Efficacy Of CD34 Research Articles

Transplantation of CD34+ cells for myocardial ischemia.

CD34+ cells are multipotent hematopoietic stem cells also known as endothelial progenitor cells and are useful in regenerative medicine. Naturally, these cells are mobilized from the bone marrow into peripheral circulation in response to ischemic tissue injury. CD34+ cells are known for their high proliferative and differentiation capacities that play a crucial role in the repair process of myocardial damage. They have an important paracrine activity in secreting factors to stimulate vasculogenesis, reduce endothelial cells and cardiomyocytes apoptosis, remodel extracellular matrix and activate additional progenitor cells. Once they migrate to the target site, they enhance angiogenesis, neovascularization and tissue regeneration. Several trials have demonstrated the safety and efficacy of CD34+ cell therapy in different settings, such as peripheral limb ischemia, stroke and cardiovascular disease. Herein, we review the potential utility of CD34+ cell transplantation in acute myocardial infarction, refractory angina and ischemic heart failure.

Feasibility and efficacy of low-dose pegfilgrastim for CD34+ cell mobilization in lymphoma.

Pegfilgrastim has equivalent efficacy to daily granulocyte colony-stimulating factor (G-CSF) in enhancing neutrophil recovery after chemotherapy, but data on its use for peripheral blood stem cell (PBSC) mobilization are limited. We evaluated the safety and efficacy of CD34+ PBSC mobilization by low-dose (3.6 mg) pegfilgrastim after chemotherapy in patients with malignant lymphoma. Twenty patients with malignant lymphoma were enrolled in this study. Cytotoxic chemotherapy was started on day 1, and 3.6 mg of pegfilgrastim was subcutaneously administered on day 7. CD34+ cells were counted in the peripheral blood daily from days 11 to 14 using a flow cytometric analysis. In 19 of the 20 patients (95%), the CD34+ cell counts in the peripheral blood exceeded 10 × 106/L, with a mean value of 20.3 on day 11, 38.0 on day 12, 40.3 on day 13, and 40.1 on day 14. Older age was associated with lower maximum CD34+ cell mobilization. The most frequent adverse events associated with pegfilgrastim were back pain, nausea, appetite loss, and lactate dehydrogenase elevation. Our data indicated that a single dose of 3.6 mg pegfilgrastim on day 7 after chemotherapy safely and effectively mobilized CD34+ cells.

Optimal timing of apheresis for the efficient mobilization of peripheral blood progenitor cells recruited by high-dose granulocyte colony-stimulating factor in healthy donors

Predictors of peripheral blood stem cell (PBSC) yield can potentially improve the comfort, safety, and efficacy of CD34+ cell collection from donors treated with recombinant human granulocyte colony-stimulating factor (G-CSF). We investigated 181 apheresis procedures on 109 healthy allogeneic donors to identify factors correlating with efficient PBSC collection. Apheresis started on Day 4 or 5 and continued up to Day 6 of G-CSF administration. CD34+ cell yields on Days 4 and 5 were comparable, and significantly higher than on Day 6. This suggests that starting apheresis on Day 4 rather than Day 5 may be preferable, to reduce G-CSF exposure and optimize yield, even if multi-day collection is required. More CD34+ cells were collected from male and cytomegalovirus (CMV)-seronegative donors than from female and CMV-seropositive donors, respectively. The yields of CD34+ cells were similarly high in both male and female donors aged 20–29 years; yields decreased in female donors in their thirties, and were comparably low in both male and female donors in their forties and thereafter. These findings should guide decision-making about when to begin apheresis, and encourage careful consideration of donor factors such as gender, age, and CMV serostatus when collecting PBSCs.

Promise of autologous CD34+ stem/progenitor cell therapy for treatment of cardiovascular disease.

