Migratory behavior of leukemic cells from acute myeloid leukemia patients.

The chemokine stromal cell-derived factor-1 (SDF-1) and its receptor CXCR-4 contribute to stem cell homing and may play a role in the trafficking of leukemic cells. Therefore, we analyzed migration across Transwell filters of cells derived from bone marrow (BM) or peripheral blood (PB) from 26 acute myeloid leukemia (AML) patients. The presence of the extracellular matrix protein fibronectin (FN) strongly enhanced the spontaneous and SDF-1-induced migration of leukemic PB and BM cells. No differences in spontaneous, SDF-1-induced migration or CXCR-4 expression were observed between the different AML subtypes. Subsequently, it was determined whether SDF-1 preferentially promoted migration of subsets of leukemic cells. Leukemic cells expressing CD34, CD38 and HLA-DR were preferentially migrating, whereas cells expressing CD14 and CD36 showed diminished migration. Analysis of paired PB and BM samples indicated that significantly higher SDF-1-induced migration was observed in AML for CD34(+) BM-derived cells compared to CD34(+) PB-derived cells, suggesting a role for SDF-1 in the anchoring of leukemic cells in the BM or other organs. The lower percentage of circulating leukemic blasts in patients with a relatively high level of SDF-1-induced migration also supports this hypothesis. In conclusion, we have shown that primary AML cells are migrating towards SDF-1 independent of the AML subtypes.     

骨髓增生异常综合征中CD34+细胞CXCR4的表达及其与细胞迁移的相关性

  目的  探讨不同危险度骨髓增生异常综合征（myelodysplasticsymdromes,MDS）中骨髓CD34+细胞CXCR4的表达情况及其与细胞迁移率的相关性。   方法  收集40例骨髓增生异常综合征患者的骨髓标本,根据IPSS积分系统进行危险度分组。低危组20例:IPSS积分0~1.5分;高危组20例:IPSS积分≥1.5分;同时采集10例健康者的骨髓标本作为对照。分离纯化骨髓CD34+细胞,通过流式细胞术检测CXCR4膜蛋白的表达;研究SDF-1α趋化作用下CD34+细胞的迁移率及CD34+细胞对骨髓基质细胞的迁移率。   结果  高危组MDS患者CD34+细胞CXCR4的表达率明显高于低危组和正常对照组（P < 0.000 1）;低危组和正常对照组之间CXCR4的表达率无显著性差异（P>0.05）。高危组CD34+细胞对SDF-1α及骨髓基质细胞的迁移率显著高于低危组及正常组（均P < 0.000 1）,且其对骨髓基质细胞的迁移率与CXCR4的表达呈正相关（P=0.000 1）。   结论  高危组MDS患者CD34+细胞CXCR4的表达量及其对骨髓基质细胞的迁移率均明显高于低危组患者,且其迁移率随CXCR4表达量的增加而升高,不同风险组的MDS患者存在SDF-1及其受体CXCR4表达和功能上的差异,SDF-1及其受体CXCR4在MDS发病中具有重要作用。      

Proliferating status of peripheral blood progenitor cells from patients with BCR/ABL-positive chronic myelogenous leukemia.

To investigate the mechanisms behind the leukemic expansion of BCR/ABL-positive chronic myelogenous leukemia (CML), we examined the cell cycle status of hematopoietic progenitor cells from peripheral blood (PB) and bone marrow (BM) of 37 patients with newly diagnosed BCR/ABL-positive CML. We found a high proportion of 12.51 +/- 1.19% of CD34+ peripheral blood progenitor cells (PBPC) in S/G2M phase. Comparison of PB and BM from 19 cases revealed similar proliferation rates (10.74 +/- 1.41% vs 15.97 +/- 1.95%). Furthermore, even primitive CD34+/CD38- PBPC displayed high proliferation rates (17.45 +/- 2.98%) in 10 cases examined. In contrast, PBPC from 11 patients with BCR/ABL-negative myeloproliferative disorders were almost noncycling (S/G2M 1.46 +/- 0.47%). When matched pairs of PB and BM from six patients with BCR/ABL-negative myeloproliferative disorders were examined, only 0.89 +/- 0.41% of the CD34+ PBPC, but 8.29 +/- 3.13% CD34+ cells from BM were in S/G2M phase. Consistently, as compared to 19 patients with newly diagnosed BCR/ABL-positive CML, a significantly lower PB/BM ratio of CD34+ cells in S/G2M phase was found in these six patients with BCR/ABL-negative myeloprolifrative disorders. Administration of the tyrosine kinase inhibitor STI571 to 13 patients with CML in chronic phase, accelerated phase, or blast crisis lead to an inhibition of PBPC proliferation within a few days. Interestingly, CD34+ hematopoietic progenitor cells from BM remained proliferating in five cases examined, indicating that CML PBPC are more easily inhibited by STI571 as compared to CD34+ CML hematopoietic progenitor cells from BM. These data suggest that BCR/ABL leads to an enhanced cell cycle activation of CD34+ cells, which seems to be, at least in part, independent of additional factors provided by the bone marrow microenvironment.     

