in APL promyelocytes was also lower than that in control myeloid progenitors and precursors from patients with other forms of acute myeloid leukemia (AML), B-cell acute lymphoblastic leukemia, or myelodysplastic syndrome. Minimal measurable disease studies performed in APL patients after treatment found normal promyelocyte expression when minimal measurable disease was negative and FLAER-negative promyelocytes when disease relapse was detected. The inclusion of FLAER in the flow cytometry diagnosis and follow-up of APL could be very helpful. Decreased FLAER binding was found in all cases of APL, confirmed by the detection of the PML-RARA fusion transcript and, to a lesser extent, in the other AMLs studied. This study also revealed FLAER differences in other acute leukemias and even between different precursors (myeloid and lymphoid) from healthy controls. However, the reason for FLAER's non-binding to the malignant precursors of these leukemias remains unknown, and future studies should explore the possible relation with an immune escape phenomenon in these leukemias.
流式细胞术在白血病和淋巴瘤的诊断中起着重要作用，也可用于治疗后微量残留病的随访和评估。在某些情况下，例如急性早幼粒细胞白血病 (APL)，需要快速诊断以避免因严重的凝血或出血并发症而导致死亡。鉴于早幼粒细胞不表达糖基磷脂酰肌醇 (GPI)-锚定蛋白 CD16，并且 CD16 表达缺失是某些 CD16 多态性和阵发性夜间血红蛋白尿 (PNH) 的特征，我们在 APL 流式细胞术探针组中包含了 GPI 锚定探针 FLAER 气溶素。初步测试表明，APL 患者的病理性早幼粒细胞中缺乏 FLAER 结合，但在健康对照骨髓中的早幼粒细胞中始终以高强度检测到。在 71 种血液恶性肿瘤中研究了 FLAER 结合。从 16 例特发性血小板减少性紫癜和非浸润性非霍奇金淋巴瘤患者的骨髓样本中获得了适当的对照细胞。与健康骨髓中早幼粒细胞的阳性 FLAER 信号相比，APL 患者的恶性早幼粒细胞显示出弱或阴性的 FLAER 结合。APL 早幼粒细胞中的 FLAER 信号也低于其他形式的急性髓系白血病 (AML)、B 细胞急性淋巴细胞白血病或骨髓增生异常综合征患者的对照髓系祖细胞和前体细胞。在治疗后 APL 患者进行的微量残留病研究中，当微量残留病为阴性且疾病复发时检测到 FLAER 阴性早幼粒细胞时，发现正常的早幼粒细胞表达。FLAER 在 APL 的流式细胞术诊断和随访中的加入可能非常有帮助。通过检测 PML-RARA 融合转录本证实，所有 APL 病例均发现 FLAER 结合减少，在所研究的其他 AML 中程度较轻。这项研究还揭示了其他急性白血病甚至健康对照中不同前体细胞 (髓系和淋巴系) 之间的 FLAER 差异。然而，FLAER 与这些白血病恶性前体不结合的原因尚不清楚，未来的研究应探讨在这些白血病中与免疫逃避现象的可能关系。
