骨髓增生异常综合征患者骨髓单个核细胞CD34、CD117的表达及其临床意义

 目的　探讨骨髓增生异常综合征（MDS）患者骨髓单个核细胞CD34、CD117的表达及临床意义。方法　采用直接免疫荧光标记法标记细胞表面分化抗原,流式细胞术测定,对37例MDS患者的骨髓单个核细胞CD34、CD117表达及临床意义进行分析。依据MDS的WHO分型方案、染色体核型以及国际预后积分系统（IPSS）将MDS患者划分为RA-RARS-RCMD 组、RAEBⅠ-RAEBⅡ组;染色体良好组、染色体不良组;中危Ⅰ组、中危Ⅱ组、高危组。结果　RA-RARS-RCMD组19例中11例CD34、CD117表达阳性,RAEBⅠ-RAEBⅡ组18例患者CD34、CD117表达均阳性;随着疾病恶性程度的增高,CD34、CD117表达明显升高;染色体良好组22例中14例患者CD34、CD117表达阳性,染色体不良组15例患者均表达CD34、CD117;随着异常克隆的出现,CD34、CD117表达升高;中危Ⅰ组17例中9例CD34、CD117表达阳性;中危Ⅱ组11例、高危组9例,所有患者CD34、CD117表达均阳性;随着预后积分的递增,CD34、CD117表达随之升高。结论　CD34、CD117检测有助于MDS 的分型、预后判断。     

骨髓增生异常综合征患者骨髓单个核细胞CD34、CD117的表达及其临床意义

Objective To explore the expression and significance of CD34, CD117 on bone marrow mononuclear cells of myelodysplastic syndromes (MDS). Methods Direct immunofluorescence staining was used by means of flow cytometry. 37 patients with MDS were divided into RA/RARS/RCMD subgroup, RAEB Ⅰ/RAEB Ⅱ subgroup; favorable chromosomal subgroup, poor chromosomal subgroup; intermediate-risk Ⅰ subgroup, intermediate-risk Ⅱ subgroup, high-risk subgroup respectively according to WHO classification,cytogenetic abnormalities and international prognostic scoring system (IPSS). Results CD34 and CD117 were positive respectively in 11 of 19 patients with RMRARS/RCMD, all cases in RAEB Ⅰ/RAEB Ⅱ expressed CD34 and CD117; increased expression of CD34 and CD117 was MDS grade-related. Favorable chromosomal subgroup, 14 of 22 patients were positive for CD34, CD117, all cases in poor chromosomes expressed CD34 and CD117; there was a direct relationship between phenotytic density and poor cytogenetic risk factor. CD34 and CD117 expression was present respectively in intermediate-risk Ⅰ (9/17), intermediate-risk Ⅱ (11/11) and highrisk subgroup (9/9); the phenotypic intensity also was correlated with IPSS scores. Conclusion Detection of CD34, CD117 may be a useful tool for subtyping and predicting the prognosis of MDS.     

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。      

骨髓增生异常综合征和再生障碍性贫血患者骨髓CD34+细胞测定

 目的 检测骨髓增生异常综合征（MDS）和再生障碍性贫血（AA）患者骨髓CD+34细胞占单个核细胞（MNC）的比率,以探讨二者可能的发病机制。方法 用流式细胞术（FCM）检测22例MDS患者、13例AA患者及12例非血液病患者骨髓CD+34细胞占MNC的比率。结果 AA组与对照组、AA组与MDS-RA组、AA组与MDS-RAEB组、MDS-RA组与MDS-RAEB组的骨髓MNC中CD+34细胞的比率的比较差异有统计学意义（P＜0.05）。大多数重型AA（SAA）患者（3／4）及很少慢性AA（CAA）患者（1／9）的骨髓MNC中的CD+34细胞的比率＜0.1 %。结论 骨髓CD+34细胞的检测有助于判断AA患者病情及MDS患者的预后,亦可用于鉴别AA和MDS。     

Quantitative analysis of bone marrow CD34 cells in aplastic anemia and hypoplastic myelodysplastic syndromes.

