硫酸葡聚糖伍用G-CSF对小鼠外周血造血干细胞动员作用研究

研究了硫酸葡聚糖(DS)和粒细胞集落刺激因子(G-CSF)单独应用及联合应用对小鼠外周血造血祖细胞的动员作用。联合用药方式为小鼠连续5天静脉注射G-CSF10μg/d,第5天腹腔注射DS15mg/k 体重,DS给药后2小时检测外周血白细胞,单个核细胞和CFU-GM,结果发现应用DS和G-CSF及二者联合用药后,外周血白细胞比给药前分别增高了2.5,1.8和2.8倍,外周血单个核细胞比给药前分别增高了1.9,1.7和2.5倍。DS与G-CSF联合用药,可以使粒系祖细胞数量分别高于单独使用DS和G-CSF组的53.4％和15.3％,统计学处理有显著性意义(P<0.05)。结论提示,DS与G-CSF联合应用对外周血造血祖细胞的动员产生了协同作用,其机制可能在于二者动员的途径不同。     

rhG-CSF体内应用对骨髓和外周血造血干/祖细胞上CXCR-4表达的影响

为了观察rhG-CSF动员对外周血和骨髓造血干/祖细胞上CXCR-4表达的影响,应用三色荧光标记技术对动员前后骨髓和外周血中单个核细胞（MNC）和CD34＋细胞上CXCR-4的表达进行了测定.结果显示,G-CSF动员显著增加了外周血MNC及骨髓CD34＋细胞上CXCR-4的表达,骨髓MNC及外周血CD34＋细胞上CXCR-4的表达无变化,稳态骨髓（SS-BM）中CD34＋细胞比例与G-BM、G-PB中CD34＋细胞比例呈正相关,与采集到的骨髓及外周血中CD34＋细胞/公斤也具有良好的正相关性.结论：G-CSF体内应用后CD34＋细胞上CXCR-4表达的变化可能是动员机制的一部分,CXCR-4的高表达可能有利于MNC的植入,SS-BM中CD34＋细胞的含量可作为动员效果好坏的预测指标.     

七天IL-3预处理增强粒细胞集落刺激因子动员循环祖细胞的能力

使用粒细胞集落刺激因子(G-CSF)作为单一动员剂,来动员外周血祖细胞(PBPCs)做干细胞移植已越来越多地为人们所应用。对于已有造血功能障碍的病人来说,单用G-CSF的动员能力可能是不够的。作者过去的研究表明,在恒河猴用白介素3(IL-3)进行预处理后,能显著增强粒细胞巨噬细胞集落刺激因子(GM-CSF)     

G-CSF对供者外周血CD34+细胞黏附分子表达的影响

目的通过观察健康供者外周血CD34+细胞黏附分子表达的变化,探讨粒细胞集落刺激因子(G-CSF)动员的机制及其对供者的影响。方法应用流式细胞仪分析15名健康供者在接受G-CSF10μg.kg-1.d-1动员前(Pre-G)、动员d4和停止动员后7d(Pro-G)外周血CD34+细胞比例及其表面黏附分子非常延迟抗原-5(VLA-5,CD49e)和L-选择素(CD62L)的表达情况。结果G-CSF动员后供者外周血CD34+细胞比例较动员前增高5-10倍,停止动员后恢复至动员前水平。G-CSF动员后CD34+CD49e+细胞比例(97.74%)明显高于动员前(79.95%),停止动员后7d CD34+CD49e+细胞比例基本恢复至动员前水平;CD34+CD62L+细胞比例在G-CSF动员过程中无明显改变;CD34+细胞表面CD49e与CD62L的平均荧光强度于动员后呈减弱趋势,但无显著统计学意义。结论G-CSF动员后d4可显著增加供者外周血CD34+细胞比例,可致CD34+CD49e+细胞比例一过性增加,但不影响CD34+CD62L+细胞群的比例。     