CD14+ peripheral blood mononuclear cells from chronic myeloid leukemia and normal donors are inhibitory to short- and long-term cultured colony-forming cells

Monocyte-induced cell-cytotoxicity has been implicated in the mechanism of suppression of normal haematopoietic progenitors in chronic myeloid leukemia (CML). We examined here the in vitro effect of CML-derived and normal peripheral blood (PB) monocytes on short- and long-term cultured haematopoietic progenitor cells. Short-term coculture (5 days) of CML or normal monocytes with CML or normal peripheral blood mononuclear cells (PBMNC)/CD34+ cells as targets resulted in a significant inhibition of colony-forming cell (CFC) growth. Coculture conditioned medium (CCM) from 5-days cocultures of normal or CML CD14+ monocytes with CD34+ cells were likewise inhibitory to CFC. In 5-week long-term cocultures of monocytes in direct contact with normal bone marrow (BM) progenitors, CML monocytes reduced the proportion of long-term cultured CFC (LTC-CFC) significantly to 52% of the controls, while normal monocytes had a less pronounced inhibitory effect (89% of the controls) on LTC-CFC. Reduction of LTC-CFC was great when CML monocytes and target cells were separated by a transwell membrane as compared to control cultures in the absence of CD14+ cells (53.5 vs. 9%). CCM from 5-week cocultures of normal or CML CD14+ monocytes with CD34+ progenitors from bone marrow (BM) cells were also inhibitory to CFC. No difference in cytokine levels for TNF-alpha, IFN-gamma, G-CSF, IL-10, IL-6 was detectable between CML CD14+ CCM and control CCM derived from short- and long-term cocultures. Our results suggest that CML monocytes may play a role in the inhibition of normal haematopoiesis through a yet not defined soluble factor supporting the expansion of the malignant clone in CML.     

Stem cell plasticity revisited: CXCR4-positive cells expressing mRNA for early muscle, liver and neural cells 'hide out' in the bone marrow.

It has been suggested that bone marrow (BM)-derived hematopoietic stem cells transdifferentiate into tissue-specific stem cells (the so-called phenomenon of stem cell plasticity), but the possibility of committed tissue-specific stem cells pre-existing in BM has not been given sufficient consideration. We hypothesized that (i) tissue-committed stem cells circulate at a low level in the peripheral blood (PB) under normal steady-state conditions, maintaining a pool of stem cells in peripheral tissues, and their levels increase in PB during stress/tissue injury, and (ii) they could be chemoattracted to the BM where they find a supportive environment and that the SDF-1-CXCR4 axis plays a prominent role in the homing/retention of these cells to BM niches. We performed all experiments using freshly isolated cells to exclude the potential for 'transdifferentiation' of hematopoietic stem or mesenchymal cells associated with in vitro culture systems. We detected mRNA for various early markers for muscle (Myf-5, Myo-D), neural (GFAP, nestin) and liver (CK19, fetoprotein) cells in circulating (adherent cell-depleted) PB mononuclear cells (MNC) and increased levels of expression of these markers in PB after mobilization by G-CSF (as measured using real-time RT-PCR). Furthermore, SDF-1 chemotaxis combined with real-time RT-PCR analysis revealed that (i) these early tissue-specific cells reside in normal murine BM, (ii) express CXCR4 on their surface and (iii) can be enriched (up to 60 x) after chemotaxis to an SDF-1 gradient. These cells were also highly enriched within purified populations of murine Sca-1(+) BM MNC as well as of human CD34(+)-, AC133(+)- and CXCR4-positive cells. We also found that the expression of mRNA for SDF-1 is upregulated in damaged heart, kidney and liver. Hence our data provide a new perspective on BM not only as a home for hematopoietic stem cells but also a 'hideout' for already differentiated CXCR4-positive tissue-committed stem/progenitor cells that follow an SDF-1 gradient, could be mobilized into PB, and subsequently take part in organ/tissue regeneration.     

