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

Comparison of spectra optia and amicus cell separators for autologous peripheral blood stem cell collection

INTRODUCTION

Autologous peripheral blood stem cell (PBSC) transplantation has become a standard treatment option for many oncology patients. The aim of this study was to evaluate the performance of two cell separators, Spectra Optia (Terumo BCT, Japan) and Amicus (Fresenius-Kabi) for autologous PBSC collection.

METHODS

We retrospectively evaluated 56 apheresis by Spectra Optia with Continuous Mononuclear Cell Collection (cMNC) from 20 patients, and 50 apheresis by Amicus from 27 patients between December 2018 and December 2019. CD34+ collection efficiency (CE2) and platelet (PLT) loss were evaluated.

RESULTS

There was no significant difference in CD34+ CE2 between Spectra Optia with cMNC (median, 28.8%) and Amicus (median, 33.1%; P = 0.537). PLT loss was significantly lower in Amicus (median, 28.6%) than in Spectra Optia with cMNC (median, 37.8%; P = 0.009).

CONCLUSION

CD34+ CE2 was comparable between Spectra Optia and Amicus, and PLT loss was significantly lower in Amicus. To the best of our knowledge, this is the first report comparing autologous PBSC collection of the Spectra Optia and Amicus. These results may provide general guidance with regard to device selection to apheresis clinics that use both separators for optimal outcomes depending on each patient's characteristics.

Collection and immunoselection of CD34+ cells: the impact of age, sex, and diabetes in patients with chronic heart failure

BACKGROUND

Mobilized peripheral blood is the most common source of CD34+ cells intended for transplantations. The collection and enrichment of CD34+ cells could be affected by various factors and there are some controversies regarding the effects of patient-related factors. The aim of this study was to assess the impact of age, sex, and diabetes on the CD34+ cell grafts in patients with chronic heart failure.

STUDY DESIGN AND METHODS

Cell grafts from 100 adult patients scheduled for autologous CD34+ cell transplantation were investigated. The CD34+ cells were collected using leukapheresis after granulocyte-colony-stimulating factor mobilization and further enriched using the immunomagnetic CD34+ selection. The number of CD34+ cells and their viability were determined by flow cytometry.

RESULTS

Older patients had significantly lower CD34+ cell counts than younger patients. The differences between men and women were not found. There was a trend toward an inverse relationship between diabetes and the CD34+ cell count, however, without any significance. No differences in the CD34+ cell viability (97.6% before and 97.9% after selection) were found. The mean CD34+ cell recovery was 59.7% and was not statistically different between age groups, sex, and diabetic patients.

CONCLUSION

Before the CD34+ cells are collected the patient's age should be considered. The study did not demonstrate a significant impact of sex and diabetes on the CD34+ cell count. While age and sex did not affect the immunoselection process, diabetes slightly reduced cell recovery. Cell viabilities before and after the cell enrichment were comparable between the tested samples.

Autologous peripheral blood stem cell harvest: Collection efficiency and factors affecting it

BACKGROUND

Harvest of hematopoietic progenitor cells via leukapheresis is being used increasingly for transplants in India. Adequate yield of cells per kilogram body weight of recipient is required for successful engraftment. Collection efficiency (CE) is an objective quality parameter used to assess the quality of leukapheresis program. In this study, we calculated the CE of the ComTec cell separator (Fresenius Kabi, Germany) using two different formulae (CE1 and CE2) and analyzed various patient and procedural factors, which may affect it.

MATERIALS AND METHODS

One hundred and one consecutive procedures in 77 autologous donors carried out over 3 years period were retrospectively reviewed. Various characteristics like gender, age, weight, disease status, hematocrit, preprocedure total leukocyte count, preprocedure CD34 positive (CD34+) cells count, preprocedure absolute CD34+ cell count and processed apheresis volume effect on CE were compared. CE for each procedure was calculated using two different formulae, and results were compared using statistical correlation and regression analysis.

RESULTS

The mean CE1 and CE2 was 41.2 and 49.1, respectively. CE2 appeared to be more accurate indicator of overall CE as it considered the impact of continued mobilization of stem cells during apheresis procedure, itself. Of all the factors affecting CE, preprocedure absolute CD34+ was the only independent factor affecting CE.