G-CSF动员骨髓干细胞向缺血-再灌注肾脏归巢并促进肾脏修复的研究

目的 观察粒细胞集落刺激因子(G-CSF)是否可以有效动员骨髓干细胞进入外周血并向缺血-再灌注损伤肾脏归巢,提高肾脏修复的效能.方法 6周龄全身表达绿色荧光蛋白(GFP)的C57BL/6J转基因小鼠提供骨髓,6～8周龄同种无荧光标记的C57BL/6J小鼠20只作为骨髓受体.骨髓移植前,受体小鼠接受致死剂量的γ放射线137Cs照射,骨髓重建情况经流式细胞仪检测确认.骨髓重建完毕后所有小鼠均接受单侧肾脏缺血-再灌注损伤.实验动物分组:(1)对照组(n=10),术前3d至术后4d,皮下注射生理盐水,0.2 ml/d.(2)动员组(n=10),术前3d至术后4d,皮下注射人重组粒细胞集落刺激因子200μg/(kg·d).干细胞动员效果及向肾脏归巢情况经流式细胞仪检测鉴定.损伤1周后取肾脏标本行HE染色,评估肾小管损伤程度.损伤4周后通过组织切片免疫荧光组织化学方法观察并计数血管内皮细胞数.实验数据中计量资料以均数±标准差((x-)±s)表示,两组计量资料之间比较采用独立样本t检验.结果 G-CSF动员后,分别为Sca-1、c-Kit、CD29、CD34阳性的四群干细胞占外周血非红系细胞的比例均高于对照组(P＜0.05).损伤1周后,G-CSF动员组的缺血侧肾脏中,骨髓来源并且分别表达Sca-1、c-Kit、CD34的干细胞的比例均高于对照组(P＜0.05);肾小管损伤程度评分分值低于对照组(P＜0.05).损伤4周后动员组的肾脏中CD31阳性的内皮细胞数目高于对照组(P＜0.05).结论 (1)G-CSF可以有效动员骨髓干细胞进入外周血并向缺血肾脏归巢;(2) G-CSF动员可以提高肾脏修复的效能,减轻肾脏组织病理学损伤程度.     

经粒系集落刺激因子刺激外周血CD34~+细胞动员效果相关因素的考察

目的探讨粒系集落刺激因子(G-CSF)动员健康供者外周血造血干细胞效果的影响因素。方法对24例健康供者皮下注射G-CSF动员造血干细胞,检测外周血T淋巴细胞亚群和血常规数据。结果经G-CSF刺激后,外周血CD3+(%)、CD3+CD4+(%)、白细胞计数、血小板均明显升高(P0.05);而动员第4天、第5天、第6天骨有核细胞密度、CD34+细胞百分比无明显差别。经相关性分析,性别、年龄、体质量与CD34+细胞百分比呈负相关(P0.05),白细胞计数呈正相关(P0.01)。结论在一定范围内男性供者优于女性供者,年龄越小,体质量越轻,白细胞计数越高,经G-CSF动员的外周血造血干细胞CD34+细胞百分比越高。     

单次剂量给予CXCR4拮抗药AMD3100动员和采集CD34＋造血细胞

背景 AMD3100是一种选择性的CXCR4拮抗药，它能够快速地将骨髓中的CD34＋造血祖细胞动员到外周血，而且副作用很小。研究设计和方法为了进一步研究AMD3100对动员和采集CD34＋细胞的潜在临床作用，作者对正常自愿者进行了仅单独给予单次剂量AMD3100和AMD3100加一个标准的5天剂量的粒细胞集落刺激因子（GCSF）联合用药的研究。     