Characterisation of the differential response of normal and CML haemopoietic progenitor cells to macrophage inflammatory protein-1alpha.

The clonogenic cells of chronic myeloid leukaemia (CML), unlike normal haemopoietic colony forming cells (CFC), are resistant to the growth inhibitory effects of the chemokine, macrophage inflammatory protein-1alpha (MIP-1alpha). Here, we tested the hypothesis that MIP-1alpha protects normal, but not CML, CFC from the cytotoxic effects of the cell-cycle active drug cytosine arabinoside (Ara-C). Using a 24-h Ara-C protection assay we showed that MIP-1alpha confers protection to normal CFC but also sensitizes CML CFC to Ara-C. The differential MIP-1alpha responsiveness was not due to a down-regulation of MIP-1alpha receptors on CML CD34+ cells as flow cytometric analysis showed similar binding of a biotinylated MIP-1alpha molecule to normal and CML CD34+ cells. Flow cytometric analysis of the MIP-1alpha receptor subtype CCR-5 revealed comparable CCR-5 expression levels on normal and CML CD34+ cells. Furthermore, culture of CD34+ cells for 10 h in the presence of TNF-alpha resulted in an increased MIP-1alpha receptor expression on both normal and CML CD34+ cells. Our data suggest that the unresponsiveness of CML CFC to the growth inhibitory effect of MIP-1alpha is not caused by a lack of MIP-1alpha receptor or total uncoupling of the MIP-1alpha responsiveness but may be due to an intracellular signalling defect downstream of the receptors.     

Distinct molecular phenotype of malignant CD34(+) hematopoietic stem and progenitor cells in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is a malignant disorder of the hematopoietic stem cell characterized by the BCR-ABL oncogene. We examined gene expression profiles of highly enriched CD34(+) hematopoietic stem and progenitor cells from patients with CML in chronic phase using cDNA arrays covering 1.185 genes. Comparing CML CD34(+) cells with normal CD34(+) cells, we found 158 genes which were significantly differentially expressed. Gene expression patterns reflected BCR-ABL-induced functional alterations such as increased cell-cycle and proteasome activity. Detoxification enzymes and DNA repair proteins were downregulated in CML CD34(+) cells, which might contribute to genetic instability. Decreased expression of junction plakoglobulin and CXC chemokine receptor 4 (CXCR-4) might facilitate the release of immature precursors from bone marrow in CML. GATA-2 was upregulated in CML CD34(+) cells, suggesting an increased self-renewal in comparison with normal CD34(+) cells. Moreover, we found upregulation of the proto-oncogene SKI and of receptors for neuromediators such as opioid mu1 receptor, GABA B receptor, adenosine A1 receptor, orexin 1 and 2 receptors and corticotropine-releasing hormone receptor. Treatment of CML progenitor cells with the selective adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) resulted in a dose-dependent significant inhibition of clonogenic growth by 40% at a concentration of 10(-5) M, which could be reversed by the equimolar addition of the receptor agonist 2-chloro-N6-cyclopentyladenosine (P<0.05). The incubation of normal progenitor cells with DPCPX resulted in an inhibition of clonogenic growth to a significantly lesser extent in comparison with CML cells (P<0.05), suggesting that the adenosine A1 receptor is of functional relevance in CML hematopoietic progenitor cells.     