CONCLUSION

The only factor affecting CE was preprocedure absolute CD34+ cells. Though the mean CE2 was higher than CE1, it was not statistically significant.

Functional Stability (at +4°C) of Hematopoietic Stem and Progenitor Cells Amplified Ex Vivo from Cord Blood CD34+ Cells

Our previously published ex vivo expansion procedure starting from cord blood CD34+ cells enables a massive expansion of total and CD34+ cells and committed progenitors without negative impact on stem cells exhibiting both short- and long-term repopulating capacity. It was upgraded to clinical scale [Macopharma HP01® medium in presence of SCF, FLT3-L (100 ng/ml each), G-SCF (10 ng/ml), and TPO (20 ng/ml)] and is in use for an ongoing clinical trial (adult allogeneic context), yielding encouraging results. In order to test the possibility to use the expanded cells in distant transplantation centers, we studied the functional stability at +4°C (usual temperature of transportation) of hematopoietic progenitors and stem cells 48 h after expansion. If the cells were washed and resuspended in 4% albumin solution (actual procedure for immediate injection), only one half of total nucleated and CD34+ cells and 30% of committed progenitors survived after 24 h. This condition has also an evident negative impact on stem cells in expansion product as demonstrated on the basis of reconstitution of NSG mice bone marrow by human CD45, CD33, CD19+ cells as well as by human committed progenitors (CFU). Surprisingly, if the cells were stored 48 h at +4°C in culture medium, very good survival of total and CD34+ cells (90 to 100%) and colony forming unit cells (CFCs; around 70%) was obtained, as well as the maintenance of stem cells (the same in vivo assay with NSG mice). These data point to the possibility of the maintenance of the full functional capacity of expanded grafts for 2 days, the time allowing for its transportation to any transplantation center worldwide.

Cryopreservation of hematopoietic stem and progenitor cells amplified ex vivo from cord blood CD34+ cells

BACKGROUND

Our ex vivo expansion procedure starting from cord blood (CB) CD34+ cells enabled expansion of committed progenitors (CPs) without a negative impact on hematopoietic stem cells (HSCs) exhibiting both short- and long-term repopulating capacity. Upgraded to clinical scale (Macopharma HP01 in the presence of stem cell factor, FLT3-L [100 ng/mL each], granulocyte-colony-stimulating factor [10 ng/mL], and thrombopoietin [20 ng/mL]), it is being used for an ongoing clinical trial (adult allogeneic context) yielding promising preliminary results. Transplantation of ex vivo expanded CB cells is becoming a reality, while the issue of expanded cells' cryopreservation emerges as an option that allows the conservation of the product for transportation and future use. Here, we investigated whether it is possible to maintain the functional HSC and CP properties after freezing and thawing of expanded cells.

STUDY DESIGN AND METHODS

We compared cryopreservation efficiency of the ex vivo expanded CB cells using the standard protocol (freezing solution human serum albumin (HSA)-dimethyl sulfoxide [DMSO]) with the newly designed protocol based on an enriched freezing solution (HP01-DMSO) with respect to the viability index, number of CD34+ and total cells, and recovery of CPs (colony-forming units) and HSCs (NOG/Scid/gamma-null mice engraftment).

RESULTS

Cryopreservation and thawing of expanded CB cells using the "standard" procedure (HSA-DMSO) reduced recovery of the CPs (40%) and HSCs (drastically decreasing engraftment capacity). HP01-based protocol resulted in improvement of preservation of both CPs (>60%) and HSCs (nonaltered engraftment capacities).

CONCLUSION

Functional maintenance of the expanded graft by cryopreservation is feasible in conditions compatible with human cell therapy requirements.

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.

