Neonatal sex and weight influence CD34(+) cell concentration in umbilical cord blood but not stromal cell-derived factor 1-3'A polymorphism.

BACKGROUND: Umbilical cord blood (UCB) has been used as an alternative source of donor hematopoietic stem cells for hematologic transplant setting over the past decade. This study attempted to evaluate potential predictors of cord blood quality. METHODS: A total of 750 UCB samples were studied (male, n = 365; female, n = 385). The impact of neonatal sex, weight and stromal cell-derived factor-1α polymorphism on the quality of these UCB samples was investigated. RESULTS: Male neonatal UCB was significantly richer in CD34(+) cells than was female UCB (P < 0.001), whereas female UCB was richer in total nucleated cells (P = 0.01). There was a slight correlation between CD34(+) cells concentration and UCB sample weight (P < 0.01) that could be attributed to the higher weight of male neonates. The use of tetra-polymerase chain reaction to detect stromal cell-derived factor-1α polymorphisms in 180 neonates revealed no differences between A/A, G/G and A/G allelic combinations. CONCLUSIONS: These data emphasize the lack of predictive factors for CD34(+) cells and total nucleated cell concentrations in UCB samples before processing.

Thrombopoietin to replace megakaryocyte-derived growth factor: impact on stem and progenitor cells during ex vivo expansion of CD34+ cells mobilized in peripheral blood.

BACKGROUND: The first protocol of ex vivo expansion that enabled almost total abrogation of postmyeloablative chemotherapy neutropenia was based on a three-cytokine cocktail (stem cell factor [SCF], granulocyte-colony-stimulating factor [G-CSF], pegylated-megakaryocyte growth and development factor [PEG-MGDF]) in a serum-free medium. Since the clinical-grade molecule MGDF is no longer available on the market, we evaluated its substitution by thrombopoietin (TPO). STUDY DESIGN AND METHODS: CD34+ cells of myeloma patients were expanded for 10 days in serum-free cultures with SCF, G-CSF, or MGDF (100 ng/mL) or with TPO (2.5, 10, 20, 50, and 100 ng/mL) instead of MGDF. Day 10 amplifications of total nucleated cells, CD34+ cells, committed progenitors (CFCs), the capacity of engraftment of NOD/SCID mice (SCID repopulating cells [SRCs]), and the immunophenotype of cells in expansion product (CD13, CD14, CD33, CD41, CD61) were analyzed. RESULTS: TPO in doses of 2.5 and 10 ng/mL exhibits an effect comparable to that of MGDF (100 ng/mL) on total, CD34+, and CFCs amplification. Compared to MGDF, TPO (starting at 10 ng/mL) enhances two- to threefold the percentage of megakaryocyte lineage cells (CD41+ and CD61+). Finally, TPO maintains or even enhances (depending on dose) SRC activity. CONCLUSIONS: The use of TPO instead of MGDF in our protocol is feasible without any negative effect on progenitor cell expansion. Furthermore, applied in dose of 10 or 100 ng/mL it could enhance both the stem cell activity and the percentage of megakaryocyte lineage cells in expansion product.

Umbilical cord blood transplants facilitated by the French cord blood banks network. On behalf of the Agency of Biomedicine, Eurocord and the French society of bone marrow transplant and cell therapy (SFGM-TC).

The public French Cord Blood Banks Network was established in 1999 with the objective of standardizing the practices governing umbilical cord blood (UCB) banking in France. The Network adopted a strategy to optimize its inventory and improve the quality of its banked units based on a quality improvement process using outcome data regularly provided by Eurocord. This study aimed to describe the results, over 10 years, of UCBT facilitated by a national network that used the same criteria of UCB collection and banking and to assess how modifications of banking criteria and unit selection might influence transplant outcomes. Nine hundred and ninety-nine units (593 single-unit and 203 double-unit grafts) were released by the Network to transplant 796 patients with malignant (83%) and non-malignant (17%) diseases. Median cell dose exceeded 3.5 × 107 TNC/kg in 86%. There was a trend to select units more recently collected and with higher cell dose. Neutrophil engraftment was 88.2% (85.7-90.7) and 79.3% (72.6-86.5) respectively for malignant and non-malignant diseases with a trend to faster recovery with higher cell doses. The respective 3-year transplant-related mortality were 31.1% (27.5-35.1) and 34.3% (27.0-43.5). OS was 49% ± 4 in malignant and 62% ± 4 in non-malignant disorders. In multivariate analysis, cell dose was the only unit-related factor associated with outcomes. Our results reflect the benefit on clinical outcomes of the strategy adopted by the Network to bank units with higher cell counts.