CD34+ cells are haematopoietic stem cells used therapeutically in patients undergoing radiation or chemotherapy due to their regenerative potential and ability to restore the haematopoietic system. In animal models, CD34+ cells have been associated with therapeutic angiogenesis in response to ischaemia. Several trials have shown the potential safety and efficacy of CD34+ cell delivery in various cardiovascular diseases. Moreover, Phase III trials have now begun to explore the potential role of CD34+ cells in treatment of both myocardial and peripheral ischaemia. CD34+ cells have been shown to be safe and well-tolerated in the acute myocardial infarction (AMI), heart failure, and angina models. Several studies have suggested potential benefit of CD34+ cell therapy in patients with coronary microvascular disease as well. In this review, we will discuss the therapeutic potential of CD34+ cells, and describe the pertinent trials that have used autologous CD34+ cells in no-options refractory angina, AMI, and heart failure. Lastly, we will review the potential utility of autologous CD34+ cells in coronary endothelial and microvascular dysfunction.

Human primary CD34+ cells transplantation for critical limb ischemia.

The goal of this study was to characterize the properties of human CD34+ cells in culture and investigate the feasibility and efficacy of CD34+ transplantation in a mouse model of limb ischemia and in patients with no-option critical limb ischemia. Human CD34+ cells isolated from peripheral blood and grown in culture for up to four passages stained positively for the surface markers CD34 and CD133 and showed high viability after cryopreservation and recovery. Seven days after surgery to induce limb ischemia, ischemic muscles of nude mice were injected with CD34+ cells. Two weeks later, mice were scored for extent of ischemic injury, and muscle tissue was collected for immunohistochemical analysis of vascular endothelial cells and RT-PCR analysis of cytokine expression. Injury scores of CD34+ -treated, but not control, mice were significantly different before and after transplantation. Vascular density and expression of VEGF and bFGF mRNAs were also significantly increased in the treated mice. Patients with severe lower extremity arterial ischemia were injected with their own CD34+ cells in the affected calf, foot, or toe. Significant improvements were observed in peak pain-free walking time, ankle-brachial index, and transcutaneous partial oxygen pressure. These findings demonstrate that growth of human CD34+ cells in vitro and cryopreservations are feasible. Such cells may provide a renewable source of stem cells for transplantation, which appears to be a feasible, safe, and effective treatment for patients with critical limb ischemia.

Correlation between Therapeutic Efficacy of CD34+ Cell Treatment and Directed In Vivo Angiogenesis in Patients with End-Stage Diffuse Coronary Artery Disease.

Background This study was aimed at testing the association between the therapeutic efficacy of CD34+ cell treatment in patients with end-stage diffuse coronary artery disease as reflected in angiographic grading and results of directed in vivo angiogenesis assay (DIVAA) on their isolated peripheral blood mononuclear cell- (PBMC-) derived endothelial progenitor cells (EPCs). Methods Angiographic grades (0: <5%; 1: 5–35%; 2: 35–75%; 3: >75%) which presented the improvement of vessel density pre- and post-CD34+ treatment were given to 30 patients with end-stage diffuse coronary artery disease having received CD34+ cell treatment. The patients were categorized into low-score group (angiographic grade 0 or 1, n = 12) and high-score group (angiographic grade 2 or 3, n = 18). The percentages of circulating EPCs with KDR+/CD34+/CD45−, CD133+/CD34+/CD45−, and CD34+ were determined in each patient using flow cytometry. PBMC-derived EPCs from all patients were subjected to DIVAA through a 14-day implantation in nude mice. The DIVAA ratio (i.e., mean fluorescent units in angioreactors with EPCs/mean fluorescent units in angioreactors without EPCs) was obtained for each animal with implanted EPCs from each patient. Results and Conclusions The number of EPCs showed no significant difference among the two groups. The DIVAA ratio in the high-score group was significantly higher than that in the low-score group (p = 0.0178). Logistic regression revealed a significant association between the DIVAA ratio and angiographic grading (OR 3.12, 95% CI: 1.14–8.55, p = 0.027). The area under the ROC curve (AUC) was 0.8519 (p = 0.0013). We proposed that DIVAA may be a reliable tool for assessing coronary vascularization after CD34+ cell treatment.