Harvesting, processing and inventory management of peripheral blood stem cells

By 2003, 97% autologous transplants and 65% of allogeneic transplants in Europe used mobilised peripheral blood stem cells (PBSC). Soon after their introduction in the early 1990's, PBSC were associated with faster haemopoietic recovery, fewer transfusions and antibiotic usage, and a shorter hospital stay. Furthermore, ease and convenience of PBSC collection made them more appealing than BM harvests. Improved survival has hitherto been demonstrated in patients with high risk AML and CML. However, the advantages of PBSC come at a price of a higher incidence of extensive chronic GVHD. In order to be present in the blood, stem cells undergo the process of “mobilisation” from their bone marrow habitat. Mobilisation, and its reciprocal process – homing – are regulated by a complex network of molecules on the surface of stem cells and stromal cells, and enzymes and cytokines released from granulocytes and osteoclasts. Knowledge of these mechanisms is beginning to be exploited for clinical purposes. In current practice, stem cell are mobilised by use of chemotherapy in conjunction with haemopoietic growth factors (HGF), or with HGF alone. Granulocyte colony stimulating factor has emerged as the single most important mobilising agent, due to its efficacy and a relative paucity of serious side effects. Over a decade of use in healthy donors has resulted in vast experience of optimal dosing and administration, and safety matters. PBSC harvesting can be performed on a variety of cell separators. Apheresis procedures are nowadays routine, but it is important to be well versed in the possible complications in order to avoid harm to the patient or donor. To ensure efficient collection, harvesting must begin when sufficient stem cells have been mobilised. A rapid, reliable, standardized blood test is essential to decide when to begin harvesting; currently, blood CD34+ cell counting by flow cytometry fulfils these criteria. Blood CD34+ cell counts strongly correlate with the apheresis yields. These are, in turn, predictive of the speed of haemopoietic recovery after transplantation, which has helped establish the adequate cell dose for transplantation. Following collection, PBSC may be transfused unmanipulated, processed to select specific cell subtypes, or stored for future use. Cryopreservation techniques allow long term storage of stem cells without significant loss of viability. Increasingly demanding calls for safety led to introduction of vapour phase storage, separate storage of infected material, and mandatory quality control measures at all stages of the cryopreservation process and subsequent thawing and transfusion. At the same time, safety of the personnel working in stem cell processing and storage laboratories is safeguarded by a set of regulations devised to minimize the risk of infection, injury or hypoxia. Requirements for quality and safety have been shaped into a number of documents and directives in Europe and USA, emphasising the importance of product traceability, reporting of adverse reactions, quality management systems (standard operating procedures, guidelines, training records, reporting mechanisms and records), requirements for cell reception, quarantine, process control, validation and storage. Establishments that collect, process and store stem cells must be accredited or licensed by appropriate national or international authorities on a regular basis. These regulatory measures have recently become law across the European Union.

Low-oxygen and high-carbon-dioxide atmosphere improves the conservation of hematopoietic progenitors in hypothermia

BACKGROUND

During short-term storage of hematopoietic cells (HCs) at 4°C a substantial decline in number and in functional capacity of progenitors occurs after 3 days. We hypothesized that physiologic O2 and CO2 concentrations of hematopoietic tissue microenvironment (approx. 3% O2 and approx. 6% CO2) could improve cell viability and functionality during storage at 4°C.

STUDY DESIGN AND METHODS

Mobilized peripheral blood (PB) CD34+ cells from multiple myeloma or non-Hodgkin's lymphoma patients were stored in flasks containing air (approx. 20% O2 and approx. 0.05% CO2) or 3% O2/6% CO2 atmosphere, for 3, 5, and 7 days at 4°C. The total number of cells, the number of cells in G0 or G1 phase of cell cycle, and the apoptosis rate were determined. The functional capacity of stored cells was assessed by the capacity of progenitors to form colonies in methylcellulose (colony-forming cells [CFCs]) and of stem cells to repopulate the bone marrow (BM) of immunodeficient mice (SCI D-repopulating cell [SRC] assay).

RESULTS

The total number of viable cells and cells in G1 phase as well as the number of total CFCs were significantly higher at 3% O2/6% CO2 than in air at all time points. Cells in G0 phase and SRC were equally preserved in both conditions.

CONCLUSION

Atmosphere with low O2 and high CO2 concentration (3% O2/6% CO2) in hypothermia (+4°C) during 7 days of storage prevents cell damage and preserves a high number of functional HSCs and progenitors mobilized in PB by granulocyte-colony-stimulating factor.

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).

