Retroviral transduction efficiency of G-CSF+SCF–mobilized peripheral blood CD34+ cells is superior to G-CSF or G-CSF+Flt3-L–mobilized cells in nonhuman primates

Blood ◽  
2003 ◽  
Vol 101 (6) ◽  
pp. 2199-2205 ◽  
Author(s):  
Peiman Hematti ◽  
Stephanie E. Sellers ◽  
Brian A. Agricola ◽  
Mark E. Metzger ◽  
Robert E. Donahue ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Peripheral Blood ◽  
Nonhuman Primates ◽  
Transduction Efficiency ◽  
Target Cells ◽  
Hematopoietic Stem ◽  
Retroviral Transduction ◽  
Peripheral Blood Cd34 ◽  
Cd34 Cells ◽  
Clinical Gene Therapy

Gene transfer experiments in nonhuman primates have been shown to be predictive of success in human clinical gene therapy trials. In most nonhuman primate studies, hematopoietic stem cells (HSCs) collected from the peripheral blood or bone marrow after administration of granulocyte colony-stimulating factor (G-CSF) + stem cell factor (SCF) have been used as targets, but this cytokine combination is not generally available for clinical use, and the optimum target cell population has not been systematically studied. In our current study we tested the retroviral transduction efficiency of rhesus macaque peripheral blood CD34+ cells collected after administration of different cytokine mobilization regimens, directly comparing G-CSF+SCF versus G-CSF alone or G-CSF+Flt3-L in competitive repopulation assays. Vector supernatant was added daily for 96 hours in the presence of stimulatory cytokines. The transduction efficiency of HSCs as assessed by in vitro colony-forming assays was equivalent in all 5 animals tested, but the in vivo levels of mononuclear cell and granulocyte marking was higher at all time points derived from target CD34+ cells collected after G-CSF+SCF mobilization compared with target cells collected after G-CSF (n = 3) or G-CSF+Flt3-L (n = 2) mobilization. In 3 of the animals long-term marking levels of 5% to 25% were achieved, but originating only from the G-CSF+SCF–mobilized target cells. Transduction efficiency of HSCs collected by different mobilization regimens can vary significantly and is superior with G-CSF+SCF administration. The difference in transduction efficiency of HSCs collected from different sources should be considered whenever planning clinical gene therapy trials and should preferably be tested directly in comparative studies.

Ex Vivo Expansion of Retrovirally-Transduced Primate CD34+ Cells Results in Preferential Engraftment and Persistence of Clones with MDS1/EVI1 Insertion Sites.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 203-203
Author(s):  
Theo Gomes ◽  
Stephanie Sellers ◽  
Robert E. Donahue ◽  
Rima Adler ◽  
Andre La Rochelle ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Insertional Mutagenesis ◽  
Ex Vivo ◽  
Safety Issue ◽  
Retroviral Vectors ◽  
Ex Vivo Expansion ◽  
Target Cells ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Clinical Gene Therapy

