Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Cytometry B Clin Cytom. 2022 Jul;102(4):283-291. doi: 10.1002/cyto.b.22085. Epub 2022 Jun 18.
Prompt diagnosis of acute promyelocytic leukemia (APL) is critical for patient care. In this study, we aimed to characterize the immunophenotype of APL and explore immunophenotypic difference between APL and its mimics using flow cytometric analysis.
Eighty-five cases were collected, including 47 APL, 26 NPM1-mutated acute myeloid leukemia (AML) and 12 KMT2A-rearranged AML with an APL-like immunophenotype. Immunophenotypes were analyzed using flow cytometric analysis.
APL showed four distinct patterns (designated a-d) based on CD45/SSC plots. Blasts in patterns a-c showed high side scatter, whereas blasts in pattern d had low side scatter and were located in the traditional blast gate. Compared with patterns a-c, pattern d of APL (APL-D) was more often positive for CD2 (p = 0.0005) and CD34 (p = 0.0002) in blasts. All NPM1-mutated AML and KMT2A-rearranged AML cases with an APL-like immunophenotype had blasts in the traditional blast gate on CD45/SSC, mimicking APL-D. In comparison, uniform CD13 and positive CD64 were seen in 100% (n = 13) APL-D cases and in only 2 of 26 (8%) NPM1-mutated AML cases (p < 0.0001). In addition, APL-D cases were more likely to be positive for CD2 and/or CD34 than NPM1-mutated AML (p < 0.0001 and p = 0.0007, respectively). In comparison with APL-D, KMT2A-rearranged AML cases were less often positive for myeloperoxidase (MPO) (p = 0.001), with none being strongly positive. Similar to NPM1-mutated AML and different from APL-D, KMT2A-rearranged AML cases were rarely positive for CD34 and all negative for CD2.
APL and its immunophenotypic mimics share some immunophenotypic similarities but can be distinguished by CD2, CD13, CD34, CD64, and MPO.
急性早幼粒细胞白血病（APL）的及时诊断对患者的治疗至关重要。本研究旨在通过流式细胞术分析，对 APL 的免疫表型进行特征描述，并探讨 APL 与其模拟物之间的免疫表型差异。
共收集了 85 例病例，包括 47 例 APL、26 例 NPM1 突变型急性髓系白血病（AML）和 12 例具有 APL 样免疫表型的 KMT2A 重排 AML。采用流式细胞术分析免疫表型。
根据 CD45/SSC 图谱，APL 显示出四种不同的模式（分别命名为 a-d）。模式 a-c 的blasts 具有高侧向散射，而模式 d 的blasts 具有低侧向散射，位于传统的 blast 门内。与模式 a-c 相比，APL 的模式 d（APL-D）的blasts 中 CD2（p=0.0005）和 CD34（p=0.0002）的阳性率更高。所有具有 APL 样免疫表型的 NPM1 突变型 AML 和 KMT2A 重排 AML 病例的blasts 均位于 CD45/SSC 的传统 blast 门内，与 APL-D 相似。相比之下，100%（n=13）的 APL-D 病例均表现为均匀的 CD13 阳性和 CD64 阳性，而仅有 2 例（8%）NPM1 突变型 AML 病例表现为阳性（p<0.0001）。此外，APL-D 病例更可能表现为 CD2 和/或 CD34 阳性，而非 NPM1 突变型 AML（p<0.0001 和 p=0.0007）。与 APL-D 相比，KMT2A 重排 AML 病例对髓过氧化物酶（MPO）的阳性率较低（p=0.001），且无一例呈强阳性。与 NPM1 突变型 AML 相似，而与 APL-D 不同，KMT2A 重排 AML 病例很少表达 CD34，且均为 CD2 阴性。
APL 及其免疫表型模拟物具有一些免疫表型相似性，但可通过 CD2、CD13、CD34、CD64 和 MPO 进行区分。