A novel procedure to improve functional preservation of hematopoietic stem and progenitor cells in cord blood stored at +4°c before cryopreservation.

During storage and transportation of collected cord blood units (CBUs) to the bank prior to their processing and cryopreservation, it is imperative to preserve the functional capacities of a relatively small amount of cells of interest (stem and progenitor cells) which are critical for graft potency. To improve CBU storage efficiency, we conceived an approach based on the following two principles: (1) to provide a better nutritive and biochemical environment to stem and progenitor cells in CB and (2) to prevent the hyperoxygenation of these cells transferred from a low- (1.1%-4% O2 in the CB) to a high-oxygen (20%-21% O2 in atmosphere) concentration. Our hypothesis is confirmed by the functional assessment of stem cell (hematopoietic reconstitution capacity in immunodeficient mice-scid repopulating cell assay) and committed progenitor activities (capacity of in vitro colony formation and of ex vivo expansion) after the storage period with our medium (HP02) in gas-impermeable bags. This storage procedure maintains the full functional capacity of a CBU graft for 3 days with respect to day 0. Further, using this procedure, a graft stored 3 days at +4°C exhibits better functional capacities than one currently used in routine storage (CBUs stored at +4°C for 1 day in gas-permeable bags and without medium). We provided the proof of principle of our approach, developed a clinical-scale kit and performed a preclinical assay demonstrating the feasibility and efficiency of our CBU preservation protocol through all steps of preparation (volume reduction, freezing, and thawing).

Definitive setup of clinical scale procedure for ex vivo expansion of cord blood hematopoietic cells for transplantation.

We recently developed a clinical grade ex vivo cord blood expansion procedure enabling a massive amplification of hematopoietic progenitors without any loss of stem cell potential. This procedure, based on day 14 liquid cultures of cord blood CD34(+) cells, in medium Macopharma HP01 and in the presence of stem cell factor (SCF; 100 ng/ml), fms-related tyrosine kinase 3-ligand (Flt-3L; 100 ng/ml), megakaryocyte growth and developmental factor (MGDF; 100 ng/ml), and granulocyte colony-stimulating factor (G-CSF; 10 ng/ml) had to be modified due to the commercially unavailability of clinical grade MGDF molecule. So MGDF was replaced by thrombopoietin (TPO) in fivefold lower dose (20 ng/ml), and culture time was reduced to 12 days. That way, a mean expansion fold of 400, 80, and 150 was obtained for total cells, CD34(+) cells, and colony-forming cells (CFCs), respectively. This amplification was associated with a slight enhancing effect on stem cells [Scid repopulating cells (SRCs)]. These are the ultimate preclinical modifications of a clinical grade expansion protocol, which is already employed in an ongoing clinical trial.

Clinical-scale cultures of cord blood CD34(+) cells to amplify committed progenitors and maintain stem cell activity.

We developed a clinical-scale cord blood (CB) cell ex vivo procedure to enable an extensive expansion of committed progenitors--colony-forming cells (CFCs) without impairing very primitive hematopoietic stem cells (HSCs). CD34(++) cells, selected from previously cryopreserved and thawed CB units, were cultured in two steps (diluted 1:4 after 6 days) in the presence of stem cell factor (SCF), fms-related tyrosine kinase 3 ligand (Flt-3L), megakaryocyte growth and development factor (MGDF) (100 ng/ml each), granulocyte-colony stimulating factor (G-CSF) (10 ng/ml) in HP01 serum-free medium. HSC activity was evaluated in a serial transplantation assay, by detection of human cells (CD45, CD33, CD19 and CFC of human origin) in bone marrow (BM) of primary and secondary recipient NOD/SCID mice 6-8 weeks after transplantation. A wide amplification of total cells (∼350-fold), CD34(+) cells (∼100-fold), and CFC (∼130-fold) without impairing the HSC activity was obtained. The activity of a particular HSC subpopulation (SRC(CFC)) was even enhanced.Thus, an extensive ex vivo expansion of CFCs is feasible without impairing the activity of HSCs. This result was enabled by associating antioxidant power of medium with an appropriate cytokine cocktail (i.e., mimicking physiologic effects of a weak oxygenation in hematopoietic environment).

Whole-blood leuko-depletion filters as a source of CD 34+ progenitors potentially usable in cell therapy.