Aplastic anemia (AA) and hypoplastic myelodysplastic syndromes (hMDS) are often difficult to distinguish. However, an accurate diagnosis is important because the prognosis and treatment of these diseases may differ. CD34+ hematopoietic progenitors are central to the pathogenesis of both disorders; they are the targets of the autoimmune attack in AA and neoplastic transformation in MDS. The aim of this study was to assess whether bone marrow CD34+ cell numbers could be used in differentiating between AA and hMDS. The percentage of bone marrow CD34+ cells was normal or increased (mean -3.5+0.5%, range 1-7%) in 15 of 35 patients studied, and low (mean -0.13 +/- 0.02%, range 0.02-0.36%) in 20 of 35 patients. All patients with a normal or increased percentage of CD34+ cells were ultimately diagnosed with hMDS based on the detection of clonal cytogenetic abnormalities or progression to refractory anemia with excess blasts/acute myeloid leukemia. All patients with low marrow CD34+ cell numbers met standard clinical criteria for AA and have not demonstrated neoplastic transformation with follow-up. Quantification of marrow CD34+ cells may serve as an important tool for distinguishing between AA and hMDS.     

Expression of FLIP(Long) and FLIP(Short) in bone marrow mononuclear and CD34+ cells in patients with myelodysplastic syndrome: correlation with apoptosis.

Several apoptosis-inducing systems, including Fas/Fas ligand and TNF-related apoptosis-inducing ligand (TRAIL) and its receptors, are upregulated in myelodysplastic syndrome (MDS). FLIP (FLICE (FAS-associated death-domain-like IL-1beta-converting enzyme)-inhibitory protein)) was identified as an inhibitor of FAS and TRAIL signals. Here, we characterized FLIP(Long) (FLIP(L)) and FLIP(Short) (FLIP(S)) expression in bone marrow mononuclear cells (BMMNCs) and in CD34+ cells of 29 MDS patients, and in 17 normal volunteers. The expression was correlated with apoptotic indices. In CD34+ cells, FLIP(L) levels were higher among normal individuals than in MDS patients (P=0.04). Among total BMMNC, FLIP(L) levels also tended to be higher in normal subjects than in MDS patients, although this difference was not significant (P=0.71). FLIP(L) levels in CD34+ cells were negatively correlated with apoptosis in both normal and MDS marrows (P=0.03). FLIP(Short) RNA expression was higher in MDS patients than in normal controls in both BMMNC (P=0.03) and CD34+ cells (P=0.08). In contrast to FLIP(L), FLIP(St) levels were positively correlated with apoptosis. At the protein level FLIP was most readily detectable in patients with high blast counts. The data suggest that FLIP(L) and FLIP(S) are differentially regulated, and that the relative levels of both isoforms play a role in the regulation of apoptosis in MDS.     

Multipotent and committed CD34+ cells in bone marrow transplantation.

In order to study the role of CD34+ cells in hematological recovery following bone marrow transplantation (BMT), bone marrow cells stained with HPCA-1 (CD34) and MY-9 (CD33) monoclonal antibodies were analyzed by using a fluorescence-activated cell sorter on or about days 14 and 28, as well as at later times, following BMT in 6 recipients. Single cell cultures of CD34+ cells were also performed to evaluate their in vitro hematopoietic function. CD34+ cells were detectable in bone marrow cells on day 14. More than 80% of CD34+ cells co-expressed the CD33 antigen, and macrophage (Mac) colony-forming cells predominated among total colony-forming cells of CD34+ cells. In normal bone marrow cells, CD34+, CD33+ cells amounted to about 40% of CD34+ cells, and the incidences of erythroid bursts, granulocyte/macrophage (GM) colonies, and Mac colonies were similar to each other. After more than 10 weeks, CD34+, CD33- cells gradually recovered, as erythroid burst colony-forming cells increased following GM colony-forming cells. This phenomenon was well-correlated with the time course of peripheral blood cell recovery. CD34+, CD33+ cells as committed progenitors and CD34+, CD33- cells as multipotent stem cells have distinctive biological behaviors in BMT.     

