单个核细胞计数对异基因外周血干细胞移植后造血重建的预测研究

目的探讨单个核细胞(MNC)计数作为造血干(祖)细胞含量的独立指标预测异基因外周血干细胞移植(allo-PBSCT)后造血重建的可行性。方法将暨南大学附属第一医院血液科2000年1月至2008年12月120例allo-PBSCT患者分为MNC组(83例)和CD34+细胞组(37例),MNC组以≥4×108/kg为采集目标,CD34+细胞组以≥4×106/kgCD34+细胞为采集目标。比较两种计数指标对造血重建和供者采集次数的影响,并分析不同MNC剂量对造血重建的影响。结果MNC组受者输入MNC的中位数为6.81×108/kg,CD34+细胞组受者输入CD34+细胞的中位数为5.05×106/kg;两组造血重建率均为100%;两组中性粒细胞植活的中位时间均为移植后第11天(P0.05),血小板植活的中位时间均为移植后第12天(P0.05);两组供者1次采集率分别为100%和37.84%(P0.05);MNC组中HLA全相合与不全相合移植受者中性粒细胞植活的中位时间分别为移植后第11天和移植后第12天(P0.05),血小板植活的中位时间分别为移植后第12天和移植后第14天(P0.05);MNC剂量在(3～5.99)×108/kg递增时,剂量与造血重建呈正相关,而MNC剂量在达到6×108/kg后递增,则并未使植活时间随之进一步缩短。结论MNC计数单独作为造血干(祖)细胞含量的计数指标,不仅能可靠预示allo-PBSCT(包括HLA全相合与不全相合移植)后造血重建,其植活率和植活速度可与CD34+细胞相比拟,而且其供者1次采集率(100%)显著高于后者(37.84%),allo-PBSCT时MNC计数可取代CD34+细胞作为造血干(祖)细胞含量的独立指标。     

CD34+CD49d+细胞输入量对儿童急性白血病无关脐血移植的影响

目的研究CD34+CD49在d+细胞输入量在无关脐血移植治疗儿童急性白血病中对造血干细胞植入、中性粒细胞恢复时间的影响.方法用流式细胞术分析复苏后的CD34+CD49d+细胞数,并对17例儿童急性白血病在无关脐血移植后的中性粒细胞恢复时间进行分析.结果移植后17例患者中性粒细胞＞0.5×109/L的时间为11～32 d(中位数为17 d).CD34+CD49d+细胞输入量为(10.20～527.41)×104/kg(中位数为120.01×104/kg).中性粒细胞恢复时间与CD34+CD49d+细胞输入量呈负相关(γ＝-0.631,P＜0.05).结论无关脐血移植的CD34+CD49d+细胞输入量与造血于细胞的植入和造血重建有关.     

肿瘤患者外周血干细胞动员过程中CD+34细胞的动态变化及意义

为观察肿瘤患者 CD+ 34 细胞数量在动员过程中的动态变化 ,确定采集干 /祖细胞的最佳时机 ,采用环磷酰胺 (CTX)联合粒细胞集落刺激因子 (G- CSF)对 2 1例肿瘤患者进行造血干 /祖细胞动员。动员过程中 ,每天进行血细胞计数 ,于前期、极期、恢复早期、恢复期计数外周血 CD+ 34 细胞、白细胞 (WBC)、单核细胞 (MNC)、血小板(Plt)。结果显示 ,不同患者出现极期、恢复早期、恢复期的时间差异较大。与前期相比 ,极期 CD+ 34 明显降低(P<0 .0 5 ) ,恢复期则显著增加 (P<0 .0 1)。WBC、MNC、Plt变化均与 CD+ 34 细胞变化呈显著正相关 (r分别为 0 .99、0 .82 7、0 .886 ,P均 <0 .0 1)。提示在 WBC>5 .0× 10 9/ L时采集外周血造血干细胞 (PBSC)较合适 ,MNC>1.5×10 9/ L时采集 PBSC较理想 ,监测 Plt计数变化 ,亦可为确定采集干细胞时间提供有意义的信息     