Study on the efficacy of CD34+ cells combined with sarpogrelate hydrochlotride tablets for the reconstruction of the blood supply of thromboangiitis obliterans

Objective To investigate the effect of autologous peripheral blood stem cell transplantation combined with CD34+ cells and oral sarpogrelate hydrochloride for the treatment of vascular reconstruction and blood supply on the thromboangiitis obliterans. Methods Thromboangiitis obliterans (TAO) of 262 patients with 262 lower limbs were divided into stem cells CD34+ cells transplantation combined with sarpogrelate hydrochloride group (group A) with 100 lower limbs, CD34+ stem cell transplantation group (group B) with 91 lower limbs, and sarpogrelate hydrochloride oral group ( group C) with 71 lower limbs. The degree of lower limb local blood flow variability were calculated at the three levels of skin, blood vessels and blood by preoperative and postoperative use of multi-function monitoring instrument, Doppler detector, transcutaneous oxygen pressure monitor, and digital subtraction angiography (DSA), respectively. Results ⑴ The degree of shank, foot cyanosis, cool skin, and pain was relieved significantly in groups A and B than in group C for 1 month after the treatment (P<0.05). ⑵ Intermittent claudication distance, the skin temperature of the lower leg and foot to patients in the groups A and B than in group C, with a significant difference (F=7.01, F=7.04, P<0.05) for 3 months after the treatment. ⑶ Among the patients with amputation, 10 cases were in group A, 16 cases in group B, and 31 cases in group C for 6 months after the treatment. ⑷ Transcutaneous oxygen pressure was increased from (30.43±4.31)mmHg to (37.21±9.01)mmHg (F=5.69, P<0.05), ankle brachial index from (0.32±0.23) to (0.91 ± 0.16) (F=6.71, P<0.05), the volume of blood flow index from the photoelectric (0.22±0.04) to (0.83±0.13 (F=5.69, P<0.05), oxygen saturation from (42.41±9.61)% to (79.61±20.34)% (F=5.74, P<0.05), and DSA score (0.23±0.03) increased to (1.35±0.23) (F=7.14, P<0.05), which was significantly higher than group B and group C (F=7.01, F=7.04, F=7.12, F=7.08, F=7.15, P<0.05) for one year after treatment. Conclusions Treatment of peripheral blood stem cells CD34+ cell transplantation combined with oral sarpogrelate hydrochloride can significantly improve the vascular regeneration and its blood supply in TAO lower extremity limb. Key words: Peripheral blood stem cell transplantation; Antigens, CD34/AD; Platelet aggregation inhibitors/AD; Thromboangiitis obliterans/TH; Blood circulation

Safety and Efficacy of CD34+ Stem Cell Mobilization by Granulocyte Colony Stimulating Factor in Patients with Advanced Cirrhosis

Safety and Efficacy of CD34+ Stem Cell Mobilization by Granulocyte Colony Stimulating Factor in Patients with Advanced Cirrhosis

Rapid and Prolonged Mobilization of Human CD34+ Hematopoietic Stem Cells Following Intravenous (IV) Administration of Plerixafor