Abstract There is increasing evidence that insertional activation of proto-oncogenes by retroviral vectors is a significant safety issue that must be addressed before clinical gene therapy, particularly targeting hematopoietic stem and progenitor cells, can be further developed. The risk of insertional mutagenesis for replication-incompetent retroviral vectors has been assumed to be low until the occurence of T cell leukemias in children treated with HSC-directed gene therapy for X-SCID, and recent evidence that retroviral integration is more common in the promoter region of transcriptionally-active genes. The occurence of “common integration sites” in a particular gene also suggests a non-random insertion pattern, and/or immortalization or other change in the behavior of a clone harboring an insertion in these particular genes. We have previously reported a highly non-random occurence of 14 unique vector integrations in the first two introns of the MDS1/EVI1 proto-oncogene out of a total of 702 identified from myeloid cells of 9 rhesus macaques at least 6 months post-transplantion of retrovirally-transduced CD34+ cells.(Calmels et al, 2005). This same gene locus was found frequently activated by insertions in murine bone marrow cells immortalized in long-term in vitro culture after transduction with retroviral vectors.(Du et al Blood, 2005) To begin to investigate the factors contributing to this worrisome finding, particularly given the very recent report of a marked over-representation of MDS1/EVI1 insertions in a human clinical gene therapy trial for chronic granulomatous disease, we asked whether continued ex vivo expansion of transduced CD34+ cells prior to transplantation would further select for clones with insertions in MDS1/EVI1 or other proto-oncogenes. Rhesus CD34+ cells were transduced with the G1Na standard retroviral vector, identical to that used in the prior studies, using our standard 96 hour transduction protocol in the presence of Retronectin and SCF, FLT3L and thrombopoietin. At the end of transduction, all cells were continued in culture for an additional 7 days under the same culture conditions, and then reinfused into the donor animal following 1200 rads TBI. At 1 month post-transplant there were no CIS and no MDS1/EVI1 insertions identified. However, at 6 months post-transplantation 5 out of 27 (19%) of the unique insertions identified in granulocytes were within the first two introns of MDS1/EVI1, very significantly higher than the 2% of MDS1/EVI1 insertions (14 of 702) identified in animals that were transplanted with cells not subjected to additional ex vivo expansion.(p<.0001) One MDS1/EVI1 clone constituted 14% of overall sequences identified, and the 5 clones constituted 37% of total sequences identified. This strongly suggests that the over-representation of this locus in engrafting cells is due to a potent immortalizing signal provided by activation of the MDS1/EVI1 gene products by the stonger retroviral promoter/enhancer, and that the need for extended ex vivo culture of target cells may select for insertion events activating this locus. It also suggests that strategies involving prolonged ex vivo expansion or selection of transduced cells could increase the risk of gene therapy utilizing integrating vectors targeting primitive hematopoietic cells.

scholarly journals Fully Closed, Large-Scale, and Clinical Grade Cell Sorting of Hematopoietic Stem Cell (HSC)-Enriched CD90+ Cells for Transplantation and Gene Therapy

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3246-3246
Author(s):  
Stefan Radtke ◽  
Margaret Cui ◽  
Anai M Perez ◽  
Yan-Yi Chan ◽  
Stefanie Schmuck ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Bone Marrow ◽  
Stem Cell ◽  
Transduction Efficiency ◽  
Target Cells ◽  
Gene Modification ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Cell Fractions