基质细胞衍生因子-1及其受体在G-CSF诱导的造血干/祖细胞动员中的作用

目的探讨基质细胞衍生因子-1（SDF-1）及其特异性受体CXCR4在G-CSF诱导的造血干／祖细胞（HSPC）动员中的作用。方法应用酶联免疫吸附实验（ELISA）、免疫组织化学、流式细胞术等方法检测健康供者稳态及G-CSF动员过程中骨髓、外周血SDF-1／CXCR4的变化，并应用SDF-1中和性抗体阻断BALB／c小鼠SDF-1信号通路，进一步验证SDF-1／CXCR4在动员中的作用。结果G-CSF动员前骨髓和外周血的SDF-1浓度分别为（7．23±0．66）μg/L和（5．43±0．35）μg／L，动员后分别为（5．88±1．03）μg／L和（5．42±0．52）μg/L。动员后骨髓SDF-1蛋白水平下降（P＜0．05），骨髓和外周血之间的SDF-1浓度梯度消失（P＞0．05）；稳态骨髓、动员后骨髓和动员后外周血的CD34^＋ CXCR4^＋细胞在CD34^＋细胞群中的比例分别为（40．98±21．56）％、（65．80±24．68）％和（27．54±26．03）％。动员后CXCR4在骨髓CD34^＋胞上表达增加（P＜0．05），而外周血CD34^＋细胞CXCR4表达降低（P＜0．05）。SDF-1中和性抗体可降低G-CSF动员的BALB／c小鼠外周血成熟白细胞和祖细胞集落数量（P＜0．05）。结论骨髓中SDF-1水平的降低以及CXCR4在HSPC上表达的下降促进了G-CSF介导的动员的发生。     

GW003对骨髓细胞体外形成粒-巨噬细胞集落能力的影响

本研究旨在观察重组人血清白蛋白-粒细胞集落刺激因子融合蛋白（GW003）对骨髓造血细胞体外形成粒系集落能力的影响。分别抽取正常恒河猴、缓解期和化疗中pLLL患者骨髓并分离有核细胞,分别加入系列浓度的GW003、吉粒芬、G-CSF突变体,在培养12d后计数粒-巨噬细胞系集落（CFU-GM）。结果表明,GW003具有提高正常恒河猴骨髓有核细胞体外形成CFU-GM的能力,效果明显优于相同摩尔浓度的吉粒芬 及G-CSF突变体;在-定的浓度范围内,GW003浓度与恒河猴骨髓细胞形成CFU-GM的数量呈明显的剂量效应关系（r=R2=0．965,P=0．003）;GW003能提高ALL患者骨髓细胞粒系集落体外形成能力,对化疗中患者的效果更为显著,可有效缓解化疗引起的骨髓抑制。结论：GW003可显著提高骨髓细胞体外形成粒细胞集落的能力,可有效缓解骨髓抑制。     

单中心191例健康供者应用G-CSF动员造血干细胞的影响因素分析

本研究旨在探讨粒细胞集落刺激因子（G-CSF）动员外周血造血干细胞的影响因素及对健康供者的影响。181例志愿健康供者应用G-CSF5-10μg/（kg·d）动员,10例应用G-CSF3．3-4．9μg/（kg·d）动员,12h1次,连续动员4-5d;采集、检测外周血中单个核细胞（MNC）数与CD34＋细胞数,并观察供者动员及采集过程中的不良反应。结果表明,与动员前相比,动员后（采集前）供者外周血白细胞数平均升高7倍（P〈0．01）;血小板数明显下降（P〈0．01）;血红蛋白含量无明显差异性。动员第4或5天采集效果无差异。男性供者采集的MNC、CD34＋细胞数高于女性（P〈0．01）,高体重供者采集的MNC、CD34＋数高于低体重供者,年龄对采集效果无明显影响。G-CSF剂量与采集效果无线性关系。供者不良反应轻微。结论：G-CSF可以有效动员外周血造血干细胞,供者无明显的不良反应。     

