Recovery Of Mononuclear Cells Research Articles

Cord blood banking: volume reduction of cord blood units using a semi-automated closed system.

Clinical evidence indicates that placental/umbilical cord blood (CB) is an alternative source of haematopoietic stem cells for bone marrow reconstitution. To establish a CB bank large panels of frozen, HLA-typed CB units need to be stored. Cryopreserved, unprocessed CB units require vast storage space. This study describes a method, using the Optipress II Automated Blood Component Extractor (Opti II) from Baxter Healthcare Corporation, to reduce the volume of the CB collection, preserving the quantity and quality of the progenitor cells, in a closed system. The CB collection was transferred to a triple bag system, centrifuged to produce a buffy coat layer and processed using a standard Opti II protocol to separate the whole blood into three components: plasma, buffy coat and buffy coat-depleted red cell concentrate. The buffy coat volume was standardised to 25 ml; mean reduced volume of 24.5 ml (s.d. 1.5 ml) with 53% red cell depletion. Good recovery of cells was observed: 92%, 98%, 96% and 106% recovery of nucleated, mononuclear, CD34+ and total colony-forming cells, respectively. Using this method for processing CB units reduces storage requirement by two-thirds but preserves the quantity and quality of the progenitor cells.

Umbilical cord blood banking for unrelated transplantation: Evaluation of cell separation and storage methods

Cost-efficient umbilical cord blood (UCB) banking requires well-standardized methods of volume reduction and storage. To compare UCB fractionation using a technique of hydroxyethyl starch (HES) sedimentation with the Ficoll (double) and Percoll methods, 50 whole units was allocated randomly to each procedure. HES resulted in a significantly better recovery of mononuclear cells (87.5%), granulocyte/macrophage colony-forming units (CFU-GM) (88.4%), and CD34 + cells (87.4%) and lesser volume reduction (85.5%). HES was the least laborious, time consuming, and expensive of the three procedures, costing 3.4- and 4.4-fold less than the Ficoll and Percoll methods, respectively. Five units processed by each method was frozen in 4.5-mL cryotubes under optimal conditions. After thawing, the greatest degree of recovery of viable nucleated cells and number of CFU-GM per unit were obtained using the HES procedure. Using 4.5-mL cryotubes, the calculated number of units that could be stored in 600-L containers was 3.8- and 2.2-fold higher for Ficoll- and Percoll-separated than for HES-separated units, respectively. Nevertheless, the higher direct costs of the density gradient separation procedures outweighed their lower storage cost. For long-term cryopreservation, we assessed the freezing of HES-processed units in 50-mL cryobags and their specifically designed canisters. We found cell recoveries similar to those obtained with cryotubes, but storage capacity was decreased. Special racks designed for these canisters resulted in a 5-fold increase over the number of units stored in standard cryobags. This system also is feasible for Percoll- and Ficoll-separated units, resulting in comparable storage costs for the three separation methods. We conclude that this HES procedure and the 50-mL cryobags constitute a cost-efficient system for large-scale UCB banking.

Development of an infusible-grade solution for non-cryopreserved hematopoietic cell storage

Various tissue culture medium formulations currently are used to transport, store and process stem and progenitor cells for transplantation, although these solutions are not manufactured for clinical use. We have developed an infusible-grade solution, STM-Sav, for short-term liquid cell storage and tested its ability to maintain viable functional hematopoietic cells, compared with commonly-used tissue culture solutions. G-CSF-stimulated normal-donor PBPC were stored in alpha-MEM, IMDM, RPMI-1640, AIM 5, X-VIVO 10, PlasmaLyte A and STM-Sav, in gas-permeable Cryocyte bags, at ambient temperature and 4 degrees C. The percentage of viable cells, percent recovery of viable mononuclear cells (MNC), percentage of CD34+ cells, CFU-GM frequency and solution pH were determined for each solution, at time points ranging from 0 to 72 h. Cells were slightly better maintained at 4 degrees C than at ambient temperature. No solution was superior to any other overall, although PlasmaLyte A was significantly inferior to all other solutions at preserving viable MNC. STM-Sav consistently maintained viable, functional cells as well as, or better than in-vitro-use-only culture media, or PlasmaLyte A. Cells could be stored in STM-Sav for at least 24 h at 4 degrees C or ambient temperature, with recovery of approximately 90% of initial viable MNC, unchanged percentage CD34+ cells and stable solution pH.

Viability and recovery of peripheral blood mononuclear cells cryopreserved for up to 12 years in a multicenter study.