Stromal cell-derived factor-1 stimulates vasculogenesis and enhances Ewing's sarcoma tumor growth in the absence of vascular endothelial growth factor

Stromal cell-derived Factor-1alpha (SDF-1alpha) stimulates the migration of bone marrow (BM) cells, similar to vascular endothelial growth factor (VEGF). We previously demonstrated that inhibition of VEGF(165) by small interfering RNA inhibited Ewing's sarcoma tumor growth, tumor vessel formation and recruitment of BM cells to the tumor. To determine the importance of BM cells in tumor vessel development, we investigated the effects of SDF-1alpha on VEGF-inhibited TC/siVEGF(7-1) Ewing's tumor neovasculature formation and growth. The effect of SDF-1alpha on CD34(+) progenitor cell chemotaxis was determined in vivo. Using a BM transplantation model with GFP(+) transgenic mice as BM donors and nude mice as recipients, we evaluated the effect of SDF-1alpha on the recruitment of BM-derived cells to VEGF(165)-inhibited TC/siVEGF(7-1) tumors, as well as its effect on neovasculature development, vessel morphology and tumor growth. SDF-1alpha stimulated the migration of CD34(+) progenitor cells to Matrigel plugs in vivo and promoted the retainment of BM-derived pericytes in close association with perfused, functional tumor vessels. Intratumor inoculation of Ad-SDF-1alpha into TC/siVEGF(7-1) tumors resulted in increased SDF-1 and PDGF-BB expression, augmented tumor growth, an increase in the number of large, lumen-bearing vascular structures, and enhanced vessel pericyte coverage, with no change in VEGF(165). SDF-1alpha stimulates BM cell chemotaxis and the association of these cells with functional tumor vessels. Furthermore, SDF-1alpha enhances tumor neovascularization and growth with no alteration in VEGF(165). Our work suggests that SDF-1-mediated vasculogenesis may represent an alternate pathway that could potentially be utilized by tumors to sustain growth and neovasculature expansion after anti-VEGF therapy.     

BCR/ABL-mediated downregulation of genes implicated in cell adhesion and motility leads to impaired migration toward CCR7 ligands CCL19 and CCL21 in primary BCR/ABL-positive cells.

The mechanism underlying p210(BCR/ABL) oncoprotein-mediated transformation in chronic myelogenous leukemia (CML) is not fully understood. We hypothesized that p210(BCR/ABL) suppresses expression of genes which may explain at least some of the pathogenetic features of CML. A subtractive cDNA library was created between BCR/ABL-enhanced-green-fluorescent-protein (GFP)-transduced umbilical cord blood (UCB) CD34+ cells and GFP-transduced UCB CD34+ cells to identify genes whose expression is downregulated by p210(BCR/ABL). At least 100 genes were identified. We have confirmed for eight of these genes that expression was suppressed by quantitative real-time-RT-PCR (Q-RT-PCR) of additional p210(BCR/ABL)-transduced CD34+ UCB cells as well as primary early chronic phase (CP) bone marrow (BM) CML CD34+ cells. Imatinib mesylate reversed downregulation of some genes, to approximately normal levels. Several of the genes are implicated in cell adhesion and motility, including L-selectin, intercellular adhesion molecule-1 (ICAM-1), and the chemokine receptor, CCR7, consistent with the known defect in adhesion and migration of CML cells. Compared with GFP UCB or normal (NL) BM CD34+ cells, p210 UCB and CML CD34+ cells migrated poorly towards the CCR7 ligands, CCL19 and CCL21, suggesting a possible role for CCR7 in the abnormal migratory behavior of CML CD34+ cells.     