G-CSF的不同方案动员正常供者外周血干细胞的效果比较

为了研究粒细胞集落刺激因子(rhG-CSF)动员的最佳动员方案,对HLA完全相合的非清髓异基因外周造血干细胞移植的供者60例进行回顾性分析。结果显示:供者rhG-CSF10μg/(kg·d)的动员方案组所采集的单个核细胞及CD34+细胞数明显高于供者rhG-CSF5μg/(kg·d)的动员方案组(P<0.05)。供者rhG-CSF10μg/(kg·d)的动员方案在第4天或第5天采集时所获得的单个核细胞及CD34+细胞数无统计学差别。供者不同rhG-CSF动员剂量及采集时间所获得的CD3+、CD4+、CD8+细胞的百分比无统计学差别。结论:供者10μg/(kg·d)的动员效果明显优于供者5μg/(kg·d)的动员效果。供者10μg/(kg·d)的动员方案在第4天或第5天采集时效果无统计学差异,但第4天采集可缩短动员天数,降低费用,因此对供者采用10μg/(kg·d)动员方案时在第4天采集单个核细胞效果更好。     

Augmented mobilization and collection of CD34+ hematopoietic cells from normal human volunteers stimulated with granulocyte-colony-stimulating factor by single-dose administration of AMD3100, a CXCR4 antagonist

BACKGROUND: AMD3100, a selective antagonist of CXCR4, rapidly mobilizes CD34+ hematopoietic progenitor cells (HPCs) from marrow to peripheral blood with minimal side effects. STUDY DESIGN AND METHODS: To further investigate potential clinical utility of AMD3100 for CD34+ cell mobilization and collection, a Phase I study in normal volunteers was performed examining single-dose administration of AMD3100 alone and in combination with a standard 5-day granulocyte-colony-stimulating factor (G-CSF) regimen. RESULTS: AMD3100 (160 microg/kg x 1 on Day 5) significantly increased both G-CSF-stimulated (10 microg/kg/day) mobilization of CD34+ cells (3.8-fold) and leukapheresis yield of CD34+ cells. Moreover, collection of CD34+ cells was comparable between individuals mobilized by a single-dose regimen of AMD3100 (240 microg/kg) and individuals mobilized with a 5-day regimen of G-CSF. AMD3100-mobilized leukapheresis products contained significantly greater numbers of T and B cells compared to G-CSF-stimulated leukapheresis products. CONCLUSION: These findings indicate that AMD3100 can be used alone or as an adjunct to G-CSF to mobilize cells for HPC transplantation.     

AMD3100动员造血肝脏细胞作用的量效关系

目的 探讨AMD3100动员造血干祖细胞动员作用的量效关系.方法 40只实验小鼠分为A、B、C、D、E五组,A组皮下注射等体积的生理盐水;B、C、D、E组分别皮下注射AMD3100 1.25、2.5、5、10mg/kg.2h后尾静脉取血,分别检测外周血白细胞计数、KSL细胞数及KL细胞.结果 用药后B、C、D、E组白细胞KSL及KL细胞均比用药前升高(P＜0.05),随着用药剂量升高,白细胞、KSL细胞及KL细胞数逐渐升高,当剂量达到5 mg/kg时达到作用高峰.结论 AMD3100对造血干/祖细胞动员作用随着剂量增大而加强,有一定的剂量依从关系.     

Assessment of rapid remobilization intervals with G–CSF and SCF in murine and rhesus macaque models