Introduction: Hematopoietic stem cell (HSC) gene therapy/editing is a viable treatment option for various hematological diseases and disorders including hemoglobinopathies and HIV/AIDS. Most if not all currently available approaches target CD34-enriched cell fractions, a heterogeneous mix of mostly committed progenitor cells and only very few true HSCs with long-term multilineage engraftment potential. As a consequence, gene therapy/editing approaches are currently limited in their HSC targeting efficiency, very expensive consuming huge quantities of modifying reagents, and can lead to unwanted side-effects in non-target cells. We recently described a novel HSC-enriched CD34 subset (CD90+CD45RA-) that is exclusively responsible for rapid recovery onset, robust long-term multilineage engraftment, as well as entire reconstitution of the bone marrow stem cell compartment in the nonhuman primate (NHP) stem cell transplantation and gene therapy model (Radtke et al. 2017, STM). Most importantly, we demonstrate that this CD34 subset reduces the number of target cells, modifying reagents and costs by more than 10-fold without compromising the long-term efficiency of gene-modification in the NHP (Humbert and Radtke et al. 2019, STM). Here, we aimed to develop a clinical protocol to reliably purify and efficiently gene-modify human HSC-enriched CD90+ cell fractions. Methods: Large-scale enrichment of CD34+ cells from GCSF-mobilized leukapheresis products was initially performed on the Miltenyi CliniMACS Prodigy according to previously established protocols (Adair et al. 2017, Nat. Comm.). Yield, purity, quality, and feasibility of CD90 sorting was then comprehensively tested on two different commercially available cell sorting systems comparing the jet-in-air sorter FX500 from Sony and the cartridge-based closed-system sorter MACSQuant Tyto from Miltenyi Biotech with our clinically approved gold-standard CD34-mediated gene therapy approach. Sorted CD90+ and bulk CD34+ cells were transduced with a clinical-grade lentivirus encoding for GFP and the multilineage differentiation as well as engraftment potential tested using in vitro assays and the NSG mouse xenograft model, respectively. Results: Flow-cytometric sort-purification of CD90+ cells was similarly efficient in purity and yield using either the FX500 or Tyto (Figure A,B). Both approaches reliably reduced the overall target cell count by 10 to 15-fold without impacting the cells viability and in vitro colony-forming cell potential. Unexpectedly, the transduction efficiency of sort-purified CD90+ cells was significantly improved compared to bulk-transduced CD34+ cells and especially the CD34+CD90+ subset (Figure C). All cell fractions demonstrated robust mouse xenograft potential (Figure D). Most importantly, significantly higher levels of GFP+ expression in the peripheral blood, bone marrow, spleen and thymus were observed after transplantation of gene-modified CD90+ compared to bulk CD34+ cells in NSG mice (Figure E). Conclusion: Here, we show that sort-purification of our HSC-enriched CD34+CD90+ cell subset is technically feasible and highly reproducible in two different systems. Purification of human CD90+ cell fractions significantly increased the gene-modification efficiency of primitive human HSCs with multilineage mouse engraftment potential. These findings should have important implications for currently available as well as future HSC gene therapy and gene editing protocols. Isolation of an HSC-enriched phenotype will allow more targeted gene modification and thus likely reduce unwanted off target effects. Our approach further reduced the overall costs for gene modifying reagents, can be combined with a closed transduction system, increase the portability and ultimately make HSC gene therapy GMP-facility independent and affordable. Finally, this stem cell selection strategy may also allow efficient and effective depletion of donor T cells in the setting of allogeneic stem cell or organ transplantation. Figure: A) Purity and B) yield of CD90+ cells after sort-purification. C) Transduction efficiency of bulk-transduced CD34+CD90+ cells and sort-purified CD90+ cells. Frequency of D) human chimerism and E) GFP+ human CD45+ cells in the peripheral blood (PB), bone marrow, spleen and thymus after transplantation of gene-modified bulk CD34+ or sort-purified CD90+ cells. Figure Disclosures Kiem: CSL Behring: Consultancy; Rocket Pharma: Consultancy, Equity Ownership; Homology Medicines: Consultancy, Equity Ownership; Magenta Therapeutics: Consultancy.

Initiation of a Pre-Clinical Gene Therapy Study in Non-Human Primates Using Lentivectors Targeting Hematopoietic Cells for Correction of Fabry Disease.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5542-5542 ◽  
Author(s):  
Jagdeep S. Walia ◽  
Makoto Yoshimitsu ◽  
Josh D. Silvertown ◽  
Armando Poeppl ◽  
Vanessa I. Rasaiah ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Fabry Disease ◽  
Peripheral Blood ◽  
Rhesus Macaques ◽  
Marker Gene ◽  
Safety Information ◽  
Hematopoietic Cells ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Clinical Gene Therapy