Current status of stem cell mobilization

New advances in effective mobilization of peripheral blood stem cells have permitted a greater proportion of patients to benefit from autologous stem cell transplantation. In this review, the relative merits of peripheral blood and mobilized bone marrow are discussed. All available agents are reviewed. A critical assessment of the appropriate dosing and frequency of available growth factors is undertaken, and the most commonly used chemotherapy plus growth factor combinations are covered. Specific recommendations for patients who are poor mobilizers are dealt with including the role of plerixafor.

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.

CD34+ cells obtained from "good mobilizers" are more activated and exhibit lower ex vivo expansion efficiency than their counterparts from "poor mobilizers"

BACKGROUND

The classification of patients into "good" or "poor" mobilizers is based on CD34+ cell count in their peripheral blood (PB) after granulocyte-colony-stimulating factor (G-CSF) injection. We hypothesized that, apart from their mobilization from marrow to the blood, the response to G-CSF of CD34+ cells also includes activation of proliferation, metabolic activity, and proliferative capacity.

STUDY DESIGN AND METHODS

Mobilized PB CD34+ cells purified from samples obtained by cytapheresis of multiple myeloma or non-Hodgkin's lymphoma patients of both good (>50 CD34+ cells/microL) and poor (< or =50 CD34+ cells/microL) mobilizers were studied. The initial cell cycle state of CD34+ cells after selection and their kinetics of activation (exit from G(0) phase) during ex vivo culture were analyzed. Their proliferative capacity was estimated on the basis of ex vivo generation of total cells, CD34+ cells, and colony-forming cells (CFCs), in a standardized expansion culture. Indirect insight in metabolic activity was obtained on the basis of their survival (viability and apoptosis follow-up) during the 7-day-long conservation in hypothermia (4 degrees C) in the air or in atmosphere containing 3% O(2)/6% CO(2).

RESULTS

CD34+ cells obtained from good mobilizers were in lower proportion in the G(0) phase, their activation in a cytokine-stimulated culture was accelerated, and they exhibited a lower ex vivo expansion efficiency than those from poor mobilizers. The resistance to hypothermia of good immobilizers' CD34+ cells is impaired.

CONCLUSION

A good response to G-CSF mobilization treatment is associated with a higher degree of proliferative and metabolic activation of mobilized CD34+ cells with a decrease in their expansion capacity.

Automated programs for collection of mononuclear cells and progenitor cells by two separators for peripheral blood progenitor cell transplantation: comparison by a randomized crossover study

BACKGROUND

Although automated programs have been increasingly used to collect peripheral blood (PB) progenitor cells (PBPCs), differences among them remain unclear. The automated programs of Amicus (Baxter Healthcare) and Spectra (software Version 6.1, Gambro BCT) apheresis machines were compared in a crossover study.

STUDY DESIGN AND METHODS

The patients for autologous and donors for allogeneic PBPC transplantation mobilized with granulocyte-colony-stimulating factor were randomly assigned into two groups. PBPCs were collected by the Amicus on the first day and the Spectra on the second of 2 consecutive days in Group I, and the reverse order was used in Group II. Of 39 patients or donors enrolled, 17 reached their collection goal with only one procedure and did not participate in the paired study. Thus, 44 paired procedures of the remaining 22 subjects were evaluated.

RESULTS

The product yields of white blood cells (WBCs; p < 0.005), mononuclear cells (MNCs; p < 0.02), and CD34+ PBPCs (p < 0.0002) from patients or donors were higher in the Amicus collections than those in the Spectra collections. The collection efficiencies of WBCs (p < 0.03), MNCs (p < 0.02), and CD34+ PBPCs (p < 0.03) were higher in the Amicus collections. The numbers of contaminating platelets (PLTs) in the Amicus collections were lower than those in the Spectra collections (p < 0.05) with a greater decrease in PB PLT counts after apheresis with the Spectra (p < 0.01). The Amicus had a longer running time than the Spectra for processing similar volumes (p < 0.005).

CONCLUSION

The automated program of the Amicus may be better than that of the Spectra for collecting MNCs and CD34+ PBPCs and avoiding apheresis-induced thrombocytopenia.

Evaluation of the COM.TEC cell separator in predicting the yield of harvested CD34+ cells

BACKGROUND

This multicenter study was performed with the intention to evaluate the exactness of the predicted CD34+ cell yield calculated by two leukapheresis programs of the cell separator COM.TEC upon the number of donor's circulating CD34+ cells and the blood volume processed.