BACKGROUND: Defining the optimum regimen and time for repeat peripheral blood progenitor cell mobilization would have important clinical applications. STUDY DESIGN AND METHODS: Remobilization with SCF and G-CSF at 2 weeks after an initial mobilization in mice and at 2 or 4 weeks after an initial mobilization in nonhuman primates was examined. In mice, competitive repopulation assays were used to measure long-term progenitor cell-repopulating activity. In monkeys, mobilization of hematopoietic progenitor CFUs was used as a surrogate marker for progenitor cell-repopulating ability. RESULTS: Efficacy of progenitor cell remobilization differed in the two animal species. In mice, peripheral blood progenitor cell-repopulating ability with repeat mobilization at 2 weeks was 70 percent of that with the initial mobilization. In monkeys, there was no significant difference in peripheral blood progenitor cell mobilization between the initial and the repeat mobilizations at 2 weeks. In mobilizations separated by 4 weeks, however, peripheral blood progenitor cell mobilization was higher than that with initial mobilizations. CONCLUSION: In animal models, mobilization of peripheral blood progenitor cells with remobilization after a 2-week interval is similar to or moderately decreased from that with the initial mobilization. Progenitor cell collection at this time point may be useful in certain clinical circumstances. A 4-week interval between remobilizations may be preferable. Clinical trials in humans would be useful to clarify these issues.     

Interleukine-8 acts as a strong peripheral blood granulocyte-recruiting agent rather than as a hematopoietic progenitor cell-mobilizing factor

Intravenous infusion of Interleukine-8 has been shown to lead to a rapid mobilization of hematopoietic cells in mice and rhesus monkeys. We report in this study that the IL-8-mediated mobilizing effect results in low levels of circulating CD34+ cells, whereas a rapid and strong recruitment of mature granulocytes occurs. This would be of great interest for harvesting large numbers of functional granulocytes to fight infection in immunodepressed patients. We performed a kinetic study of the mobilization in a nonhuman primate model (Papio ursinus), mobilized with a single or double infusion of IL-8 with a dose range of 30-50 microg/kg of body weight. Blood was sampled every 15 min after the IL-8 infusion, and IL-8 plasma levels, complete blood counts, differential WBCC, colony-forming unit assays, and CD34+ cell evaluation assays were performed. At the same time, leukapheresis was performed on the anesthetized animal to collect either hematopoietic stem and progenitor cells (HSPC) or peripheral blood granulocytes (PBG) according to different collection settings. IL-8 induced a rapid increase of PBG (7-12-fold the basal values). The HSPC leukapheresis concentrate showed poor ex vivo expansion abilities. IL-8-mobilized peripheral blood polymorphonuclear cells showed normal oxidative, chemotactic, phagocytic, and adherence abilities. We suggest that IL-8-induced neutrophilia could be used as an allogeneic source of granulocytes for transfusion in neutropenic patients or in granulocyte dysfunction.     

Peripheral blood progenitor cell collection after epirubicin, paclitaxel, and cisplatin combination chemotherapy using EPO-based cytokine regimens: a randomized comparison of G-CSF and sequential GM-/G-CSF

BACKGROUND: The peripheral blood progenitor cell (PBPC) mobilization capacity of EPO in association with either G-CSF or sequential GM-CSF/G-CSF was compared in a randomized fashion after epirubicin, paclitaxel, and cisplatin (ETP) chemotherapy. STUDY DESIGN AND METHODS: Forty patients with stage IIIB, IIIC, or IV ovarian carcinoma were enrolled in this randomized comparison of mobilizing capacity and myelopoietic effects of G-CSF + EPO and GM-/G-CSF + EPO following the first ETP chemotherapy treatment. After ETP chemotherapy (Day 1), 20 patients received G-CSF 5 microg per kg per day from Day 2 to Day 13 and 20 patients received GM-CSF 5 microg per kg per day from Day 2 to Day 6 followed by G-CSF 5 microg per kg per day from Day 7 to Day 13. EPO (150 IU per kg) was given every other day from Day 2 to Day 13 to all patients in both arms of the study. Apheresis (two blood volumes) was performed during hematologic recovery. RESULTS: The magnitude of CD34+ cell mobilization and the abrogation of patients' myelosuppression were comparable in both study arms; however, GM-/G-CSF + EPO patients had significantly higher CD34+ yields because of a higher CD34+ cell collection efficiency (57.5% for GM-/G-CSF + EPO and 46.3% for G-CSF + EPO patients; p = 0.0009). Identical doses of PBPCs mobilized by GM-/G-CSF + EPO and G-CSF + EPO drove comparable hematopoietic recovery after reinfusion in patients treated with identical high-dose chemotherapy. CONCLUSION: The sequential administration of GM-CSF and G-CSF in combination with EPO is feasible and improves the PBPC collection efficiency after platinum-based intensive polychemotherapy, associating high PBPC mobilization to high collection efficiency during apheresis.     