CD+34细胞与支气管哮喘

CD34是一种阶段特异性的白细胞分化抗原,选择性地表达于早期造血干/祖细胞表面.近年研究发现CD34阳性(CD+34)细胞在哮喘患者骨髓、外周血及肺组织局部明显增多,它可能参与哮喘时特异性嗜酸粒细胞性气道炎症的形成.深入研究CD+34细胞在哮喘中的作用有助于阐明该疾病的发生机制,并为其治疗拓展新的思路.     

异基因外周血造血干细胞移植治疗难治性白血病(附1例报告)

对 1例难治性急性粒 -单细胞白血病 (AML - M4 b)患者施行异基因外周血造血干细胞移植 (allo-PBSCT ) ,以 Cy/ TBI方案预处理后 ,输注 HL A完全相合的同胞供者经 G- CSF动员的外周血单个核细胞(PBMNCs) 9.0× 10 8/ kg,其中 CD34 细胞 6 .2 5× 10 6 / kg;移植物抗宿主病 (GVHD)的预防用 Cs A MTX方案。结果 : 15天时 ,外周血中性粒细胞 >0 .5× 10 9/ L,血小板 >5 0× 10 9/ L; 30天时 ,外周血三系均完全恢复正常。仅有 度皮肤 GVHD发生。认为对于难治性白血病 ,如有 HL A相合供者 ,应及早行异基因造血干细胞移植 (allo-HSCT)特别是 allo- PBSCT,具有受者造血与免疫功能重建快等优点     

供体CD+4CD+25T细胞及调控基因FOXP3在急性移植物抗宿主病中的作用

目的 探讨供体CD+4CD+25T细胞亚群、FOXP3调控基因的表达与受者移植物抗宿主病(GVHD)的相关性.方法 (1)30例异基因造血干细胞移植(allo-HSCT),采用免疫荧光标记和流式细胞术检测并比较供体粒细胞集落刺激因子(G-CSF)动员前外周血、动员后采集物CD+4CD+25T细胞亚群比例,随访异基因移植后GVHD的发生率和严重程度.(2)应用RT-PCR技术检测供体FOXP3基因表达情况,分析其与GVHD、疾病复发的相关性.结果 (1)所有患者均获造血重建,粒细胞绝对数(ANC)≥0.5×109/L的中位时间为14(12～15)d,PLT≥20×109/L为18(15～25)d.30例allo-HSCT,中位随访时间12.8(8～16)个月,Ⅰ～Ⅳ度急性GVHD分别为3、4、3、5例.慢性GVHD 6例.(2)供体G-CSF动员前外周血、动员后采集物CD+4CD+25T细胞亚群分别为(2.67±0.38)%、(5.01±1.33)%,两者相比差异无统计学意义(P＞0.05).(3)移植后无急性GVHD组、Ⅰ～Ⅱ度急性GVHD组、Ⅲ～Ⅳ度急性GVHD组供体CD+4CD+25T细胞亚群分别为(5.05±1.34)%、(4.17±1.73)%、(1.98±1.10)%.其中Ⅰ～Ⅱ度急性GVHD组与Ⅲ～Ⅳ度急性GVHD组相比差异有统计学意义(P=0.04),无急性GVHD组与Ⅲ～Ⅳ度急性GVHD组相比差异有统计学意义(P=0.002).(4)30例allo-HSCT,7例FOXP3基因表达阳性,5/7例移植后无急性GVHD,其中3例移植后复发,另2/7例移植后Ⅰ度急性GVHD,Ⅱ～Ⅳ度急性GVHD患者FOXP3均不表达.结论 (1)供体CD+4CD+25T细胞亚群比例与受者急性GVHD的发生具有一定的相关性,提高供体CD+4CD+25T细胞数量有望减低移植后急性GVHD发生率.(2)供体移植物FOXP3基因表达阳性,与移植后有无严重急性GVHD发生存在一定相关性.     