Abstract Fabry disease is a lysosomal storage disorder (LSD) due to low or absent levels of α-galactosidase A (α-gal A). This results in accumulation of substrate with terminal galactosyl residues such as globotriaosylceramide (Gb3) in lysosomes causing pathology in different organs. Previously, we have demonstrated correction of the deficiency in Fabry mice in numerous gene therapy studies targeting hematopoietic cells. Here we have initiated a pre-clinical gene therapy study in non-human primates (NHPs) targeting Fabry disease. Three rhesus macaques are housed in our animal facility and implantation of telemetric devices and vascular access ports have occurred. We have mobilized hematopoietic stem/progenitor cells from all three animals independently by treatment for 5 days with 10 μg/kg/day of recombinant human granulocyte colony stimulating factor (rhuG-CSF) and 200 μg/kg/day recombinant human stem cell factor (rhuSCF). On the 5th day of mobilization, all animals underwent leukapheresis. To be more clinically relevant, we are using a protocol with an unmodified, commercially available apheresis machine for the rhesus macaques, which can be used for humans of an equivalent weight. From each successful apheresis, we collected approximately 1 x109/kg mobilized peripheral blood mononuclear cells (MoPBMNCs). After collection of MoPBMNCs, we isolated CD34+ cells using an anti-human CD34 antibody (clone 12.8) with a recovery of approximately 15–20 x 106 CD34+ cells per kg body weight of the animal with &gt;80% purity. Collected CD34+ cells are stored in liquid nitrogen. These cells will be prestimulated for 24 hours with huSCF, huFlt3L, huIL-6 and huTPO (kindly provided by Amgen) and will be transduced with a concentrated bicistronic lentivector (LV) that engineers co-expression of huα-gal A and huCD25, a cell surface marker for transduced cells. Our lab has recently shown overexpression of a rhesus form of CD25 in &gt;80% of transduced rhesus BM CD34+ cells mediated by a LV, validating its candidacy as a marker gene. Transduced cells will then be transplanted autologously in the NHPs after myeloablation by irradiation (10Gy) or mild chemotherapy (fludarabine and cyclophosphamide). The irradiation protocol has been optimized and a special plexiglass chamber, with the capacity for inhalational and intravenous anesthesia as well as a space for a HEPA filter, has been prepared for the animal procedures. The transplanted animals will be followed for at least one year and outcomes will be assessed by full measurement of safety parameters, α-gal A activity in plasma and relevant organs along with the real-time PCR and LAM PCR on BM and peripheral blood cells for the persistence of LV. Gb3 levels will also be examined in different organs compared to pre-transplant levels in tissue biopsies. We expect that this preclinical study in NHPs will serve as a roadmap to clinical gene therapy of Fabry disease using LV and provide important safety information for the use of this promising gene delivery system.

Plerixafor Single Agent for Autologous Stem Cells Mobilization and Collection in Adult Thalassemic Patients: Towards the Assessment of the Suitable Hematopoietic Stem Cell Source for Gene Therapy of Beta-Thalassemia.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 586-586
Author(s):  
Marta Claudia Frittoli ◽  
Bernhard Gentner ◽  
Maria Rosa Lidonnici ◽  
Annamaria Aprile ◽  
Laura Bellio ◽  
...  
Keyword(s):  
Stem Cells ◽  
Gene Therapy ◽  
Steady State ◽  
Peripheral Blood ◽  
Single Agent ◽  
Beta Thalassemia ◽  
Target Cells ◽  
Beta Globin ◽  
Hematopoietic Stem ◽  
Cd34 Cells