STUDY DESIGN AND METHODS

Patients and healthy donors (n = 166) received mobilization by chemotherapy and/or granulocyte colony-stimulating factor and underwent CD34+ cell harvest by the leukapheresis programs MNC or RV-PBSC (n = 203).

RESULTS

CD34+ cells were collected by 112 harvests on MNC and by 91 collections on RV-PBSC. The median collection efficiency of CD34+ cells was significantly better for the program MNC than for RV-PBSC (p < 0.001): 67% (31-109) vs. 42% (19-100). The collected CD34+ cell yield was in median more exactly by MNC than by RV-PBSC (p < 0.001): 85% (31-176) vs. 59% (22-110) of the predicted value. Concentrates obtained by RV-PBSC showed in median significantly higher percentages of mononuclear cells (p < 0.001) and CD34+ cells (p < 0.001), 86% (43-99) vs. 56% (25-95) and 1.2% (0.2-14.3) vs. 0.4% (0.1-6.0), and had lower contaminations by erythrocytes (p < 0.001) and platelets (p < 0.001), 13 mL (4-48) vs. 25 mL (5-60) and 1.9 x 1011 vs. 3.1 x 1011, than those harvested by MNC.

CONCLUSION

The significantly better collection efficiency of CD34+ cells and the more exact prediction of the harvested CD34+ cell yield make the leukapheresis program MNC a safe and efficient procedure. However, concentrates collected by RV-PBSC are of a better cellular quality with a significantly higher percentage of mononuclear and CD34+ cells and a lower contamination by erythrocytes and platelets.

Comparison of the Fenwal Amicus and Fresenius Com.Tec cell separators for autologous peripheral blood progenitor cell collection

Peripheral blood progenitor cells (PBPC) are commonly used as a stem cell source for autologous transplantation. This study was undertaken to evaluate blood cell separators with respect to separation results and content of the harvest. Forty autologous PBPC collections in patients with hematological malignancies were performed with either the Amicus or the COM.TEC cell separators. The median product volume was lower with the Amicus compared to the COM.TEC (125 mL vs. 300 mL; p < 0.001). There was no statistically significant difference in the median number of CD34+ cell/kg in product between the Amicus and the COM.TEC (3.0 x 10(6) vs. 4.1 x 10(6); p = 0.129). There was a statistically higher mean volume of ACD used in collections on the Amicus compared to the COM.TEC (1040 +/- 241 mL vs. 868 +/- 176 mL; p = 0.019). There was a statistical difference in platelet (PLT) contamination of the products between the Amicus and the COM.TEC (0.3 x 10(11) vs. 1.1 x 10(11); p < 0.001). The median % decrease in PB PLT count was statistically higher in the COM.TEC compared to the Amicus instruments (18.5% vs. 9.5%; p = 0.028). In conclusion, both instruments collected PBPCs efficiently. However, Amicus has the advantage of lower PLT contamination in the product, and less decrease in PB platelet count with lower product volume in autologous setting.

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.

Whole-blood leukodepletion filters as a source of CD34+ 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.

Mobilization and collection of peripheral blood progenitor cells for transplantation

Bone marrow transplantation gradually expanded as a treatment modality for various malignant and non malignant disease conditions. Since the discoveries of the potential of Peripheral Blood Progenitor Cells (PBPC) in the hematopoietic reconstitution mid 1980s and early 1990s PBPC gradually replaced bone marrow as the preferred source of stem cells. The introduction of hematopoietic cytokines that can mobilize large number of progenitors into circulation accelerated PBPC usage. Technological advancements in the apheresis instrumentation greatly helped in the conversion from marrow to PBPC. PBPC collection is less painful, less expensive and transplant with PBPC results in faster hematological recovery than with marrow. Almost all of the autologous transplants are currently performed with PBPC and a similar trend is seen with the allogeneic transplants. The progenitor cell mobilization regimen for autologous patients can be cytokines alone or cytokines combined with chemotherapy. In the majority of the patients the required minimal cell dose of 2.5-5.0 x 10(6)/kg CD34+ cells can be collected in one or two apheresis collections. A few of autologous transplant patients who mobilize poorly require several collections. Allogeneic donors are generally mobilized with daily subcutaneous injections of G-CSF 10 microg/kg for 5 days. The PBPC are collected in one or two apheresis procedures. The side effects of G-CSF are generally mild to moderate; however rare serious reactions including rupture of the spleen have been reported. The collection of PBPC in pediatric patients poses additional challenges yet an adequate dose of cells can be collected with the available apheresis instrumentation. The apheresis collection procedures are safe with no serious adverse consequences. Future scientific advancements may expand the use of PBPC for other clinical application in addition to the current use for hematological reconstitution.