同胞人类白细胞抗原相合骨髓和外周血造血干细胞混合移植后造血重建分析

,P=0.065).以移植物中CD34+细胞的中位数为界,输入CD34+数量＞2.45×106/ks的78例患者中性粒细胞、血小板植入的时间分别为14.5 d和11 d显著快于CD34+细胞数量≤2.45×106/kg的79例患者(16 d和14 d)(P值分别为0.021、0.010).结论 移植物中CD34+细胞是同胞HLA相合骨髓和allo-HSCT后中性粒细胞和血小板植入的影响因素,病程也是血小板植入的一个影响因素.     

系统性红斑狼疮患者骨髓CD34+细胞表面标志及与病情活动的相关性分析

目的研究系统性红斑狼疮(SLE)患者骨髓CD34+细胞表面标志的变化,了解SLE患者造血干细胞是否存在异常。方法应用流式细胞术CD45/SSC设门分析10例SLE患者和10例正常人骨髓CD34+细胞CD90、CD117、CD123、CD164、CD166、CD95(FAS)、FAS-L、人类白细胞抗原(HLA)-DR等表面分子的表达及其与病情活动指标的相关性。结果活动期SLE患者骨髓CD34+细胞比例(1.5±0.4)%,明显低于正常人(2.3±0.8)%,P<0.01;非活动期患者(2.0±0.4)%与正常人相比差异无统计学意义。SLE患者CD34+、CD95+的表达明显高于正常人[(48.3±10.6)%vs(24.3±11.1)%,P<0.05],患者CDl23和CDl66也明显高于正常人[(45±22)%vs(20±4)%,P<0.05];[(31±20)%vs(11±6)%,P<0.05]。其余表面标志的表达与正常人相比差异无统计学意义。CDl23表达率与患者外周血白细胞计数负相关(r=-0.700,P< 0.05),与SLE疾病活动指数(SLEDAI)评分无相关性。CD166表达与SLEDAI(r=0.472,P<0.05),血清C3 (r=-0.712,P<0.01),尿蛋白定量(24h)(r=0.558,P<0.05)显著相关。结论SLE患者骨髓CD34+细胞CD95、CDl23、CDl66的表达率增加,CDl23的表达率与外周血白细胞计数显著负相关:CDl66的表达率与SLEDAI评分、24h尿蛋白呈显著正相关,与血清C3呈显著负相关,CDl66可能是一个新的SLE疾病活动性标志。     

中药组方对人外周血造血干细胞的影响

目的探讨中药组方对健康供者外周血造血干细胞的影响。方法 34例志愿健康供者应用中药组方,1次/d,1袋/次,服用1个月。采用血细胞计数仪检测外周血中单个核细胞数,流式细胞仪检测CD34~+细胞数的变化;通过RT-PCR法观察服药前后外周血造血细胞生长因子白细胞介素(IL)-3、粒细胞集落刺激因子(GM-CSF)的mRNA半定量表达情况。结果与服药前相比,外周血单核细胞、CD34~+细胞数明显增高(P0.01),服药后IL-3、GM-CSF mRNA的半定量表达水平与服药前相比差异显著(P0.01)。结论中药组方可能通过增强造血生长因子IL-3、GMCSF mRNA表达水平,刺激造血细胞分化成熟,有效动员外周血造血干细胞,供者无明显的不良反应。     