Oxidative DNA damage in bone marrow cells of patients with low-risk myelodysplastic syndrome

Bone marrow aspirates of 19 patients with low-risk myelodysplastic syndromes (MDS) and 14 control subjects were collected in order to assess the level of oxidative DNA damage. Glycophorin A positive and negative cells separated by miniMACS magnetic cell sorting were subjected to single cell gel electrophoresis (comet assay) combined with enzymes of base excision repair (endonuclease III and formamido-pyrimidine-glycosylase) that specifically recognize oxidized nucleotides. Compared to controls, MDS patients exhibited a significant increase of oxidative damage to DNA which could contribute to genomic instability and disease progression.     

Evaluation of CD7 and terminal deoxynucleotidyl transferase (TdT) expression in CD34+ myeloblasts from patients with myelodysplastic syndrome

There is an emerging use of flow cytometry to evaluate patients with myelodysplastic syndrome (MDS). We have studied CD7 and TdT expression in the CD34+ myeloid blast cell population in 55 bone marrow samples of patients with MDS. CD7 and/or TdT were detected in 38 out of 55 patients (69%). CD7 expression was not related to other bad prognosis data but conversely, we found an association between TdT+ CD34 myeloblasts and high-risk MDS patients according to the International Prognostic Scoring System. Therefore, CD7 and TdT may help to establish the diagnosis of MDS and, TdT expression also seems to be a useful marker in distinguishing risk groups.     

CD44 and adhesion of normal and leukemic CD34+ cells to bone marrow stroma

CD44 has long been implicated in the interaction between hematopoietic progenitors and bone marrow stroma. More recently it has become apparent that CD44 antibodies cannot only inhibit CD44 mediated adhesion to hyaluronic acid and cellular ligands but can stimulate adhesion to these ligands. The mechanism involved in CD44 antibody stimulated adhesion to cellular layers is still not known. While adhesion of T cells to keratinocytes is integrin mediated it appears that adhesion of hematopoietic progenitors to bone marrow stromal layers is the result of an antibody induced conformational change in the CD44 molecule similar to that seem for the augmentation of hyaluronic acid binding by some CD44 antibodies. The ligand for CD44 involved in this binding has not been identified but it does not appear to be hyaluronic acid.     

Flow cytometric analysis of the expression of Fas/Fasl in bone marrow CD34+ cells in myelodysplastic syndromes: relation to disease progression

The role of apoptosis in the pathobiology of myelodysplastic syndromes (MDS) remains controversial. We studied the expression of CD95 and CD95L in CD34+ cells of patients with newly diagnosed MDS by flow cytometry, and examined the relation between this expression and FAB and WHO types, total number of CD34+ bone marrow (BM) cells and the degree of peripheral cytopenias. The patients with refractory anemia (RA) and sideroblastic anemia showed CD34+ cells in numbers comparable to normal donors, but had a higher percentage of CD95/CD34 and CD95L/CD34 positive cells. An inverse correlation was found between these cells and the total CD34+ cells. This was also observed when only patients with RA were analyzed. In RAEB, however, CD95/CD95L expression correlated with CD34+ cells but not with the percentage of BM blasts. After classification by the WHO proposal, the patients with refractory cytopenias with multilineage dysplasia showed features intermediary between RA and RAEB. No significant correlation was seen between the expression of CD95/CD95L and the peripheral blood counts. These results are in keeping with the hypothesis that, as the number of MDS precursors increases during disease progression they become less succeptible to apoptosis.     

CD34+ cells from acute myeloid leukemia, myelodysplastic syndromes, and normal bone marrow display different apoptosis and drug resistance-associated phenotypes.