Abstract Abstract 586 Gene therapy of inherited blood diseases requires harvest of hematopoietic stem cells (HSCs) from patients and autologous transplantation of genetically modified cells. In order to achieve correction of the disease, high number of HSCs and previous conditioning of the host bone marrow (BM) are necessary. In the clinical application of gene therapy for thalassemic patients the choice of the HSC source is a crucial issue. On one side, the minimal target dose poses a challenge for the use of steady state BM since reinfusion of high numbers of beta globin gene modified CD34+ cells is probably necessary to gain sufficient correction of the genetic defect in order to achieve transfusion independency; on the other side, the disease related features and complications of thalassemic patients (i.e. splenomegaly and thrombophilia) dictate caution in the use of G-CSF as mobilizing agent. In April 2011 a clinical protocol exploring the use of Plerixafor (AMD3100) as single agent was started (“Plerixafor mobilized stem cells as source for gene therapy of beta-thalassemia”, acronym AMD-THAL, EudraCT2011-000973-30). Aims of the trial were to explore the ability of Plerixafor in inducing safe and effective stem cells mobilization in adult patients affected by beta-thalassemia, to characterize stem/progenitor cells mobilized from the BM and peripheral blood of treated subjects and to achieve gene transfer efficiency of mobilized CD34+ cells at a level comparable to that obtained using steady state BM. Four patients (01, 02, 03 and 04) were enrolled and already mobilized to date (August 2012). All patients are affected by transfusion dependent beta-thalassemia and aged 28 (01), 41 (02), 39 (03), 33 (04). Two are splenectomized (02 and 03); all subjects are regularly iron chelated with adequate organ function. Administration of Plerixafor subcutaneously as single agent and at the single dose of 0.24 mg/kg resulted in mobilization of CD34+ cells/mcl with a peak of 78 cells at 9 hrs (01), 70 cells at 7 hrs (02) and 69 cells at 8 hrs (03); suboptimal mobilization was observed in patient 04 (peak 18 at 8 hrs). Patient 03 received a second dose at 0.40 mg/kg 24 hrs after the first dose and underwent a second leucoapheretic procedure. Harvest by leukoapharesis resulted in procurement of the following CD34+ cells/kg: 1.84 × 106 (01) and 4.43 × 106 (02) with a unique leukoapheretic procedure, and 3.57 × 106 (03) with two leukoapheresis. No apheresis was performed for patient 04 because the minimum target of 20 CD34+ cells/mcl in peripheral blood was not reached. CD34+ cells selection through Clinimacs Miltenyi resulted in the following yield: 1.2 × 106 CD34+ cells/Kg, 65% recovery (01), 2.66 × 106 CD34+ cells/Kg, 60% recovery (02), 1.78 × 106 CD34+ cells/Kg, 50% recovery (03). No severe adverse event occurred. Recorded side effects were: grade 3 hypotension related to the apheretic procedure (01), mild grade 1 facial disestesia (02 and 04) and hyperleukocytosis (02: WBC from 13.6 to 42.6 × 103/mcl). In addition, steady state and Plerixafor primed BM aspirates were performed to analyze any modification in CD34+ concentration in the BM following Plerixafor administration. In fact, Plerixafor administration resulted in enrichment of CD34+ cells concentration in the BM. Purified CD34+ cells from leukoapheresis of the 4 treated patients were analyzed for their biological and functional properties, subpopulations composition and expression profile. In vivo reconstitution potential and lymphomyeloid differentiation of CD34+ cells were tested following transplantation in NSG mice. Experiments are ongoing but preliminary results indicate that cells mobilized by Plerixafor have a primitive phenotype with a high reconstitution potential and are efficiently transduced with a lentiviral based vector, named GLOBE, encoding for the human beta-globin (Roselli et al., 2010), thus being a suitable source of target cells for gene therapy. Disclosures: No relevant conflicts of interest to declare.

The Challenge Of HSCs Procurement For Gene Therapy: Exploring Plerixafor As Mobilization Agent

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2901-2901
Author(s):  
Maria Rosa Lidonnici ◽  
Annamaria Aprile ◽  
Marta Claudia Frittoli ◽  
Giacomo Mandelli ◽  
Bernhard Gentner ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Peripheral Blood ◽  
Conflicts Of Interest ◽  
Transduction Efficiency ◽  
Beta Thalassemia ◽  
Hematopoietic Stem ◽  
Cell Dose ◽  
Nsg Mice ◽  
Molecular Features ◽  
Cd34 Cells