类风湿关节炎患者外周血CD34+造血干/祖细胞的检测及其意义

目的 探讨类风湿关节炎(RA)外周血造血干/祖细胞(HSC/HPC)的数量及细胞膜CD34平均荧光强度(MFI)变化及其与临床指标的关系,以期阐明其在RA中的意义.方法 收集34例RA患者和16名健康对照者外周血,利用单克隆抗体标记CD34+细胞,流式方法测定CD34+HSC/HPC所占外周血淋巴细胞的比例及膜CD34的MFI,分析其与外周血细胞计数、疾病活动病程和药物应用的关系.数据分析采用t检验和方差分析,相关性分析采用Pearson相关分析.结果 ①RA患者CD34+细胞在外周血中淋巴细胞中所占的比例比健康人偏低[分别为(0.13±0.09)%和(0.38±0.21)%,P＜0.05],但两者所占外周血淋巴细胞的比例均低于0.5%;但MFI偏高(分别为57±33和31±11,P＜0.05).②RA患者CD34+细胞在外周血淋巴细胞中所占的比例与外周血红细胞计数、血红蛋白浓度呈正相关性,和C反应蛋白呈负相关;其MFI与健康评价问卷表(HAQ)评分、X线分期呈正相关,与血小板计数呈负相关.③RA患者CD34+细胞在外周血淋巴细胞中所占比例的降低程度以及MFI与疾病的活动性、病程和用药情况无明显相关性(P＞0.05).结论 造血干细胞可能在RA的发病机制中起作用.     

Influence of the different CD34+ and CD34- cell subsets infused on clinical outcome after non-myeloablative allogeneic peripheral blood transplantation from human leucocyte antigen-identical sibling donors

Currently, no information is available regarding the influence of the different CD34+ cell subsets infused on the haematopoietic recovery, following non-myeloablative allogeneic peripheral blood stem cell transplantation (allo-PBSCT). We have explored, in a group of 13 patients receiving non-myeloablative allo-PBSCT from human leucocyte antigen-identical sibling donors, the influence of the total dose of CD34+ haematopoietic progenitor cells (HPC) infused, compared with that of the different CD34+ HPC and CD34- leucocyte subsets in the leukapheresis samples, on both engraftment and clinical outcome. The overall numbers of total CD34+ HPC (P = 0.002) and myelomonocytic-committed CD34+ HPC infused (P = 0.0002) were strongly associated with neutrophil recovery (> 1 x 109 neutrophils/l), the latter being the only independent parameter influencing neutrophil recovery. Regarding long-term engraftment, only the number of immature CD34+ HPC infused/kg correlated with the duration of hospitalization in the first 2 years after discharge (r = -0.75, P = 0.005). Both the overall amount of CD34+ HPC and the number of myelomonocytic CD34+ HPC infused showed a significant influence on the risk of graft-versus-host disease (GVHD). Thus, the overall probability of GVHD was 100%vs 25% for patients receiving >/= 5 x 106 CD34+ HPC or >/= 3.5 x 106 of myelomonocytic-committed CD34+ HPC vs lower doses (P = 0.013). None of the other CD34+ and CD34- cell subsets analysed correlated with development of GVHD. In summary, our results suggest that in non-myeloablative allo-PBSCT, high numbers of CD34+ HPC, especially the myelomonocytic-committed CD34+ progenitors, lead to rapid neutrophil engraftment. However, they also strongly impair clinical outcome by increasing the incidence of GVHD.     

Subsets of CD34+ and early engraftment kinetics in allogeneic peripheral SCT for AML

This study aimed to identify which graft product subset of CD34+ cells might be the most predictive of early hematopoietic recovery following allogeneic peripheral SCT (allo-PBSCT). The relationship between the number of 'mature' subsets of CD34+ cells (CD34+/CD33+, CD34+/CD38+, CD34+/DR+ and CD34+/CD133-) and 'immature' subsets of CD34+ cells (CD34+/CD33-, CD34+/CD38-, CD34+/DR- and CD34+/CD133+) and early neutrophil and platelet engraftment were studied in a homogeneous series (for disease, pre transplant chemotherapy, conditioning regimen and GVHD prophylaxis) of 30 AML patients after allo-PBSCT from HLA-identical siblings. In our experience, the total CD34+/CD133+ cell number was inversely correlated with the days required for the recovery of 0.5 x 10(9)/l neutrophils (r=or-0.82, P=0.02) and platelets of 20 x 10(9)/l (r=or-0.60, P=0.06); this correlation was better than the total CD34+ cell dose and neutrophil (r=or-0.70, P=0.04) and platelet engraftment (r=or-0.56, P=0.07). We suggest that a high number of CD34+/CD133+ PBSC may be associated with faster neutrophil and platelet recovery; these findings may help to predict the repopulating capacity of PBSC in patients after allo-PBSCT, especially when a relatively low number of CD34+ cells is infused.     

