Division of Hematopathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
Cytometry B Clin Cytom. 2012 Mar;82(2):85-92. doi: 10.1002/cyto.b.20623. Epub 2011 Oct 26.
Flow cytometric immunophenotyping has an established role in the diagnosis and monitoring of B-lymphoblastic leukemia (B-LL). However, the search continues for an optimal reagent set that can identify leukemic blasts with specificity, reproducibility, and sensitivity, at any point during the course of the disease and in every specimen type.
This study evaluated the diagnostic utility of detecting the intracytoplasmic antigens zeta-associated protein (ZAP-70) and Bcl-2 in the distinction between the leukemic blasts of B-LL and hematogones.
In comparison with hematogones in reference specimens, significantly higher levels of Bcl-2 were identified in 21 of 23 (91%) B-LL. In particular, Bcl-2 expression was consistently higher in leukemic blasts with bright intensity CD10 expression than the equivalent most immature (CD10 bright intensity) hematogones. As previously reported, Bcl-2 expression was lower in B-LL with BCR-ABL1 gene rearrangement, but the fluorescence intensity of this group of specimens was still significantly higher than that seen for hematogones. In contrast, ZAP-70 was expressed at significantly higher levels in only 7 of 23 (30%) B-LL and demonstrated other findings that might limit clinical utility, including differences in the level of ZAP-70 expression during therapy and between blasts in the peripheral blood and bone marrow.
Bcl-2 over-expression provides a useful tool for the distinction between B-LL and hematogones. In contrast, although further optimization of the ZAP-70 assay might increase the sensitivity of detection, over-expression of ZAP-70 was identified in only a minority of B-LL.
流式细胞术免疫表型分析在 B 淋巴细胞白血病（B-LL）的诊断和监测中具有重要作用。然而，人们仍在寻找最佳的试剂组合，以在疾病过程中的任何时间点和每种标本类型中，具有特异性、可重复性和敏感性来识别白血病blasts。
本研究评估了检测细胞质抗原 ZAP-70 和 Bcl-2 在区分 B-LL 的白血病blasts 和造血细胞中的诊断效用。
与参考标本中的造血细胞相比，在 23 例 B-LL 中有 21 例（91%）中鉴定出 Bcl-2 水平明显升高。特别是，与等效的最不成熟（CD10 强阳性）造血细胞相比，Bcl-2 在表达明亮强度 CD10 的白血病blasts 中表达更高。如前所述，Bcl-2 在 BCR-ABL1 基因重排的 B-LL 中表达较低，但该组标本的荧光强度仍明显高于造血细胞。相比之下，仅在 23 例中的 7 例（30%）B-LL 中 ZAP-70 表达水平明显升高，并且具有可能限制临床应用的其他发现，包括治疗过程中 ZAP-70 表达水平的差异以及外周血和骨髓中blasts 之间的差异。
Bcl-2 的过度表达为区分 B-LL 和造血细胞提供了有用的工具。相比之下，尽管进一步优化 ZAP-70 检测可能会提高检测的敏感性，但仅在少数 B-LL 中发现 ZAP-70 的过度表达。