影响恶性肿瘤患者造血系统自体外周血造血干细胞数量和质量的因素分析

背景:造血系统恶性肿瘤的造血重建除与疾病本身、预处理方案、移植后支持治疗手段等相关外,自体外周血造血干细胞的动员、采集和冻存是影响其移植后造血系统顺利重建的关键因素。目的:观察造血系统恶性肿瘤患者自体外周血造血干细胞经动员、采集和冻存后,重新回输至造血系统的重建情况,并分析影响外周血造血干细胞数量和质量的因素。设计:以造血系统恶性肿瘤为对象的病例分析。单位:解放军广州军区广州总医院血液科,南方医科大学珠江医院血液科。对象:选取2000-02/2004-12解放军广州军区广州总医院血液科收治的18例造血系统恶性肿瘤住院患者,年龄16～56岁,其中急性髓性白血病2例,急性淋巴细胞白血病1例,淋巴瘤白血病2例,慢性粒细胞白血病2例,多发性骨髓瘤4例,非霍奇金淋巴瘤7例。粒细胞集落刺激因子(Granocyte,中外制药产品,批号N3G31)。方法:①全部病例均采用对肿瘤有效的联合化疗方案 粒细胞集落刺激因子进行动员。联合化疗方案:白血病患者第1～3天每隔12h给予阿糖胞苷2g/m2,第1～5天给予足叶乙甙200mg/m2或氟达拉宾50mg/m2。多发性骨髓瘤患者给予阿糖胞苷方案同上,第1～2天给予环磷酰胺1g/m2。淋巴瘤患者第1～2天给予环磷酰胺2g/m2。各类型患者化疗后白细胞降至1.0×109L-1以下时开始进行粒细胞集落刺激因子动员,5μg/(kg.d)皮下注射至采集结束。②当白细胞恢复至(4.0～10.0)×109L-1时开始采集外周血造血干细胞,单个核细胞计数≥4.0×108/kg或CD34 细胞≥2.0×106/kg时结束采集,经程序降温仪处理置入-196℃液氮中保存,37～40℃水浴解冻。③患者病灶部位行局部照射预处理,200cGy/次,5次/周,连续4周,总剂量40Gy。结束后48h回输外周血造血干细胞(55.3±28.7)mL,回输日距采集日平均为(56.5±22.3)d。全部患者于干细胞移植后第1天起皮下注射粒细胞集落刺激因子300μg/d,至中性粒细胞≥0.5×109L-1时停止。检测冻存前及解冻后自体外周血造血干细胞的锥虫蓝拒染率、单个核细胞计数、粒-单系祖细胞集落数及CD34 细胞百分率。主要观察指标:①自体外周血造血干细胞的采集情况。②冻存后自体外周血造血干细胞存活率及相关指标检测。③自体外周血造血干细胞移植后造血系统重建情况。结果:18例造血系统恶性肿瘤患者全部进入结果分析。①18例患者自体外周血造血干细胞平均采集时间为化疗后12.6d,采集次数为1.9次,采集第1天白细胞总数为(8.93±1.27)×109L-1,单个核细胞采集率为(138.33±28.61)%。②冻存后18例自体外周血造血干细胞标本锥虫蓝拒染率与冻存前基本相似[(96.26±1.33)%,(92.75±2.04)%,P>0.05]。解冻后单个核细胞、CD34 、粒-单系祖细胞回收率分别为(91.96±1.37)%,(85.94±0.64)%,(87.69±4.53)%。骨髓瘤患者的单个核细胞采集率、CD34 细胞百分率及粒-单系祖细胞集落数均明显低于白血病和淋巴瘤患者(t=2.524～3.268,P<0.05)。③移植后15d,15例患者中性粒细胞恢复至≥0.5×109L-1;移植后20d,血小板恢复至≥20×109L-1。化疗疗程>10次的5例患者粒-单系祖细胞生长不良,为(18.67～26.82)×105/kg,其中3例出现自体外周血造血干细胞移植后造血重建延迟。结论:①重组粒细胞集落刺激因子与大剂量化疗联合的动员方案可缩短外周血造血干细胞采集时间,提高单个核细胞采集率。②移植前化疗次数增多可影响自体外周血造血干细胞的数量和质量,导致造血重建延迟。     