CD34+ cell dose and hematologic recovery in allogeneic peripheral blood stem cell transplantation

Allogeneic peripheral blood stem cell transplantation (Allo-PBSCT) has been performed as an alternative to bone marrow transplantation (BMT). Here we report poor mobilization with granulocyte-colony stimulating factor (G-CSF) and engraftment kinetics in Allo-PBSCT. Sixteen patients (aged 6-61 yr, median 34 yr) received allogeneic peripheral blood stem cells from related donors (aged 15-68 yr, median 37 yr) after myeloablative therapy. Nine of the patients had standard-risk disease and 7 had high-risk disease. The donors received G-CSF at a dose of 10 micrograms/kg/day by subcutaneous injection for 4 to 6 days. Peripheral blood stem cells were subsequently collected in 1 to 3 aphereses and infused immediately. All patients received G-CSF after transplantation. Fifteen patients underwent Allo-PBSCT and one underwent Allo-PBSCT plus BMT. The mean number of CD34+ cells infused in the 15 Allo-PBSCT patients was 6.32 x 10(6)/kg (range 1.28-14.20). The outcomes were compared with 9 identically treated patients who underwent Allo-BMT. The median times until engraftment for neutrophils > 500/microliter and platelets > 20,000/microliter were 14 (range 10-17) and 15 (range 11-50) days in the Allo-PBSCT group and 17 (range 13-29) and 20 (range 16-160) days in the Allo-BMT group, respectively (p = 0.0177 and p = 0.003). Three donors were considered to have poor mobilization (< 2 x 10(6) CD34+ cells/kg of the recipient); two of them yielded 1.28 and 1.78 x 10(6) CD34+ cells/kg in 3 apheresis procedures. The patients who received cells from these donors showed prompt neutrophil engraftment, but one showed delayed platelet engraftment and another died of grade IV acute GVHD before reaching 20,000 platelets/microliter. An additional bone marrow harvest was necessary from one donor because of poor mobilization(0.17 x 10(6) CD34+ cells/kg). Thus, Allo-PBSCT results in more rapid engraftment. It will be necessary to clarify the minimum CD34+ cell dose for complete engraftment in a larger series of trials.     

Early and long-term engraftment after autologous peripheral stem cell transplantation in acute myeloid leukemia patients

This study aimed to identify which subset of CD34+ cells might be the most predictive of early and long-term hematopoietic recovery following autologous peripheral blood stem cell (PBSC) transplantation (PBSCT) in adult acute myeloid leukemia (AML) patients. The relationships between the number of 'mature' subsets of CD34+ cells (CD34+/CD33+, CD34+/CD38+, CD34+/DR+ and CD34+/CD90-) and 'immature' subsets of CD34+ cells (CD34+/CD33-, CD34+/CD38-, CD34+/DR- and CD34+/CD90+) and early and long-term hemoglobin, neutrophil and platelet counts were studied in a homogeneous series (for disease, pre-transplant chemotherapy, mobilization chemotherapy, conditioning regimen) of 26 AML patients after autologous PBSCT. Cell counts were performed before and after cryopreservation, but only after thawing were the cell counts used for correlation with early and long-term engraftment. The number of CD34+/CD38- cells infused correlated with the neutrophil (r = 0.88, p < 0.005) and platelet counts (r = 0.67, p < 0.05) at 12 months after PBSCT. This correlation was better than that for the total CD34+ cell dose at 12 months (r = 0.36, p = 0.09 for neutrophil count and r = 0.48, p = 0.06 for platelets count). The number of CD34+/CD90+ cells was also correlated with the platelet counts at 6 (r = 0.70, p < 0.05) and 12 months (r = 0.80, p = 0.005) after PBSCT. This correlation was better than the total dose of CD34+ cells at 6 (r = 0.31, p = 0.3) and 12 months (r = 0.48, p = 0.06) for the platelet counts. CD34+ subset analysis suggests that for early engraftment the total number of CD34+ cells infused is more strongly correlated than the CD34+ subsets, whereas the CD34+/CD38- and CD34+/CD90+ subsets may be associated with sustained long-term neutrophil and platelet engraftment. These findings may help to predict the repopulating capacity of PBSCs in AML patients after autologous PBSCT, especially when a relatively low number of CD34+ cells is infused.     

