Miyachi H, Tanaka Y, Gondo K, Kawada T, Kato S, Sasao T, Hotta T, Oshima S, Ando Y
Department of Clinical Pathology, Tokai University School of Medicine, Isehara, Japan.
Am J Hematol. 1999 Nov;62(3):159-64. doi: 10.1002/(sici)1096-8652(199911)62:3<159::aid-ajh5>3.0.co;2-4.
Specific expression of different CD45 isoforms can be seen in various stages of differentiation of normal nucleated hematopoietic cells. Association of membrane expression of CD45 isoforms and differential levels of leukemia cells was studied in 91 cases with de novo acute myeloid leukemia (AML). Membrane expression of CD45RA and CD45RO was analyzed by flow cytometry and their expression patterns were compared with AML subtypes classified according to the French-American-British (FAB) classification. CD45RA was essentially expressed in all of the FAB myelocytic subtypes (M0-M3). Its expression in percentage was lower in the most differentiated subtype of AML (M3) when compared with other myelocytic subtypes. CD45RO expression was rarely observed in cases with myelocytic subtypes (1/56 cases of M0, M1, M2, and M3) except for the minimally differentiated myelocytic subtype (M0) or those with potential for differentiation to T-cell lineage where three of 12 cases showed CD45RO expression. When leukemia cells of an M3 case were differentiated to mature granulocytes by treatment of all-trans-retinoic acid, they showed increasing expression of CD45RO. In subtypes with a monocytic component (M4 and M5), both of CD45RA and CD45RO expression were observed and mutually exclusive. When 10 cases of M5 were subdivided by the differential level into undifferentiated (M5a) and differentiated monocytic leukemia (M5b), expression of CD45RA and CD45RO was strictly restricted to cases with M5a and M5b, respectively. These results suggest that CD45 isoform expression in AML characterizes differential levels both in myelocytic and monocytic lineages and specifically disturbed in each subtype. The assessment of CD45 isoform expression appears to provide an insight on biological characteristics and a useful supplementary test for differential diagnosis of AML subtypes.
在正常有核造血细胞的不同分化阶段可观察到不同CD45亚型的特异性表达。对91例初发急性髓系白血病（AML）患者研究了CD45亚型的膜表达与白血病细胞不同水平之间的关联。采用流式细胞术分析CD45RA和CD45RO的膜表达，并将其表达模式与根据法国-美国-英国（FAB）分类法分类的AML亚型进行比较。CD45RA基本表达于所有FAB髓细胞亚型（M0-M3）。与其他髓细胞亚型相比，其在AML最分化亚型（M3）中的表达百分比更低。除了低分化髓细胞亚型（M0）或有向T细胞系分化潜能的病例（12例中有3例显示CD45RO表达）外，在髓细胞亚型病例中很少观察到CD45RO表达（M0、M1、M2和M3病例中56例中有1例）。当M3病例的白血病细胞经全反式维甲酸处理分化为成熟粒细胞时，它们显示出CD45RO表达增加。在有单核细胞成分的亚型（M4和M5）中，观察到CD45RA和CD45RO的表达且二者相互排斥。当将10例M5病例按分化程度细分为未分化（M5a）和分化型单核细胞白血病（M5b）时，CD45RA和CD45RO的表达分别严格局限于M5a和M5b病例。这些结果表明，AML中CD45亚型表达在髓细胞系和单核细胞系中均表征了不同的分化水平，且在各亚型中存在特异性紊乱。CD45亚型表达的评估似乎可为AML亚型的生物学特征提供见解，并为鉴别诊断提供有用的补充检测。