Morphologic, immunophenotypic and in vitro growth characteristics of blood and bone marrow associated with stem cell mobilisation in patients with lymphoma

The proportion of CD34+ cells in the bone marrow (BM) is predictive of the size of progenitor cell mobilisation into the blood (PB). To investigate which other PB and BM parameters may be related to mobilisation, we analysed at steady state PB and BM of 23 patients with relapsed or resistant lymphoma before administering high-dose cyclophosphamide and G-CSF Cell morphology, number of CD34+ cells, and growth in clonogenic assay and in long-term cultures (LTC) were determined and then correlated with mobilisation extent (CD34+ and GM-CFC) and quality (growth of harvested cells in LTC). We found that the good mobilising patients (CD34 > 50 x 10(3)/ml, n=10) had several baseline BM characteristics (number of CD34+ MNC, GM-CFC, BFU-E, production of CFCs in LTC) similar to a group of 12 healthy controls, while patients with reduced mobilisation (CD34 < 50 x 10(3)/ml, n=13) had clearly reduced BM progenitors and LTC growth (p< 0.05). In a multivariate analysis including baseline clinical, blood and bone marrow characteristics, the most significant PB and BM factors independently associated with a higher number and/or quality of mobilised cells were a higher number of CD34+ and GM-CFC in the BM and a higher baseline haemoglobin, platelet, and CD34+ blood count. The capacity to release progenitor cells into the circulation is therefore not predicted by the distribution of morphologically distinguishable cells, marginally predicted by the BM content of highly undifferentiated cells (growth in long term culture), while it is proportional to the number of BM progenitors (CD34+, GM-CFC and BFU-E).     

自体外周血造血干细胞移植过程中淋巴细胞亚群和CD34+细胞变化的动态研究

目的动态观察动员、采集过程中外周血及造血干细胞中的淋巴细胞亚群和造血干细胞含量变化,及时指导临床选择最佳采集时机。方法 采用流式细胞术(FCM)测定大剂量化疗(HDC)联合重组人粒细胞集落刺激因子(rhG-CSF)对47例恶性实体瘤患者自体外周血造血干细胞移植(APBSCT)过程中,外周血和外周血造血干细胞(PBPC)中的淋巴细胞亚群CD3、CD4、CD8、NK、CD19和造血干细胞CD34+及其亚群CD34+CD38-、CD34+ Thy1+、AC133+细胞含量的变化,同时用体外集落培养的方法评价干细胞克隆形成能力。结果 动员后外周血淋巴细胞亚群CD3、CD4、CD8、NK和CD19细胞含量均低于动员前,其中CD3、CD8含量明显低于基础状态(P=0.007,P=0.016),而动员后外周血中的CD34及其亚群含量均明显高于动员前(P<0.05)。动员后中位时间第16天(15～17 d)外周血中的CD34含量达到最高峰,且第1次采集物中的造血干细胞含量最高。PBPC中除CD4、CD4/CD8明显低于外周血外(P<0.000 5),其他淋巴细胞亚群含量与外周血比较无明显改变。外周血单个核细胞中CD34+细胞含量与PBPC中CD34+细胞、CD34+CD38-及粒/单系集落形成单位(CFU-GM)、红系爆式集落形成单位(BFU—E)均存在显著相关性(P<0.05),而与采集的单个核细胞(MNC)总数、CD34+Thy1+、AC133+细胞含量间无相关关     

调节性T细胞在慢性粒细胞白血病中的表达及临床意义

  目的   分析CD4+CD25+Treg细胞在慢性粒细胞白血病（CML）患者不同病程中的表达,探讨其与该疾病的疗效及预后的关系,从免疫学方面揭示CML发生及转归的可能机制。   方法   收集23例不同病程分期CML患者及10例健康对照的外周血,采用流式细胞仪技术对CD4+CD25+Treg细胞进行检测,比较CML患者与对照之间及不同病程CML患者之间CD4+CD25+Treg细胞表达的差异;比较CD4+CD25+Treg细胞表达水平与对应的临床参数间的关系。   结果   与正常对照比较,CML初治患者、加速急变期患者外周血单个核细胞中CD4+CD25+Treg细胞百分比呈显著性下降（P < 0.05）;而CML慢性治疗期患者外周血单个核细胞中CD4+ CD25+Treg细胞百分比与正常对照比较无显著性差异（P>0.05）;与正常对照比较,CML初治患者、加速急变期患者外周血单个核细胞中CD4+Treg细胞百分比呈显著性下降（P < 0.05）;而CML慢性治疗期患者外周血单个核细胞中CD4+Treg细胞百分比与正常对照比较无显著性差异（P>0.05）;不同病程CML患者外周血单个核细胞中CD4+CD25+Treg细胞百分比相比较,慢性稳定期患者较初治患者有明显上升,差异有统计学意义（P < 0.05）;而其他组之间无显著性差异（P>0.05）;初治CML患者外周血单个核细胞中CD4+ CD25+Treg细胞百分比与外周血血红蛋白量呈正相关（P=0.010）;与骨髓中幼稚细胞（原始粒细胞+早幼粒细胞）百分比呈负相关（P=0.022）。   结论   CML患者外周血单个核细胞中CD4+CD25+Treg细胞占外周血单个核细胞的比例下降,提示患者进入加速急变期CD4+CD25+Treg细胞在CML患者中起到一定的免疫调节作用。      

