Freedman M H, Hitzler J K, Bunin N, Grunberger T, Squire J
Department of Pediatrics, Hospital for Sick Children, University of Toronto, Ontario, Canada.
Stem Cells. 1996 Nov;14(6):690-701. doi: 10.1002/stem.140690.
Juvenile chronic myelogenous leukemia (JCML) is a hematologic malignancy of monocyte-macrophage lineage in which leukemic progression is mediated in an autocrine manner by tumor necrosis factor (TNF-alpha), GM-CSF and possibly other growth factors. Cytogenetic data showing involvement of both erythroid and monocyte-macrophage lineages in the JCML leukemic clone, as well as an observed episode of B-lineage lymphoid blast crisis in JCML, has strengthened the thesis for a lympho-hematopoietic pluripotent stem cell origin for the disorder. To study this further, JCML CD34+ cells from bone marrow (BM) or spleen from six newly diagnosed patients were isolated and cultured in clonogenic assays with combinations of recombinant cytokines. Compared to control CD34+ cells, JCML cells from all patients showed an aberrant growth pattern restricted almost exclusively to the monocyte-macrophage lineage. Most of the clonogenic activity was seen in a subsorted population of CD34+, HLA-Dr- cells. Additionally, an exaggerated growth response to minute doses of GM-CSF that had no effect on control cells was observed with JCML CD34+ cells. Recloning ("self-renewal") of JCML CD34+ cells was also strongly promoted by GM-CSF. JCML colonies also formed spontaneously in the absence of exogenous cytokines but were augmented by GM-CSF, interleukin 1 and TNF-alpha, the latter feature not seen with control CD34+ cells from normal BM. The abnormal spontaneous growth pattern of CD34+ JCML cells could be suppressed directly in vitro by anti-TNF-alpha antibodies and anti-GM-CSF antibodies alone or in combination, and by soluble TNF-alpha receptors (sTNF-R:Fc), consistent with the notion that JCML CD34+ cells are stimulated by both cytokines in an autocrine manner. In malignant CD34+ cells from one patient, the cytogenetic marker monosomy 7 proved leukemic involvement of monocyte-macrophage, erythroid and B-lymphoid lineages. We conclude that CD34+ JCML cells of multilineage potential exhibit excessive and aberrant monocyte-macrophage colony formation, a property that was previously observed in JCML progenitors found in light density cell fractions. Thus, within the CD34+ cellular compartment is a subpopulation of JCML "stem" cells that accounts for the abnormal leukemic proliferative activity in this disease.
青少年慢性粒细胞白血病（JCML）是一种单核细胞 - 巨噬细胞系的血液系统恶性肿瘤，其中白血病的进展由肿瘤坏死因子（TNF-α）、粒细胞 - 巨噬细胞集落刺激因子（GM-CSF）以及可能的其他生长因子以自分泌方式介导。细胞遗传学数据显示红系和单核细胞 - 巨噬细胞系均参与了JCML白血病克隆，并且在JCML中观察到了B系淋巴母细胞危象，这强化了该疾病起源于淋巴 - 造血多能干细胞的论点。为了进一步研究这一点，从6例新诊断患者的骨髓（BM）或脾脏中分离出JCML CD34+细胞，并在克隆形成试验中与重组细胞因子组合进行培养。与对照CD34+细胞相比，所有患者的JCML细胞均表现出异常的生长模式，几乎完全局限于单核细胞 - 巨噬细胞系。大多数克隆形成活性见于CD34+、HLA-Dr-细胞的一个亚分选群体中。此外，观察到JCML CD34+细胞对微量GM-CSF有过度的生长反应，而这对对照细胞无影响。GM-CSF也强烈促进JCML CD34+细胞的再克隆（“自我更新”）。JCML集落也可在无外源性细胞因子的情况下自发形成，但GM-CSF、白细胞介素1和TNF-α可增强其形成，而正常BM的对照CD34+细胞未见此特征。单独或联合使用抗TNF-α抗体、抗GM-CSF抗体以及可溶性TNF-α受体（sTNF-R:Fc）可在体外直接抑制CD34+ JCML细胞异常的自发生长模式，这与JCML CD34+细胞受这两种细胞因子自分泌刺激的观点一致。在一名患者的恶性CD34+细胞中，细胞遗传学标记7号染色体单体证明单核细胞 - 巨噬细胞、红系和B淋巴细胞系均有白血病累及。我们得出结论，具有多系潜能的CD34+ JCML细胞表现出过度且异常的单核细胞 - 巨噬细胞集落形成，这一特性先前在低密度细胞组分中发现的JCML祖细胞中也有观察到。因此，在CD34+细胞区室中存在一个JCML“干细胞”亚群，它导致了该疾病中异常的白血病增殖活性。