AbstractAbstract 2261 Background:Plerixafor (AMD3100) is a CXCR4 antagonist that was approved by the FDA for use in combination with G-CSF to mobilize hematopoietic stem and progenitor cells (HSPCs) in patients with non-Hodgkin's lymphoma and multiple myeloma. We have previously reported the use of plerixafor alone to mobilize HSPCs for HLA-matched allogeneic transplantation (Blood. 2008;112:990). In this trial, sibling donors were treated with plerixafor at a dose of 0.24 mg/kg by subcutaneous (SC) injection, followed 4 hours later by leukapheresis. To date, 15 of 45 donors (33%) required a second day of leukapheresis to collect the minimum cell dose of ≥ 2.0 × 106 CD34+ cells/kg actual recipient body weight that are required to proceed to transplantation. Based on preliminary data suggesting higher (2-fold) and earlier (1 hr vs. 3 hr) progenitor mobilization in mice after intravenous (IV) dosing of plerixafor, we amended our trial to test the safety and efficacy of IV plerixafor. Methods:In our Phase I trial, 21 healthy donors were initially mobilized with increasing doses of IV plerixafor (0.08, 0.16, 0.24, 0.32, 0.40 or 0.48 mg/kg). After 4 days of drug clearance, the same donors were then mobilized with a single SC dose of 0.24 mg/kg plerixafor followed 4 hours later by leukapheresis. In our Phase II study, 28 sibling donors were treated with plerixafor at a dose of 0.32 mg/kg by IV injection, followed 4 hours later by leukapheresis. Successful mobilization was defined as a minimum leukapheresis yield of ≥ 2.0 × 106/kg CD34+ cell/kg actual recipient body weight. Results:Peak CD34+ cells/mm3 were observed 4 hours after IV dosing (vs. 6–9 hours after SC dosing) and donors given 0.24 mg/kg IV plerixafor, had significantly higher peak levels of CD34+ cells/mm3 compared to the same donors who received 0.24 mg/kg SC plerixafor. There was a clear dose-response relationship of IV plerixafor on mobilization of CD34+ HSPCs, with the 0.32 mg/kg dose yielding a maximum increase in circulating CD34+ cells of 27 CD34+ cells/mm3 at 4 hours after injection, representing a median eight-fold increase from baseline. Interestingly, the median CD34+ cells/mm3 in donors receiving 0.40 mg/kg (N=3) and 0.48 mg/kg (N=3) was 17 and 24 CD34+ cells/mm3, respectively, not significantly better than the 320 mcg/kg dose at the four hour time-point. We also noted that IV dosing (especially doses >0.24 mg/kg) resulted in prolonged mobilization of CD34+ cells such that levels approached 20 CD34+ cells/mm3 at 24 hours after IV dosing. Pharmacokinetic studies demonstrated that the Cmax of plerixafor following the 0.32 mg/kg IV dose remained below 1.0 μg/mL whereas the 0.40 and 0.48 mg/kg doses resulted in Cmax levels of 1.8–2.2 μg/mL. A total of 28 HLA-identical sibling donor/recipient pairs have been enrolled in the Phase II trial, with all donors mobilized using IV plerixafor at a dose 0.32 mg/kg. At 4 hours after IV plerixafor, the CD34+ cell count rose to a median of 16 CD34+ cells/mm3 (range, 4–46), representing a 6.5-fold increase. The efficacy of CD34+ cell collection following 0.32 mg/kg IV plerixafor was not evaluable in five donors due to incomplete apheresis collections or the extremely large size of one recipient (recipient >200 kg). Six of the remaining 23 donors (26%) did not achieve the minimum cell dose of 2 × 106 CD34+ cells/kg in a single 20 L leukapheresis procedure. This mobilization failure rate of 26% with 0.32 mg/kg IV plerixafor is similar to the failure rate of 33% we observed following administration of 0.24 mg/kg SC plerixafor to healthy donors. Four of the six patients who failed to collect ≥ 2.0 × 106 CD34+ cells/kg after the first mobilization and apheresis procedure reached goal following a second mobilization and collection procedure. No adverse events or acute grade 3 or 4 toxicities have been observed in any of the donors given IV plerixafor doses up to 0.48 mg/kg. We have transplanted 24 of the 28 patients entered in the phase II trial. All but one patient engrafted neutrophils and platelets promptly and only 2 of the 24 (8.3%) transplant recipients have developed clinical evidence of acute GVHD (minimum follow-up of 45 days); 1 had grade II and the other grade III. Summary:IV plerixafor increases the magnitude and duration of CD34+ mobilization compared to SC plerixafor in healthy donors. These observations suggest that IV plerixafor may be a more effective mobilization agent with a low side effect profile for allogeneic transplantation. Disclosures:Rettig: Genzyme Corp.: Consultancy, Honoraria. DiPersio: Genzyme: Honoraria.

Role of substance P (SP) and calcitonin gene-related peptide (CGRP) in gibbon-ape-leukemia virus (GALV) transduction of CD34+ cells

Optimization of transduction condition is an important goal to improve gene transduction. Therefore, we aimed to assess the effect of SP and/or CGRP as novel growth/transducing factors on the efficacy of CD34(+) transduction. CD34(+) cells were transduced with Gibbon-Ape-Leukemia virus (GALV), containing Neomycin gene. CD34(+) cells were transduced with GALV presence of SP and/or CGRP. Real Time PCR and colony formation assay (CFU-C) was performed. Viral vectors titration on Hela cells indicated transduction efficiency of 1×10(6)CFU/ml. Real Time PCR of Neo and CFU-C showed stimulatory role of SP on gene transfer 5.9% and 14.84% compared to 3.6% and 12.58% in control group, while opposite role observed for CGRP 0.89% and 7.86%. Both SP and CGRP showed no significant effect in these assays. This study showed including of SP in growth factor cocktail is beneficial for CD34(+) transduction, which could be applied to genetic modification procedures.