Multilineage outgrowth of both malignant and normal hemopoietic progenitor cells from individual chronic myeloid leukemia patients in immunodeficient mice.

In this study the ability of malignant and normal progenitors in peripheral blood (PB) and bone marrow (BM) of CML patients in chronic phase to proliferate and produce mature progeny after transplantation into hereditary immunodeficient (SCID and NOD/SCID) mice was examined. Engraftment in NOD/SCID mice preconditioned by total body irradiation (TBI) alone was 10-fold higher than in SCID mice preconditioned by macrophage depletion and TBI, demonstrating that NOD/SCID mice are more suitable for engraftment of chronic phase CML cells. Low-density cells at cell doses of 10-30 x 10(6) and purified CD34+ cells at doses of approximately 0.2 x 10(6) engrafted NOD/SCID mice, with levels of 2 to 20% CD45+ cells with production of monocytes, granulocytes, erythroid cells, B-lymphocytes, CD34+ cells and variable frequencies of erythroid and myeloid colony-forming cells. As demonstrated by fluorescent in situ hybridization (FISH) analysis, purified human myeloid, B-lymphoid, erythroid and CD34+ cells from chimeric mouse BM contained Philadelphia-chromosome (Ph)-positive cells and Ph- cells in similar frequencies as primary cells from the CML patients. These results demonstrate that production of mature normal as well as malignant cells of multiple lineages were supported with similar efficiency. In contrast, all human erythroid and myeloid clonogenic cells detected in the mice were Ph-, which can be attributed to less efficient maintenance or more rapid differentiation of immature Ph+ cells in the mouse microenvironment. CML blast crisis cells also grew well in NOD/SCID mice, with 80-90% of human cells produced containing the Ph- chromosome. The availability of an in vivo assay that supports outgrowth of normal and malignant stem cells from chronic phase and blast crisis CML patients will facilitate examination of differential effects of growth factors, inhibitory cytokines and cytotoxic drugs on survival of normal and malignant stem cells in vivo and on progression of chronic phase CML towards blast crisis.     

Defective p38 mitogen-activated protein kinase signaling impairs chemotaxic but not proliferative responses to stromal-derived factor-1alpha in acute lymphoblastic leukemia

The chemokine stromal-derived factor-1alpha (SDF-1alpha) regulates leukemic cell motility and proliferation; however, the importance of these functions in the growth and dissemination of leukemia is unclear. We examined SDF-1alpha-mediated responses of cells from 27 cases of acute lymphoblastic leukemia (ALL). Although cells from the majority of cases showed chemotactic and proliferative responses to SDF-1alpha, a subset of cases did not undergo chemotaxis in response to SDF-1alpha, while still demonstrating dependence on SDF-1alpha for proliferation in stroma-supported cultures. This chemotactic defect was associated with an absence of phosphorylation of p38 mitogen-activated protein kinase (MAPK) induced by SDF-1alpha, and of SDF-1alpha-induced augmentation of beta(1) integrin-mediated adhesion. Signaling through phosphoinositide 3-kinase and MEK was not affected. No correlation was observed between CXCR4 expression and chemotactic function, in vitro migration into bone marrow stromal layers, and engraftment of leukemic cells in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. This study suggests that signaling through p38 MAPK is required for ALL cell chemotaxis but not for proliferation, and that the loss of a chemotactic response to SDF-1alpha does not impede engraftment in NOD/SCID mice.     