BACKGROUND: Used leuko-depletion filters (LDFs), containing billions of white blood cells (WBCs), are discarded. Because the steady-state blood contains low quantities of stem and progenitor cells that are retained in LDFs, the viability and the functional properties of mononuclear cells (MNCs) and CD 34+ cells recovered from LDFs were investigated. STUDY DESIGN AND METHODS: WBCs were recovered from LDFs by use of a closed system. MNCs and CD 34+ cells were isolated from freshly LDF-recovered WBCs or after their overnight incubation. The CD 34+ cells were enumerated, as well as the number of colony-forming unit (CFU)-granulocyte-macrophage, burst-forming unit-erythroid, and CFU-Mixed. The expansion in clinical-scale volume cultures (serum-free medium plus stem cell factor, granulocyte-colony-stimulating factor, and megakaryocyte growth and development factor) was performed starting from MNCs, freshly isolated CD 34+ cells, and CD 34+ cells isolated after overnight incubation of WBCs. The erythroid, megakaryocytic, eosinophilic, and monocyte-myelocytic lineage differentiation of LDF-recovered CD 34+ cells was challenged in liquid cultures by adding relevant cytokines. RESULTS: Nearly 450 x 10(3) viable CD 34+ cells were recovered per LDF. These cells exhibit unimpaired colony-forming ability. It is possible to expand these cells ex vivo, but their response to cytokines is different compared to mobilized peripheral blood and cord blood CD 34+ cells. Thus, further work is necessary to optimize their ex vivo expansion. These cells give rise to the mature cells and precursors of erythroid, megakaryocytic, eosinophilic, and monomyelocytic lineage in liquid cultures. CONCLUSION: MNCs and CD 34+ cells recovered from the LDFs exhibit unimpaired functional capacities. Recent development of ex vivo technologies for expansion, retro-differentiation, and differentiation reinforces the value in cell therapy of these LDG-recovered peripheral blood progenitor cells that are routinely discarded.

A clinical-scale expansion of mobilized CD 34+ hematopoietic stem and progenitor cells by use of a new serum-free medium.

BACKGROUND: The autologous transplantation of CD 34+ cells expanded ex vivo in serum-free conditions dramatically reduces post-myeloablative neutropenia in myeloma patients. In our cell therapy unit, cells for this clinical assay have been expanded under GMP with serum-free Irvine Scientific (IS) medium with stem cell factor (SCF), granulocyte-colony-stimulating factor (G-CSF), and megakaryocyte growth and development factor (MGDF; 100 ng/mL, respectively). Because this clinical-grade IS medium is no longer available, a new serum-free medium, Maco Biotech HP 01 (Macopharma), was evaluated. STUDY DESIGN AND METHODS: Purified CD 34+ cells (Isolex 300i, Baxter) from mobilized peripheral blood samples of myeloma patients were thawed, washed, and cultured, as for previous clinical assays. Twenty million CD 34+ cells were resuspended per 1 L of SCF-, G-CSF-, and MGDF-supplemented medium (HP 01 or IS), introduced into 3-L culture bags (AFC), and cultured for 10 days in 5 percent CO(2), at 37 degrees C, and at 100 percent humidity. RESULTS: A higher amplification of total nucleated cells (NCs) and colony-forming cells (CFCs) was obtained with HP 01 medium than with IS medium (42+/-16.6-fold vs. 20.5+/-5.9-fold for NCs and 26.7+/-7.4-fold vs. 15.5+/-2.5-fold for CFCs, respectively), whereas an increase in CD 34+ cells (3.5+/- 1.2-fold for HP 01 vs. 2.7+/- 1.5-fold for IS) was not significant. IS medium partially maintained SCID-repopulating cells (SRC), whereas the culture in HP 01 medium fully maintained the stem cell activity for 10 days. A higher frequency of CD 41+ cells after expansion in HP 01 than in IS medium was also observed. CONCLUSION: Maco Biotech HP 01 medium is suitable for clinical-scale expansion of CD 34+ cells with the SCF, G-CSF, and MGDF cytokine cocktail, permitting an intensive amplification of CFCs and maintenance of SRCs.

Large-scale expansion and transplantation of CD34(+) hematopoietic cells: in vitro and in vivo confirmation of neutropenia abrogation related to the expansion process without impairment of the long-term engraftment capacity.