The clinical significance of tumor cells in bone marrow or apheresis product and the efficacy of CD34+ selection and high‐dose chemotherapy in patients with Stage III breast cancer

The purpose of this study is to determine the presence of disseminated tumor cells in bone marrow or apheresis product, and also to evaluate the clinical significance of contaminated products and the efficacy of CD34(+) selection and high-dose chemotherapy in patients with Stage III breast cancer. Fifty-five patients were enrolled in this prospective cohort study. Whereas CD34(+) positive selection was not carried out in the first group (unselected group, n:31), CD34(+) positive selection was performed in the second group (CD34 selected group, n:24). Tumor cells were detected with anticytokeratin monoclonal antibody in the bone marrow, apheresis product and positive fraction. Tumor cells were found in six (19.3%) patients in unselected group and four patients (16.6%) in CD34 selected group (P = 0.76). The percentages of distant metastases were found higher in unselected group (51.6% vs. 25%, P < 0.01). Although there were no differences between the two groups for disease free survival (DFS; 44% vs. 74%, P = 0.24) or overall survival (54% vs. 68%, P = 0.84), DFS was significantly lower in patients with tumor cells than in patients without tumor cells (21% vs. 62%, P = 0.02). In conclusion, the presence of tumor cells in bone marrow or apheresis product decreases DFS in patients with Stage III breast cancer who underwent high-dose chemotherapy. CD34(+) selection does not change survivals, but it may decrease the distant metastases.

Relapse risk after autologous transplantation in patients with newly diagnosed myeloma is not related with infused tumor cell load and the outcome is not improved by CD34+ cell selection: long term follow-up of an EBMT phase III randomized study

This European Group for Blood and Marrow Transplantation (EBMT) multicentre randomized phase III study was designed to assess the safety and efficacy of CD34+ selection in newly diagnosed myeloma patients undergoing autologous transplantation. One hundred and eleven patients responsive to initial chemotherapy were randomized to receive CD34+ selected (arm A) or unselected PBPC (arm B) after conditioning with high-dose melphalan and TBI. ASO-PCR was used to assess purging efficacy and reinfused tumor load. Tumor load could be assessed in 59 patients. CD34+ selection gave a median tumor cell depletion of 2.2 logs (0.77-5.96). No tumor cells were detected in products infused in 17/26 (A) and 5/33 (B) patients. The five year overall survival (OS), event free survival (EFS) and relapse rate (RR) were 51%, 20% and 80% in arm A and 45%, 18% and 80% in arm B respectively with no significant difference between the two groups. Thirteen patients in arm A and 2 in arm B experienced episodes of serious early infection (p=0.02). There were 3 early transplant related deaths in A but none in B. Despite significant tumor cell reduction, CD34+ selection does not reduce RR and increases the risk of severe post-transplant infections. There was also no difference in RR between patients in either arm who received grafts with detectable tumor cells and those receiving grafts with no detectable tumor cells, suggesting that reinfused tumor cells may not be the main cause of relapse after autologous transplant in myeloma.

Efficacy of CD34 + Stem Cell Dose in Patients Undergoing Allogeneic Peripheral Blood Stem Cell Transplantation after Total Body Irradiation

We estimated the effect of CD34 + stem cell dose during peripheral blood stem cell transplantation (PBSCT) in predicting mortality after total body irradiation (TBI). Between 1997 and 2004, 146 consecutive patients with hematologic malignancies received fractionated TBI (12-13.6 Gy) in 8 fractions over 4 days before undergoing PBSCT; 61 patients received TBI with reduced radiation dose to the lung (6-9 Gy). The number of CD34 + cells transplanted was recorded for all patients. A cubic spline representation for CD34 + dose within a Cox proportional hazards model was used to model the relationship between the CD34 + dose and mortality. Median follow-up was 44 months (range, 12–90 months). The CD34 + cell dose ranged from 2.45 to 15.90 × 10 6 cells/kg (median, 5.15 × 10 6 cells/kg). Risk of mortality decreased with CD34 + doses between 4–8 × 10 6 cells/kg and then began to increase. For all patients, CD34 + doses of 5.1–12.9 × 10 6/kg resulted in at least a doubling of median survival associated with the lowest CD34 + value. In patients treated with lung dose reduction, a similar range of CD34 + dose (4.3–10.2 × 10 6 cells/kg) produced at least a 5-fold improvement from the survival associated with the lowest CD34 + dose; however, the relationship between CD34 + dose and mortality was not statistically different when analyzed by lung dose reduction. A method for assessing risk of mortality by CD34 + dose as a continuous variable is presented. Risk of mortality decreased with CD34 + doses between 4-8 × 10 6 cells/kg and then began to increase.