Abstract Successful gene therapy of inherited blood diseases relies on transplantation and engraftment of autologous genetically engineered hematopoietic stem/progenitor cells (HSPCs) in myeloablated patients. Hematopoietic reconstitution and clinical benefit are related to cell dose, although single disease features might play a role favoring selection of relevant progenitor populations. Gene therapy trials in young pediatric patients are performed isolating CD34+ cells from bone marrow (BM), while in adults mobilized peripheral blood stem cells (PBSC) should represent the favorite target. In the context of gene therapy for thalassemia, the choice of HSPC source is crucial since intrinsic characteristics of patients (splenomegaly and thrombophilia) dictate caution in the use of G-CSF as mobilization agent and prompt investigation of new agents. Moreover, adult thalassemic patients may possibly have a decreased BM stem cell reservoir, due to the BM suppression in response to multiple transfusions. A phase II clinical protocol exploring the use of Plerixafor as a single mobilizing agent in adult patients affected by transfusion dependent beta-thalassemia (EudraCT 2011-000973-30) started in 2012 at our hospital. Plerixafor selectively and reversibly antagonizes the binding of SDF-1 to its receptor CXCR4 with subsequent egress of HSCs to the peripheral blood. The availability of a new source of HSPCs, potentially superior in terms of CD34+ cell yield, transduction efficiency and biological features to steady-state BM, would have a significant impact on the feasibility and efficacy of gene therapy. Four subjects were enrolled and treated by subcutaneously administration of Plerixafor at the single dose of 0.24 mg/kg followed by leukoapheresis. Mobilization of CD34+ cells occurred very rapidly with a peak between 7 to 9 hrs. Three out of four patients achieved the minimal target cell dose (2 x 106 cells/kg) and no severe adverse event occurred. To the aim of engineering Plerixafor-mobilized CD34+ cells for gene therapy, we performed a comprehensive characterization of their biological, molecular and functional properties. In vivo reconstitution potential and lympho-myeloid differentiation were tested following transplantation in NSG mice and compared to those of PBSCs mobilized by G-CSF. Percentages of engrafted human cells in NSG mice transplanted with Plerixafor -PBSCs were about 2- to 5-fold higher than those found in mice transplanted with G-CSF PBSCs. On the same line, the SRC frequency, obtained by pooled engraftment data, was significantly higher (1 SRC out of 47.875 CD34+ cells vs.1 SRC out of 141.203 CD34+ cells). The phenotypic analysis of the frequency of primitive hematopoietic sub-populations revealed that Plerixafor mobilizes preferentially HSPCs and LT-HSPCs, with a percentage of CD34+ CD38-/low CD90+ CD45RA- CD49f+ cells higher than that found in G-CSF PBSCs. This result mirrors the enhanced number of SRCs found in the CD34+ cell population mobilized by Plerixafor. In order to further define the molecular features of HSPCs from different sources, we are studying signalling networks in response to specific cytokines by phospho-proteins analysis and gene expression by microarrays analysis. Our studies are focused on self-renewal, homing, engraftment and multilineage differentiation processes and bioinformatic analysis will reveal the molecular machinery underlying 'stemness' properties of Plerixafor mobilized cells. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Lower Hematopoietic Progenitor Cell Counts and Yields at Subsequent Donations Is Influenced By a Shorter Inter-Donation Interval between the First and Subsequent Mobilizations

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1962-1962
Author(s):  
Sandhya R. Panch ◽  
Brent R. Logan ◽  
Jennifer A. Sees ◽  
Bipin N. Savani ◽  
Nirali N. Shah ◽  
...  
Keyword(s):  
Stem Cell ◽  
Board Of Directors ◽  
Peripheral Blood ◽  
Research Funding ◽  
Time Interval ◽  
Advisory Committees ◽  
Hematopoietic Stem ◽  
Peripheral Blood Cd34 ◽  
Cell Counts ◽  
Cd34 Cells