Impact of CD34 subsets on engraftment kinetics in allogeneic peripheral blood stem cell transplantation

Our objective was to evaluate, probably for the first time, the impact of CD34 subsets on engraftment kinetics in allogeneic PBSC transplantation (PBSCT). PBSC graft components were analyzed in 62 cases for the absolute count/kg of total CD34+ and the following subsets: DR- and +, CD71+/-, CD38+/-, CD33+/- and CD61+/-. Time to ANC >0.5 and >1 x 10(9)/l and platelets >20 and >50 x 10(9)/l was reported. The median value for each parameter was used to discriminate rapid from slow engraftment. Four parameters showed significant predictive power of early neutrophil engraftment, namely CD34+ /DR- (P = 0.002), CD34+/38- (P = 0.02), CD34+/CD61- (P = 0.04) and total CD34+ cell dose (P = 0.04). Four parameters showed significant predictive power of early platelet engraftment, namely CD34+/CD61+ (P = 0.02), CD34+ /CD38- and total CD34+ cell dose (P = 0.04) and CD34+ /CD71- (P = 0.05). Comparing patients who received > to those who received < the threshold dose(s), only CD34+ /CD38- lost its significance for neutrophil engraftment; and only CD34+ /CD61+ retained its significance for platelet engraftment (P = 0.03); furthermore, the former group required significantly fewer platelet transfusions (P = 0.018). We concluded that in allogeneic PBSCT, the best predictor of early neutrophil engraftment is the absolute CD34+ /DR- and for early platelet engraftment is the absolute CD34+ /CD61+ cell dose.     

CD34+/CD90+ cells infused best predict late haematopoietic reconstitution following autologous peripheral blood stem cell transplantation

This study aimed to identify which graft product subset of cells might be the most predictive of late haematopoietic recovery (three to 12 months) following autologous peripheral blood stem cell transplantation (PBSCT). The relationships between the numbers of reinfused CD34+ cells and their immature subsets such as CD34+/CD90+, CD34+/AC133+, CD34+/CD38- and CD34+/HLA-DR- cells, and haemoglobin, white blood cell (WBC) and platelet counts at 3, 6, 9 and 12 months after PBSCT, were studied in 25 patients with haematological and solid malignancies. The total CD34+ cell number, as well as CD34+/CD90+ and CD34+/AC133+ cell numbers, correlated with platelet counts at 3, 6, 9 and 12 months after PBSCT, but the CD34+/CD90+ cells infused best predicted platelet recovery during the first 12 months after PBSCT (P < 0.0238 at any time-point). The CD34+/AC133+ cell dose also correlated with WBC counts at 3 months post PBSCT. In addition, all patients receiving more than 80 x 10(4) CD34+/CD90+ cells/kg showed platelet counts greater than 100 x 10(9)/l at all points after PBSCT, suggesting that this value of the CD34+/CD90+ cells infused was a threshold dose for durable haematopoietic engraftment after PBSCT.     