Tumour kinetics in multiple myeloma before, during, and after treatment.

Tumour progression was monitored in seven multiple myeloma (MM) patients undergoing a novel oral chemotherapy regimen (cyclophosphamide, idarubicin and dexamethasone; CID) followed by early autologous stem cell transplantation (ASCT). Allele-specific oligonucleotide PCR (ASO-PCR) was used to semi-quantitate the number of tumour cells within the peripheral blood (PB) and PB progenitor cell (PBPC) harvests and compared with paraprotein levels and morphological bone marrow (BM) assessments. Tumour cells were detected in the PB of all patients at diagnosis, but decreased in response to CID therapy. All but two of the 22 PBPC collections contained MM cells, the levels of which were statistically correlated with overall clinical response to therapy, but not with individual BM or PB tumour loads prior to mobilisation. We also found no correlation between the day of leucapheresis collection and the number of contaminating MM cells, CD34+ cells or MM cells per CD34+ cell. Regardless of tumour contamination levels in the PBPC collections, the majority of patients demonstrated post-ASCT clearing of circulating MM cells. This study suggests that levels of circulating MM cells may be the best indication of patient response to treatment and argues against the theory of differential mobilisation of tumour cells and CD34+ cells in response to cytokine treatment.     

No expansion of the pre-B and B-cell compartments in the bone marrow of patients with multiple myeloma

We have recently demonstrated that the CD24 antigen density of bone marrow (BM) lymphoid cells discriminates between pre-B cells and mature B-cells. Using this new method, we evaluated the B-cell lineage in the BM and peripheral blood (PB) of 18 patients with multiple myeloma (MM). First, the percentage of pre-B cells was significantly reduced by 40% in the BM of patients with MM: 2.3% +/- 2.2% versus 5.7% +/- 2.8% of normal BM lymphoid cells (P less than 0.01). This finding was associated with a significant reduction (50%) of the percentage of mature B-cells in both BM and PB, especially in patients with progressive disease (P less than 0.05). In contrast to what has been reported previously, we have not found any pre-B cells in the PB of these patients with MM. Secondly, BM pre-B and B-cell patients with MM did not express any activation markers (CD23, CD25, or CD71 antigens) and no CD5+ B-cells were found in the BM unlike in PB (8% CD5+ B-cells). Taken together, these data do not support the concept of a direct involvement (i.e, expansion or activation) of pre-B cells in MM without excluding the possibility of an early oncogenic event at the pre-B cell stage. Furthermore, our data emphasize this important reduction of the B-cell compartment (including that of pre-B cell) as a major cause of the humoral immunodeficiency in MM.     

干扰素及异体骨髓移植对慢性粒细胞白血病细胞β2整合素及L—选择素表达的

目的 探讨慢性粒细胞白血病（ｃｈｒｏｎｉｃ ｍｙｅｌｏｃｙｔｉｃ ｌｅｕｋｅｍｉａ,ＣＭＬ）细胞黏附分子Ｌ－ｓｅｌｅｃｔｉｎ（ＣＤ６２Ｌ）、Ｍａｃ－１（ＣＤ１１ｂ）、ＬＦＡ－１（ＣＤ１１ａ）的表达与ＣＭＬ的发生、疗效的关系。方法 采用三色流式细胞仪检测３４例ＣＭＬ骨髓ＣＤ３４＾＋ＣＤ３８＾－－＋细胞表达ＬＦＡ－１、Ｍａｃ－１、Ｌ－ｓｅｌｅｃｔｉｎ的表达。结果 初治的ＣＭＬ３４＾＋ＣＤ３８＾－－＋细胞黏附分子Ｌ－ｓｅｌｅｃｔｉｎ、ＬＦＡ－１明显低于正常造血细胞的表达。Ｌ－ｓｅｌｅｃｔｉｎ的表达与Ｐｈ’阳性细胞数呈负相关（ｒ＝－０．６８）。８例ＣＭＬ经干扰素治疗后,其Ｌ－ｓｅｌｅｃｔｉｎ、Ｍａｃ－１、ＬＦＡ－１的表达均正常。结论 ＣＭＬＣＤ３４阳性细胞黏附分子Ｌ－ｓｅｌｅｃｔｉｎ、ＬＦＡ－１的低表达反映了ＣＭＬ细胞     