CD34+-selected stem cell boost for delayed or insufficient engraftment after allogeneic stem cell transplantation

Poor graft function without rejection may occur after stem cell transplantation (SCT). CD34(+) stem cell boost (SCB) can restore marrow function but may induce or exacerbate GvHD. We therefore investigated the feasibility and efficacy of CD34(+)-selected SCB in some patients with poor graft function. We present the results for eight patients (median age 46 years) transplanted initially for myelofibrosis, acute leukemia, myeloma and NHL. Six patients had received HLA-matched and two mismatched grafts (PB, BM; n=5, 3). After a median of 128 days post-transplant, the median leukocyte and platelet counts were, respectively, 2.05/nL and 18/nL. None had achieved platelet counts >50/nL even though donor chimerism was >95% in seven recipients. Positive selection of CD34(+) stem cells was performed on a CliniMACS device, observing GMP and achieving a median of 98.5% purity. The patients received a median of 1.7 x 10(6)/kg CD34(+) cells and 2.5 x 10(3)/kg CD3(+) T lymphocytes. Hemograms at days +30, +60 and +90, respectively, showed steadily increasing median leukocyte (2.55, 3.15 and 4.20/nL) and platelet (29, 39 and 95/nL) counts. After a median follow-up of 144 days, five patients remained alive. No patient had developed acute or chronic GvHD. One patient died of leukemic relapse and two others of systemic mycosis. These preliminary results point to the possibility of safely improving graft function using CD34(+) positively selected stem cells without necessarily increasing the incidence of GvHD in patients with poor graft function post-SCT. Experience with more patients and longer follow-up should clarify the optimal role for this procedure.

CD34+ cells purified autologous peripheral blood stem cell transplantation for the treatment of refractory autoimmune diseases

The aim of this study was to evaluate the safety and efficacy of CD34+ cells in autologous peripheral blood stem cell transplantation (PBSCT) for the treatment of refractory autoimmune diseases (AD). Methods: Six cases of systemic sclerosis (SSc) with interstitial pneumonia (IP), one case of amyopathic dermatomyositis (ADM) with IP, and one case of Wegener’s granulomatosis with exophthalmous. PBSCs were mobilized with CY 4 g/m2+ G-CSF, and CD34+ cells were purified with CliniMACS. Pretransplantation conditioning consisted of CY 200 mg/kg.

Feasibility of a PB CD34+ cell transplantation procedure using standard leukapheresis products in very small children

To evaluate the feasibility and efficacy of CD34+ cell immunoselection from routine peripheral blood stem cell (PBSC) harvests in very small children a prospective study was performed in 15 children with advanced neuroblastoma weighing 20 kg or less. Products of two consecutive leukaphereses carried out on a COBE Spectra separator after G-CSF alone mobilization were pooled for immunoselection on Ceprate column. The median number of CD34+ cells and total CFU-GM collected were respectively 5.9 x 10(6)/kg (range 2.3-23.4) and 126.9 x 10(4)/kg (range 52.9-559.9). After separation the median number of CD34+ cells in the adsorbed fraction was 2.6 x 10(6)/kg (range 1-9.8) with a median purity of 54% (range 21-82) and a median of 95.7-fold (range 35-250) enrichment. Thirteen patients underwent autografts with CD34+ PBSCs after a busulfan 600 mg/m2 + melphalan 180 mg/m2 preparative regimen. The median number of days to achieve an absolute granulocyte count of 0.5 x 10(9)/l and a platelet count of 20 x 10(9)/l were respectively, 12 (range 10-24) and 35 (range 25-43). The median number of platelet transfusions was nine (range 2-15). We conclude that safe and effective immunoselection and transplantation of CD34+ PBSC can be accomplished in children with low body mass.