Analysis of CD34+ cell subsets in stem cell harvests can more reliably predict rapidity and durability of engraftment than total CD34+ cell dose, but steady state levels do not correlate with bone marrow reserve

In peripheral blood stem cell transplantation (PBSCT), the number of CD34+ cells transplanted has been shown to correlate well with both rapidity and durability of engraftment. However, it is clear that engraftment does not necessarily correlate with total CD34+ cell numbers in some patients. Consequently, there is increasing interest in evaluating the role of CD34+ subsets in haemopoietic recovery as a more accurate marker of harvest quality. We analysed the numbers of CD34+ cell subsets, namely Thy-1+, L-Selectin+ and CD38-, and correlated this with engraftment in 86 patients undergoing PBSCT. Adequate engraftment was defined as being a platelet count greater than 50 x 10(9)/l and a neutrophil count greater than 1.0 x 10(9)/l. CD34+L-Selectin+ provided the best prediction of engraftment rapidity, although the improvement over total CD34+ cell dose was minor. Only the dose of CD34+Thy-1+ cells transplanted correlated with durable engraftment. The probability of adequate 3-month engraftment increased with the dose of CD34+ cells transplanted, but 10% of patients receiving > 5 x 10(6)/kg still showed poor engraftment at 3 months. However, all patients receiving > 2.5 x 10(5)/kg CD34+Thy-1+ showed adequate engraftment at this time point. We also demonstrated that CD34+Thy-1+ progenitors were restricted to the bone marrow under normal conditions and, during stem cell mobilization, their kinetics generally paralleled total CD34+ numbers.     

Factors predicting engraftment of autologous blood stem cells: CD34+ subsets inferior to the total CD34+ cell dose.

Data were analyzed on 178 consecutive patients (median age 43 years) who underwent autologous blood stem cell transplantation (ABSCT) at a single institution to determine if CD34+ subsets (CD34+38-, CD34+33-, CD34+33+, CD34+41+) or various clinical factors affect hematopoietic engraftment independent of the total CD34+ cell dose/kg. Using Cox proportional hazards models, the factors independently associated with rapid neutrophil engraftment were higher CD34+ dose/kg, use of G-CSF post-ABSCT, and conditioning regimen (single-agent melphalan +/- TBI slower). Factors independently associated with rapid platelet engraftment were higher CD34+ cell dose/kg, higher ratio of CD34+33-/total CD34+ cells infused, conditioning regimen (mitoxantrone, vinblastine, cyclophosphamide faster), and no CD34+ cell selection of the autograft. The CD34+ cell selection process seemed to deplete CD34+41+ cells to a greater extent than total CD34+ cells which may explain our observation that it resulted in slower platelet engraftment. In conclusion, the total CD34+ dose/kg was a better predictor of hematopoietic engraftment following ABSCT than the dose of any CD34+ subset. Platelet engraftment, however, was also influenced by the ratio of CD34+33-/total CD34+ cells for unmanipulated autografts, and possibly by the CD34+41+ dose for autografts manipulated by CD34+ selection. The use of CD34+ subsets requires further investigation in predicting engraftment of autografts which undergo ex vivo manipulation.     

An analysis of engraftment kinetics as a function of the CD34 content of peripheral blood progenitor cell collections in 692 patients after the administration of myeloablative chemotherapy