Phenotypic Characterization of Normal and CML CD34-Positive Cells: Only the Most Primitive CML Progenitors Include Ph-neg Cells

We studied the sequence of acquisition of CD33, CD38 and HLA-DR antigens on CD34+ cells from marrow and blood of Ph-chromosome positive CML patients and normal marrow. We examined the Ph status of the various CML cell populations. The mean proportions of normal and CML CD34+ cells expressing CD33 and CD38 were not significantly different. However, a significantly greater proportion of CML CD34+ cells expressed HLA-DR antigens compared with normal CD34+ cells and the level of HLA-DR expression per CML cell was abnormally high. When the sequence of acquisition of these antigens on normal and CML CD34+ cells was evaluated using 3-colour fluorescence analysis, the results suggested that HLA-DR was expressed earlier than CD38 or CD33 and these findings were confirmed by following the acquisition of CD38 and CD34t/DR + /CD38-subpopulation during liquid culture. We performed cytogenetic studies on CD34+ subpopulations in 6 cases. In 4 cases there were some Ph-negative metaphases detectable in the CD34+/DR-subpopulation (range 12.5 to 60%). In the CD34+/DR+ fractions, however, all 6 patients had only Ph-positive metaphases and only 1/5 patients had detectable Ph-negative metaphases in the CD34+/CD38-subpopulation. We conclude that expression of HLA-DR antigens may precede the expression of CD38 on CD34+ cells during normal stem cell differentiation. In CML DR may be expressed aberrantly and Ph-negative cells are found predominantly in the DR negative sub-population.     

Tumour Kinetics in Multiple Myeloma Before, During, and After Treatment

Tumour progression was monitored in seven multiple myeloma (MM) patients undergoing a novel oral chemotherapy regimen (cyclophosphamide, idarubicin and dexamethasone; CID) followed by early autologous stem cell transplantation (ASCT). Allele-specific oligonucleotide PCR (ASO-PCR) was used to semi-quantitate the number of tumour cells within the peripheral blood (PB) and PB progenitor cell (PBPC) harvests and compared with paraprotein levels and morphological bone marrow (BM) assessments. Tumour cells were detected in the PB of all patients at diagnosis, but decreased in response to CID therapy. All but two of the 22 PBPC collections contained MM cells, the levels of which were statistically correlated with overall clinical response to therapy, but not with individual BM or PB tumour loads prior to mobilisation. We also found no correlation between the day of leucapheresis collection and the number of contaminating MM cells, CD34⁺ cells or MM cells per CD34⁺ cell. Regardless of tumour contamination levels in the PBPC collections, the majority of patients demonstrated post-ASCT clearing of circulating MM cells. This study suggests that levels of circulating MM cells may be the best indication of patient response to treatment and argues against the theory of differential mobilisation of tumour cells and CD34⁺cells in response to cytokine treatment.     

Immunophenotypic profile of AC133-positive cells in bone marrow,mobilized peripheral blood and umbilical cord blood

AC133 is a molecule whose expression in the human hematopoietic system is restricted to a subset of CD34+ progenitor/stem cells with long-term repopulating ability. The antigenic features of these cells, like CD34+ cells, are described heterogeneous. The immunophenotypic profile of AC133+ cells, detected by means of dual-color flow cytometry, in bone marrow (BM), cytokine-mobilized peripheral blood (PB) and umbilical cord blood (UCB) was evaluated. The highest percentage of AC133+ cells was detected in mobilized PB despite not significantly different from that found in BM, but both are higher than that found in UCB. In addition, the highest percentage of CD34, HLA-DR and CD33 co-expressing AC133+ cells was observed in mobilized PB. Furthermore, UCB was found to be enriched in CD7+ and CD19+ cells and BM was found to be enriched in AC133+ cells co-expressing CDw90 and CD71. Our data confirm the immunophenotypic heterogeneity of cells expressing AC133 antigen, a promising new stem cell marker to be increasingly used as additional target for alternative identification and separation of early hematopoietic cells.