Safe And Efficient Collection of Cytokine-Mobilized Peripheral Blood Cells From Cynomolgus Monkeys (Macaca fascicularis) with Human Newborn-Equivalent Body Weights

Hematopoietic stem cells in bone marrow can be mobilized into peripheral blood by cytokine administration. Cytokine-mobilized peripheral blood stem cells are of great use in clinical applications. We previously established a modified procedure for the collection of cytokine-mobilized peripheral blood cells from rhesus monkeys (Macaca mulata) using a commercially available apparatus originally developed for human subjects. In this study, we examined the efficacy and safety of this method with even smaller macaques, cynomolgus monkeys (Macaca fascicularis), which are equivalent to human newborns in body weight (mean = 3.3 kg). Using the manufacturer's unmodified protocol (n=6), one monkey died of cardiac failure and three developed severe anemia. In contrast, using our modified procedure (n=6), no such complication was observed in any animal. In addition, the harvested nuclear cell, mononuclear cell and CD34(+) cell counts were significantly higher with the modified method. The modified method should allow safe and efficient collection of cytokine-mobilized peripheral blood cells from non-human primates as small as human newborns in a non-invasive manner.

Apheresis techniques for collection of peripheral blood progenitor cells

The combination of effective mobilisation protocols and efficient use of apheresis machines has caused peripheral blood progenitor cells (PBPC) transplantation to grow rapidly. The development of apheresis technology has improved over the years. Today PBSC procedures have changed towards systems to minimise operator interaction and to reduce the collection of undesired cells such as polymorphonuclear cells and platelets using functionally closed, sterile environments for PBSC collection in keeping with Good Manufacturing Practice guidelines. Blood cell separators with continuous flow technique allow the processing of more blood than intermittent flow devices resulting in higher PBSC yields. Large volume leukapheresis with the processing of 3-4-fold donor's/patient's blood volume can increase the number of collected progenitor cells. Therefore, intermittent flow cell separators are indicated if only single vein access is available. Anticoagulant induced hypocalcaemia is an often observed side effect in long lasting PBPC harvesting and monitoring of electrolytes should be performed especially at the end of the apheresis procedure to supplement low levels of potassium, calcium or magnesium. Refinement and improvement of collection techniques continue to add to the armamentarium of current approaches for cancer and non-malignant conditions and will enable future strategies.

Recommendations for optimized settings of the Amicus Crescendo cell separator for the collection of CD34+ progenitor cells

BACKGROUND

CD34+ PBPCs for autologous transplantation purposes are collected by leukapheresis procedures on automated cell separators. In this study, the influence of different parameters on collection efficiency (CE) of the Amicus Crescendo cell separator (Baxter) was investigated.

STUDY DESIGN AND METHODS

A total of 146 PBPC collections with Amicus cell separators were performed in 56 patients with either settings recommended by the manufacturer or modified settings to identify variables that have a significant and important impact on CE.

RESULTS

By use of a standard setting with a cycle volume of 1400 mL, CE significantly decreases when patients' preapheresis peripheral blood WBC counts are between 25,000 and 35,000 per micro L. CE can be improved if cycle volume is reduced to 1000 mL. If WBC concentrations exceed 55,000 per micro L before apheresis, CE also significantly decreases despite of reduced cycle volume. Additionally, high flow rates greater than 60 mL per minute significantly reduce CE.

CONCLUSION

Parameters influencing the outcome of CD34+ PBPC collections were identified, such as patients' WBC count, cycle volume, and whole blood flow rate. An optimized adjustment of these variables will further increase the CE of the device.