重组人G-CSF对健康供者外周造血干／祖细胞动员和采集效果的影响因素分析

应用重组人粒系集落刺激因子（rhG—CSF）对健康供者进行动员并采集造血干细胞用于异基因外周血造血干细胞移植已在临床广泛应用，本研究通过对影响外周干细胞动员和采集效果的多因素分析，进一步探讨最佳动员方案及采集时机。采取回顾性方法分析了431例健康供者外周血干细胞动员采集效果，并进一步分析了供者一般特征、rhG—CSF动员天数、每日皮下注射次数、剂量与采集效果的关系。结果表明：rhG—CSF在动员中平均应用剂量为5．7μg／（kg·d），平均采集1．7次，收获单个核细胞数平均为9．57×10^8／kg，CD34^＋细胞平均为4．91×10^6／kg。绝大多数供者不良反应轻微。多因素分析结果显示，采集效率主要与供者体重指数，采集天数相关。rhG—CSF动员第5天采集的供者，其MNC数、CD34^＋细胞数及第一次单采成功率均优于其他时间采集的供者。同时，本组供者应用rhG—CSF剂量较小且剂量范围较窄，rhG—CSF剂量不如采集时间对采集物质量的影响明显。结论：小剂量应用rhG—CSF动员并于第5天开始采集是健康供者造血干细胞动员的较理想方案。     

Successful PBSC mobilization with high-dose G-CSF for patients failing a first round of mobilization.

PBSC are the preferred source of stem cells for autologous transplantation. However, regardless of the mobilization procedure used, 10%-20% of patients fail to collect an adequate number to ensure prompt engraftment. There is as yet no standard mobilization procedure for patients who fail a first mobilization attempt. Here, we describe a highly efficient strategy to obtain an adequate number of stem cells for patients who failed a first mobilization attempt. Seventy-four patients with various hematologic malignancies underwent initial mobilization with various regimens including hematopoietic growth factors with or without chemotherapy. In 72% of patients, > or =2 x 10(6) CD34+ stem cells/kg were collected in the initial mobilization attempt, and patients engrafted in a median of 10 days for neutrophils and 12 days for platelets. Eighteen patients failed to mobilize adequate numbers of stem cells, defined as the inability to collect 0.2 x 10(6) CD34+ stem cells/kg/day in the first 2-3 days. These patients had their apheresis halted. Patients were immediately given G-CSF (32 microg/kg/day) for 4 days as a second attempt at mobilization. Eighty-eight percent of these patients achieved the target of > or =2 x 10(6) CD34+ cells/kg, with a median duration of apheresis of 5 days (including the first and second mobilizations). The mean CD34+ cells/kg/day increased after administration of high-dose G-CSF from 0.16 after the first mobilization attempt to 0.61 (p = 0.0002) after the second mobilization. All patients engrafted in a median of 11 and 13 days for neutrophils and platelets, respectively. We conclude that patients whose apheresis yield is <0.4 x 10(6) CD34+ cells/kg after the first two apheresis collections can be successfully mobilized if high-dose G-CSF is administered immediately and continued until achieving > or =2 x 10(6) CD34+ stem cells/kg.