Introduction: Approximately 7% of unrelated hematopoietic stem cell (HSC) donors are asked to donate a subsequent time to the same or different recipient. In a recent large CIBMTR study of second time donors, Stroncek et al. incidentally found that second peripheral blood stem cell (PBSC) collections had lower total CD34+ cells, CD34+ cells per liter of whole blood processed, and CD34+ cells per kg donor weight. Based on smaller studies, the time between the two independent PBSC donations (inter-donation interval) as well as donor sex, race and baseline lymphocyte counts appear to influence CD34+ cell yields at subsequent donations. Our objective was to retrospectively evaluate factors contributory to CD34+ cell yields at subsequent PBSC donation amongst NMDP donors. Methods. The study population consisted of filgrastim (G-CSF) mobilized PBSC donors through the NMDP/CIBMTR between 2006 and 2017, with a subsequent donation of the same product. evaluated the impact of inter-donation interval, donor demographics (age, BMI, race, sex, G-CSF dose, year of procedure, need for central line) and changes in complete blood counts (CBC), on the CD34+ cell yields/liter (x106/L) of blood processed at second donation and pre-apheresis (Day 5) peripheral blood CD34+ cell counts/liter (x106/L) at second donation. Linear regression was used to model log cell yields as a function of donor and collection related variables, time between donations, and changes in baseline values from first to second donation. Stepwise model building, along with interactions among significant variables were assessed. The Pearson chi-square test or the Kruskal-Wallis test compared discrete variables or continuous variables, respectively. For multivariate analysis, a significance level of 0.01 was used due to the large number of variables considered. Results: Among 513 PBSC donors who subsequently donated a second PBSC product, clinically relevant decreases in values at the second donation were observed in pre-apheresis CD34+ cells (73.9 vs. 68.6; p=0.03), CD34+cells/L blood processed (32.2 vs. 30.1; p=0.06), and total final CD34+ cell count (x106) (608 vs. 556; p=0.02). Median time interval between first and second PBSC donations was 11.7 months (range: 0.3-128.1). Using the median pre-apheresis peripheral blood CD34+ cell counts from donation 1 as the cut-off for high versus low mobilizers, we found that individuals who were likely to be high or low mobilizers at first donation were also likely to be high or low mobilizers at second donation, respectively (Table 1). This was independent of the inter-donation interval. In multivariate analyses, those with an inter-donation interval of >12 months, demonstrated higher CD34+cells/L blood processed compared to donors donating within a year (mean ratio 1.15, p<0.0001). Change in donor BMI was also a predictor for PBSC yields. If donor BMI decreased at second donation, so did the CD34+cells/L blood processed (0.74, p <0.0001). An average G-CSF dose above 960mcg was also associated with an increase in CD34+cells/L blood processed compared to donors who received less than 960mcg (1.04, p=0.005). (Table 2A). Pre-apheresis peripheral blood CD34+ cells on Day 5 of second donation were also affected by the inter-donation interval, with higher cell counts associated with a longer time interval (>12 months) between donations (1.23, p<0.0001). Further, independent of the inter-donation interval, GCSF doses greater than 960mcg per day associated with higher pre-apheresis CD34+ cells at second donation (1.26, p<0.0001); as was a higher baseline WBC count (>6.9) (1.3, p<0.0001) (Table 2B). Conclusions: In this large retrospective study of second time unrelated PBSC donors, a longer inter-donation interval was confirmed to be associated with better PBSC mobilization and collection. Given hematopoietic stem cell cycling times of 9-12 months in humans, where possible, repeat donors may be chosen based on these intervals to optimize PBSC yields. Changes in BMI are also to be considered while recruiting repeat donors. Some of these parameters may be improved marginally by increasing G-CSF dose within permissible limits. In most instances, however, sub-optimal mobilizers at first donation appear to donate suboptimal numbers of HSC at their subsequent donation. Disclosures Pulsipher: CSL Behring: Membership on an entity's Board of Directors or advisory committees; Miltenyi: Research Funding; Bellicum: Consultancy; Amgen: Other: Lecture; Jazz: Other: Education for employees; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Medac: Honoraria. Shaw:Therakos: Other: Speaker Engagement.