BACKGROUND: Herein are reported the results obtained in all multiple myeloma patients transplanted with peripheral blood hematopoietic progenitor cells submitted to ex vivo expansion. STUDY DESIGN AND METHODS: Patients had blood progenitor cell mobilization with cyclophosphamide and filgrastim. CD34+ cells were expanded for 10 days in a medium containing granulocyte-colony-stimulating factor (G-CSF), stem cell factor, and megakaryocyte growth and development factor (MGDF). Twenty-seven patients underwent transplantation with expanded and nonexpanded cells and 7 patients underwent transplantation with expanded cells only. RESULTS: The median fold cell expansion was 29.1. The number of colony-forming unit-granulocyte-macrophage (CFU-GM) and CD34+ cells, and the long-term culture-initiating cell (LTC-IC) activity increased with median fold values of 14.7, 2.75, and 2.25, respectively. Postmyeloablative neutropenia was abrogated in 24 of 27 patients transplanted with expanded cells plus nonexpanded cells. The median duration of severe neutropenia was 0 days and correlated with the number of cells and CFU-GM infused. Survival was similar to that of a historical control group. Our LTC-IC and NOD-SCID mice studies showed that the expanded cells are able of sustaining long-term hematopoiesis. Seven other patients received transplantation with expanded cells alone. Absolute neutropenia was abrogated in 6 patients. The median duration of neutropenia was 0 days. Two patients who received the lower number of total cells or CFU-GM had brief secondary neutropenia, which resolved after G-CSF injections. CONCLUSION: CD34+ cells expanded ex vivo can abrogate absolute and severe neutropenia after high-dose therapy. The results of the amplification process are strongly related to the delay of hematopoietic recovery.

Comparison of CD34+ cell collection on the CS-3000+ and Amicus blood cell separators.

BACKGROUND: Mobilized PBPCs, detectable on the basis of CD34 expression, can be collected on various cell separators. The CD34+ cell collection efficiencies of two cell separators (CS-3000+ and Amicus, Baxter) were tested on two comparable groups of oncology patients. STUDY DESIGN AND METHODS: Leukapheresis assisted by the standard manufacturer's software and variables settings was performed in 37 (CS-3000+) and 34 (Amicus) patients (total of 83 and 67 collections, respectively) after chemotherapy plus G-CSF treatment. RESULTS: The total CD34+ cell count per leukapheresis components as well as per kg of patient's body weight were twofold higher by using the Amicus than the CS-3000+ device. Platelet contamination in Amicus components was twice as low compared to the CS3000+. Mean Amicus CD34+ collection efficiency (CD34+eff) (54.9 +/- 27.2%) was significantly higher (p < 0.015) than the CS-3000+ (46.4 +/- 16.7%) one. However, Amicus CD34+eff decreased progressively as the peripheral blood CD34+ concentrations increases over 200 CD34+ cells per microL. A parallel increase in the WBC counts in these cases seems to be the principal cause of decrease in CD34+eff (evident for WBCs >40 x 10(3)/microL and most pronounced for WBCs >60 x 10(3)/microL). CONCLUSIONS: Mean CD34+eff and CD34+ cell yields were better on Amicus than on CS-3000+. CD34+eff of Amicus, however, seems to be related to the initial WBC counts, decreasing progressively when WBC increased over 4 x 10(3) per microL that coincided with the increase in CD34+ cell concentrations. For these cases, the volume and duration of cycles should be adapted to optimize CD34+ collections by using Amicus separators.

Simultaneous maintenance of human cord blood SCID-repopulating cells and expansion of committed progenitors at low O2 concentration (3%).

In the present work, we tested the hypothesis that liquid cultures (LCs) of cord blood CD34+ cells at an appropriate low O2 concentration could simultaneously allow colony-forming cell (CFC) expansion and nonobese diabetic/severe combined immunodeficiency mice-repopulating cell (SRC) maintenance. We first found that 3% was the minimal O2 concentration, still allowing the same rate of CFC expansion as at 20% O2. We report here that 7-day LCs of cord blood CD34+ cells at 3% O2 maintain SRC better than at 20% O2 and allow a similar amplification of CFCs (35- to 50-fold) without modifying the CD34+ cell proliferation. Their phenotypic profile (antigens: HLA-DR, CD117, CD33, CD13, CD11b, CD14, CD15, and CD38) was not modified, with exception of CD133, whose expression was lower at 3% O2. These results suggest that low O2 concentrations similar to those found in bone marrow participates in the regulation of hematopoiesis by favoring stem cell-renewing divisions. This expansion method that avoids stem cell exhaustion could be of paramount interest in hematopoietic transplantation by allowing the use of small-size grafts in adults.