Myelodysplastic syndromes and acute myeloid leukemia (AML) are heterogeneous disorders in which conflicting results in apoptosis and multidrug resistance (MDR) have been reported. We have evaluated by multiparameter flow cytometry the expression of apoptosis- (APO2.7, bcl-2, and bax) and MDR-related proteins [P-glycoprotein (P-gp), multidrug resistance protein (MRP), and lung resistance protein (LRP)] specifically on bone marrow (BM) CD34+ cells, and their major CD32-/dim and CD32+ subsets, in de novo AML (n=90), high-risk myelodysplastic syndrome (n=9), and low-risk myelodysplastic syndrome (n=21) patients at diagnosis, and compared with normal BM CD34+ cells (n=6). CD34+ myeloid cells from AML and high-risk myelodysplastic syndrome patients displayed higher expression of bcl-2 (P <0.0001) and lower reactivity for APO2.7 (P=0.002) compared with low-risk myelodysplastic syndrome and normal controls. Similar results applied to the two predefined CD34+ myeloid cell subsets. No significant differences were found in the expression of P-gp, MRP, and LRP between low-risk myelodysplastic syndrome patients and normal BM, but decreased expression of MRP (P <0.03) in AML and high-risk myelodysplastic syndromes and P-gp (P=0.008) in high-risk myelodysplastic syndromes were detected. Hierarchical clustering analysis showed that low-risk myelodysplastic syndrome patients were clustered next to normal BM samples, whereas high-risk myelodysplastic syndromes were clustered together and mixed with the de novo AML patients. In summary, increased resistance to chemotherapy of CD34+ cells from both AML and high-risk myelodysplastic syndromes would be explained more appropriately in terms of an increased antiapoptotic phenotype rather than a MDR phenotype. In low-risk myelodysplastic syndromes abnormally high apoptotic rates would be restricted to the CD34- cell compartments.     

Prognostic value of circulating CD34+ cells in myelodysplastic syndromes

We studied circulating (C)CD34(+) cells by flow cytometry in 96 patients with myelodysplastic syndromes (MDS) at diagnosis, and in a subset of 35 cases during follow-up. CCD34(+) counts were stratified within both International Prognostic Scoring System (IPSS) and World Health Organization (WHO) categories. Counts >10/microl were associated with poorer leukemia-free survival, a prognostic value for evolution independent from that of WHO, and a higher progression probability within intermediate-risk IPSS and WHO classes. When serial measurements were performed, counts >10/microl more frequently correlated to evolution. Separating newly diagnosed patients on the basis of 10/microl cut-off of circulating CD34(+) cells retains prognostic utility, especially in intermediate-risk MDS.     

骨髓增生异常综合征患者外周血循环CD34+细胞计数的临床研究

目的 探讨骨髓增生异常综合征（MDS）患者外周血循环CD34+细胞计数在疾病分型及预后中的意义。方法 流式细胞仪测定16例健康者、40例MDS患者外周血循环CD34+细胞占有核细胞的百分比（简称CD34+细胞百分比）和绝对细胞数。依据WHO MDS诊断标准、染色体核型以及国际预后积分系统（IPSS）将MDS患者分别划分为RA／RARS／RCMD 组和RAEB Ⅰ／RAEB Ⅱ组,染色体良好组、中间组、不良组,中危Ⅰ组、中危Ⅱ组、高危组。结果MDS患者外周血循环CD34+细胞百分比、绝对数分别为0.67％和17.24个／μl,健康者分别为0.03％和1.63个／μl,两者比较差异有统计学意义（P＜0.01）。MDS患者中,RA／RARS／RCMD组CD34+细胞百分比及绝对数分别为0.05％和3.50个／μl,RAEBⅠ／RAEBⅡ组分别为3.09％和81.95个／μl（P＜0.01）;染色体良好组CD34+细胞百分比及绝对数分别为0.05％和3.50个／μl,中间组为1.29％和18.23个／μl,不良组为3.09％和133.10个／μl,随着不良核型的出现,CD34+细胞百分比及绝对数依次增高（P＜0.05）;中危Ⅰ组CD34+细胞百分比及绝对数分别为0.05％和3.50个／μl,中危Ⅱ组为1.57％和35.55个／μl,高危组为8.15％和192.05个／μl,随着IPSS分值的递增,CD34+细胞百分比及绝对数逐渐增高（P＜0.01）。结论 MDS患者外周血循环CD34+细胞计数存在异常增高现象,其计数水平的检测有助于MDS的分型和预后判断。