The Common Marmoset as a Target Preclinical Primate Model for Cytokine and Gene Therapy Studies

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 2839-2848 ◽  
Author(s):  
Hitoshi Hibino ◽  
Kenzaburo Tani ◽  
Kenji Ikebuchi ◽  
Ming-Shiuan Wu ◽  
Hajime Sugiyama ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Gene Transfer ◽  
Progenitor Cells ◽  
Nonhuman Primate ◽  
Peripheral Blood ◽  
Common Marmoset ◽  
Transduction Efficiency ◽  
Hematopoietic Stem ◽  
The Common

Nonhuman primate models are useful to evaluate the safety and efficacy of new therapeutic modalities, including gene therapy, before the inititation of clinical trials in humans. With the aim of establishing safe and effective approaches to therapeutic gene transfer, we have been focusing on a small New World monkey, the common marmoset, as a target preclinical model. This animal is relatively inexpensive and easy to breed in limited space. First, we characterized marmoset blood and bone marrow progenitor cells (BMPCs) and showed that human cytokines were effective to maintain and stimulate in culture. We then examined their susceptibility to transduction by retroviral vectors. In a mixed culture system containing both marmoset stromal cells and retroviral producer cells, the transduction efficiency into BMPCs and peripheral blood progenitor cells (PBPCs) was 12% to 24%. A series of marmosets then underwent transplantation with autologous PBPCs transduced with a retroviral vector carrying the multidrug resistance 1 gene (MDR1) and were followed for the persistence of these cells in vivo. Proviral DNA was detectable by polymerase chain reaction (PCR) in peripheral blood granulocytes and lymphocytes in the recipients of gene transduced progenitors up to 400 days posttransplantation. To examine the function of the MDR1 gene in vivo, recipient maromsets were challenged with docetaxel, an MDR effluxed drug, yet the overall level of gene transfer attained in vivo (<1% in peripheral blood granulocytes) was not sufficient to prevent the neutropenia induced by docetaxel treatment. Using this model, we safely and easily performed a series of in vivo studies in our small animal center. Our results show that this small nonhuman primate, the common marmoset, is a useful model for the evaluation of gene transfer methods targeting hematopoietic stem cells.

Gene Therapy Targeting Peripheral Blood CD34+Hematopoietic Stem Cells of HIV-infected Individuals

1997 ◽  
Vol 8 (18) ◽  
pp. 2229-2238 ◽  
Author(s):  
A. Gervaix ◽  
L. Schwarz ◽  
P. Law ◽  
A. D. Ho ◽  
D. Looney ◽  
...  
Keyword(s):  
Stem Cells ◽  
Gene Therapy ◽  
Hematopoietic Stem Cells ◽  
Peripheral Blood ◽  
Hematopoietic Stem ◽  
Peripheral Blood Cd34

scholarly journals Absolute numbers of peripheral blood CD34+ hematopoietic stem cells prior to a leukapheresis procedure as a parameter predicting the efficiency of stem cell collection

2017 ◽  
Vol 89 (7) ◽  
pp. 18-24 ◽  
Author(s):  
I V Galtseva ◽  
Yu O Davydova ◽  
T V Gaponova ◽  
N M Kapranov ◽  
L A Kuzmina ◽  
...  
Keyword(s):  
Stem Cells ◽  
Body Weight ◽  
Hematopoietic Stem Cells ◽  
Peripheral Blood ◽  
Close Correlation ◽  
Blood Leukocytes ◽  
Hematopoietic Stem ◽  
Peripheral Blood Cd34 ◽  
Cd34 Cells ◽  
Stem Cell Collection

Aim. To identify a parameter predicting a collection of at least 2·106 CD34+ hematopoietic stem cells (HSC)/kg body weight per leukapheresis (LA) procedure. Subjects and methods. The investigation included 189 patients with hematological malignancies and 3 HSC donors, who underwent mobilization of stem cells with their subsequent collection by LA. Absolute numbers of peripheral blood leukocytes and CD34+ cells before a LA procedure, as well as a number of CD34+ cells/kg body weight (BW) in the LA product stored on the same day were determined in each patient (donor). Results. There was no correlation between the number of leukocytes and that of stored CD34+ cells/kg BW. There was a close correlation between the count of peripheral blood CD34+ cells prior to LA and that of collected CD34+ cells calculated with reference to kg BW. Conclusion. The optimal absolute blood CD34+ cell count was estimated to 20 per µl, at which a LA procedure makes it possible to collect 2·106 or more CD34+ cells/kg BW.

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