Isolation and Characterization of Human CD34^+ Hematopoietic Progenitor Cells by High-gradient Magnetic Cell Sorting

Using a high-gradient magnetic cell sorting (MACS) system, CD34^+ cells were isolated from human bone marrow, cord blood, peripheral blood, and cultured in CFU system. The results showed that the excellent recovery (75%) and highest purity (95-99%) were acquired by using the MACS separation system, and the most CFCs were present in CD34^+ population, but not in CD34 fraction by clonogenic assays. The isolation of pure hematopoietic stem cells and progenitor cells is of experimental and clinical importance.

The Cross-talk between ROS and p38MAPKα in the Ex Vivo Expanded Human Umbilical Cord Blood CD133^+ Cells

This study investigated the correlation between and compared the effects of reactive oxygen species（ROS） and p38 mitogen-activated protein kinase α（p38MAPKα） in the ex vivo expanded umbilical cord blood（hUCB） CD133＋ cells.hUCB CD133＋ cells were cultured in the hematopoietic stem cells（HSCs） culture medium with N-acetylcysteine（NAC,an anti-oxidant）,p38MAPKα-specific inhibitor（SB203580） or their combination.The levels of ROS and expression of phosphorylated p38MAPKα（p-p38） in CD133＋ cells were flow cytometrically detected.The efficacy of ex vivo expansion was evaluated by the density of CD133＋ cell sub-group colony-forming cells（CFC） and cobblestone area-forming cells（CAFC） assay.Our results showed decreased ROS levels in NAC,SB203580,and their combination treatment groups were almost 37%,48%,and 85%,respectively.Furthermore,SB203580 abrogated the activation of p38MAPKα more obviously than NAC.Moreover,the CD133＋ cells in SB203580 treatment group had a 21.93±1.36-fold increase,and 14.50±1.19-fold increase in NAC treatment group,but only 10.13±0.57-fold increase in control group.In addition,SB203580 treatment led a higher level increase in the number of CFU and CAFC than NAC did.These findings suggested that,in expanded CD133＋ cells,ROS activates p38MAPKα,which,in turn,induces ROS production,and p38MAPKα might be the most suitable regulator in ROS-p38MAPKα pathway for the promotion of HSCs ex vivo expansion.

HUMAN PRIMITIVE HEMATOPOIETIC PROGENITOR CELLS ARE MORE ENRICHED IN CD34^+CD38^- POPULATION THAN IN CD34^+CD38^+ POPULATION

To clarify the hematopoietic potential of various sub-classes of human hematopoietic progenitor cells, we used a multicolor staining protocol in conjunction with anti-CD34 and -CD38 McAb. We characterized two cell fractions in CD34+cells with or without CD38 expression. A clonogenic assay showed that most CFC were present in CD34+CD38+ population. Morphologic analysis showed that blast-like cells were more enriched in the CD34+CD38 fraction. To clarify the biologic differences between both fractions, we examined the more primitive progenitor cell function by assessing long-term culture-initiating cells (LTC-IC) on the stromal cells. At the first two weeks, more CF.C harvested from the culture in the fractions initiated with both populations. However, more LTC-IC were present during weeks 4 to 12 in the CD34+CD38- population. These results indicate the primitive progenitors are more enriched in CD34+CD38 population than in CD34+CD38+ cells.

High frequency of CD34+CD38-/low immature leukemia cells is correlated with unfavorable prognosis in acute myeloid leukemia

AIM To evaluate the importance of the CD34+CD38-cell population when compared to the CD34+CD38+/low and CD34+CD38+/high leukemic cell sub-populations and to determine its correlations with leukemia characteristics and known prognostic factors, as well as with response to therapy and survival.METHODS Two hundred bone marrow samples were obtained at diagnosis from 200 consecutive patients with newly diagnosed acute myeloid leukemia(AML) were studied between September 2008 and December 2010 at our Institution(Hematology Department, Lyon, France). The CD34/CD38 cell profile was analyzed by multiparameter flowcytometry approach using 8 C panels and FACS CANTO and Diva software(BD Bioscience).RESULTS We analyzed CD34 and CD38 expression in bone marrow samples of 200 AML patients at diagnosis, and investigated the prognostic value of the most immature CD34+CD38-population. Using a cut-off value of 1% of CD34+CD38-from total "bulk leukemic cells" we found that a high(> 1%) level of CD34+CD38-blasts at diagnosis was correlated with advanced age, adverse cytogenetics as well as with a lower rate of complete response after induction and shorter disease-free survival. In a multivariate analysis considering age, leukocytosis, the % of CD34+ blasts cells and the standardized cytogenetic and molecular risk subgroups, a percentage of CD34+CD38-leukemic cells > 1% was an independent predictor of DFS [HR = 2.8(1.02-7.73), P = 0.04] and OS [HR = 2.65(1.09-6.43), P = 0.03].CONCLUSION Taken together, these results show that a CD34/CD38 "backbone" for leukemic cell analysis by multicolour flowcytometry at diagnosis provides useful prognostic information.

人造血干/祖细胞多态性的研究:Ⅷ.人正常骨髓 CD34^+造血细胞体视学的特征

人CD34^+造血细胞是具有高度自我更新、多向分化及重建长期造血与免疫学功能的独特体细胞。为系统探索CD34^+造血细胞的形态、细胞化学及超微结构特征,新近我们设计组合并建立了CIMS-100-FACS 440无菌二次分选术,可使所获CD34^+造血细胞的纯度达100%。在此基础上,本研究采用Cambri-dge Quantimet 970全自动图像分析仪对光学显微镜、扫描电镜及透射电镜下的CD34^+造血细胞进行了体视学方面的某些探讨,进一步从三维结构信息中深刻揭示CD34^+造血细胞的形态计量学特征。经扫描→模数转换←阴影校正→图像暂存←统计分析等检测,结果表明:CD34^+造血细胞的直径3.490—6.741μm,周长11.776—26.240μm,面积9.565—35.686μm^2,形状因子1.048—1.840,核浆比0.58—0.72,平均光密度0.17675—0.65100,积分光密度2717.217—9870.643。由此可见CD34^+造血细胞的确为非均一细胞群,这可能与CD34^+造血细胞的功能亚群与分化阶段密切相关。据我们所知,这是国际上首次有关人CD34^+造血细胞体视学特征的报道。