The CD34 antigen is expressed by committed and uncommitted hematopoietic progenitor cells and is increasingly used to assess stem cell content of peripheral blood progenitor cell (PBPC) collections. Quantitative CD34 expression in PBPC collections has been suggested to correlate with engraftment kinetics of PBPCs infused after myeloablative therapy. We analyzed the engraftment kinetics as a function of CD34 content in 692 patients treated with high-dose chemotherapy (HDC). Patients had PBPCs collected after cyclophosphamide based mobilization chemotherapy with or without recombinant human granulocyte colony-stimulating factor (rhG-CSF) until > or = 2.5 x 10(6) CD34+ cells/kg were harvested. Measurement of the CD34 content of PBPC collections was performed daily by a central reference laboratory using a single technique of CD34 analysis. Forty-five patients required a second mobilization procedure to achieve > or = 2.5 x 10(6) CD34+ cells/kg and 15 patients with less than 2.5 x 10(6) CD34+ cells/kg available for infusion received HDC. A median of 9.94 x 10(6) CD34+ cells/kg (range, 0.5 to 112.6 x 10(6) CD34+ cells/kg) contained in the PBPC collections was subsequently infused into patients after the administration of HDC. Engraftment was rapid with patients requiring a median of 9 days (range, 5 to 38 days) to achieve a neutrophil count of 0.5 x 10(9)/L and a median of 9 days (range, 4 to 53+ days) to achieve a platelet count of > or = 20 x 10(9)/L. A clear dose-response relationship was evident between the number of CD34+ cells per kilogram infused between the number of CD34+ cells per kilogram infused and neutrophil and platelet engraftment kinetics. Factors potentially influencing the engraftment kinetics of neutrophil and platelet recovery were examined using a Cox regression model. The single most powerful mediator of both platelet (P = .0001) and neutrophil (P = .0001) recovery was the CD34 content of the PBPC product. Administration of a post-PBPC infusion myeloid growth factor was also highly correlated with neutrophil recovery (P = .0001). Patients receiving high-dose cyclophosphamide, thiotepa, and carboplatin had more rapid platelet recovery than patients receiving other regimens (P = .006), and patients requiring 2 mobilization procedures versus 1 mobilization procedure to achieve > or = 2.5 x 10(6) CD34+ cells/kg experienced slower platelet recovery (P = .005). Although a minimal threshold CD34 dose could not be defined, > or = 5.0 x 10(6) CD34+ cells/kg appears to be optimal for ensuring rapid neutrophil and platelet recovery.     

Subsets of CD34+ hematopoietic progenitors and platelet recovery after high dose chemotherapy and peripheral blood stem cell transplantation.

BACKGROUND AND OBJECTIVE: Randomized clinical trials have shown that peripheral blood stem cell transplantations (PBSCT) with appropriate doses of CD34+ cells are associated with rapid, complete and sustained recovery of marrow functions. Nevertheless, in a minority af patients delayed platelet recovery may occur and it remains to be established whether analysis of transplanted CD34+ cell subsets may demonstrate correlation with this phenomenon. We studied a series of 80 consecutive transplanted patients with the aim of evaluating the effect of CD34+ stem cell numbers and, in a subgroup of 32 patients, the effect of the lineage specific subset numbers on time to platelet engraftment (i.e. time to platelet counts higher than 20x10(9)/L for two consecutive days without the need for platelet transfusions). DESIGN AND METHODS: Different clinical and paraclinical factors were examined in a multivariate analysis for effect on platelet engraftment in 80 patients. RESULTS: The number of CD34+ cells/kg infused was the most important factor predicting the time to platelet engraftment. Patients receiving more than 10x10(6) CD34+ cells/kg had prompt platelet engraftment. The majority of the patients (78%) received fewer than 10x10(3) CD34+ cells/kg and 17/62 (27%) of these patients experienced delayed platelet engraftment. In 32 patients receiving fewer than 10x10(6) CD34+ cells/kg we focused on the content of different lineage specific CD34+ subsets in the PBSC products. The most significant correlation was recognized for CD34+/CD61+ megakaryocytic cell number and platelet engraftment. An inverse correlation between the CD34+/CD38Eth subset and platelet engraftment was found, indicating that a high number of CD34+/CD38Eth in the PBSC product might increase the risk for delayed engraftment. These results were further confirmed by the observation that patients who experienced platelet engraftment after day 20 had significantly more CD34+/CD38Eth cells/kg infused than patients with fast engraftment. INTERPRETATION AND CONCLUSIONS: The number of total CD34+ cells/kg infused was the most important factor predicting time to platelet engraftment. CD34+ subset analysis in a subgroup of patients suggests that a high number of uncommitted progenitors may be associated with slower platelet recovery than transplantation with a higher fraction of more committed peripheral blood stem cells.