The Multicenter AIDS Cohort Study (MACS), an ongoing prospective study of the natural history of human immunodeficiency virus (HIV), has stored biologic specimens, including peripheral blood mononuclear cells (PBMC), from 5,622 participants for up to 12 years. The purpose of the present analysis was to evaluate the quality of the PBMC in the MACS repository in order to test the validity and feasibility of nested retrospective studies and to guide the planning of future repositories. PBMC were collected from MACS participants at four centers at 6-month intervals from 1984 to 1995, cryopreserved, and transported to a central repository for storage. A total of 596 of these specimens were subsequently tested for viability and used to evaluate cell function, to conduct immunophenotype analysis, or to isolate HIV. Simple linear regression models were applied to evaluate trends in recovery and viability over time and by center. Results indicated that from a nominal 10(7) cells cryopreserved per vial at all four centers, the median number of viable cells recovered was at least 5 x 10(6) (50% of the number stored) and the median viability was at least 90%. Results suggested that cryopreserved cells can be stored for at least 12 years with no general tendency toward cell loss over time. Furthermore, there were no statistically significant changes in the percent cell viability according to the length of time frozen, regardless of HIV serostatus or the level of CD4(+) lymphocytes. Storing 10(7) PBMC per vial yields sufficient viable cells for phenotypic and/or functional analysis. Results from the MACS provide the basis for the planning of future repositories for use by investigators with similar research goals.

Long-term storage at -80 degrees C of hematopoietic progenitor cells with 5-percent dimethyl sulfoxide as the sole cryoprotectant.

Hematopoietic progenitor cells (HPCs) can be cryopreserved and stored below -120 degrees C in liquid nitrogen or at -80 degrees C in mechanical freezers. The feasibility of long-term storage of HPCs at -80 degrees C was investigated. The studies included a comparison of 5- and 10-percent dimethyl sulfoxide (DMSO) as cryoprotectant at various lengths of storage time. Mononuclear cell (MNC) recovery and viability and colony-forming unit-granulocyte-macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E) recovery assays were performed. The peripheral blood HPCs of 24 consecutive patients included in the program of autologous transplantation were studied. The MNC viability decreased progressively with the length of time from cryopreservation, reaching 32 percent after 31 months of storage. The recovery rates of CFU-GM and BFU-E also decreased progressively with the duration of frozen storage, to 50 and 43.5 percent, respectively, after 12 months and to 0 percent (both) after 24 months. At 6 months of storage, MNC viability was 80 percent, and CFU-GM and BFU-E recovery was 63.5 and 80.5 percent, respectively. There were no differences between MNCs cryopreserved with 5- or 10-percent DMSO in terms of cell viability. There were no differences between CFU-GM recovery or BFU-E recovery from HPCs cryopreserved in 5- or 10-percent DMSO. Patients given HPCs stored in these conditions for periods ranging between 123 and 202 days showed a complete and rapid hematologic recovery. HPCs can be cryopreserved at -80 degrees C with 5-percent DMSO and stored at -80 degrees C no longer than 6 months. A 5-percent DMSO concentration is comparable to a with 10-percent concentration in terms of recovery and MNC viability.

Quantitative immunophenotypic characterization, cryopreservation, and enrichment of second- and third-trimester human fetal cord blood hematopoietic stem cells (progenitor cells)

Objective: The aims of this study were (1) to assess the hematopoietic stem cell (progenitor cell) contents of umbilical cord blood samples from second-trimester and early-third-trimester fetuses versus term fetuses and (2) to determine the feasibility of cryopreservation and enrichment of cord blood from fetuses of different gestational ages. Study Design: Cord blood between 13 and 42 weeks’ gestation (n = 31) was sampled after delivery or fetal expulsion. Fluorescence-activated cell sorting was used to measure CD34 + and CD34 + CD38 – cell numbers. Samples were cryopreserved with 10% dimethylsulfoxide, and CD34 + enrichment was performed by magnetically activated cell sorting with the MiniMACS system (Miltenyi Biotech, Bergisch Gladbach, Germany). Kruskal-Wallis analysis of variance and the Mann-Whitney U test were used for analysis of data. Results: CD34 + and CD34 + CD38 – cell contents were significantly higher in second- and early third-trimester fetuses than in term fetuses (CD34 + 2.57% ± 0.38%, 1.48% ± 0.31%, and 0.7% ± 0.13%, respectively, P = .0067; CD34 + CD38 – 0.72% ± 0.26%, 0.18% ± 0.05%, and 0.06% ± 0.02%, respectively, P = .0132). Mononuclear cell recovery, viability, and CD34 + cell purity after cryopreservation and enrichment were similar among different gestational ages. Conclusion: Cord blood stem cell content decreases significantly from the second trimester to term. Cryopreservation and enrichment of these cells from earlier gestational ages is feasible. This might be especially useful for allogeneic stem cell transplantation and for in utero gene therapy. (Am J Obstet Gynecol 1998;179:1228-33.)

Preservation of immunological and colony-forming capacities of long-term (15 years) cryopreserved cord blood cells.

Cryopreserved cord blood may be stored for decades before being used for allogeneic stem cell transplantation. Little is known about the effect of long-term cryopreservation in liquid nitrogen on the viability and function of cord blood cells. We examined the recovery, viability, clonogenic capacity, and T-cell reactivity to HLA alloantigens of cord blood samples cryopreserved up to 15 years. Progenitor cell recoveries were studied by (colony-forming unit-granulocyte-macrophage) clonogenic assays from 18 cord blood samples short-term frozen for 2-8 weeks and from 8 samples cryopreserved for 15 years. Proliferative and cytotoxic responses against HLA antigens of thawed cord blood mononuclear cells after short-term or long-term cryopreservation were tested in standard mixed lymphocyte cultures and cell-mediated lympholysis assays. After thawing, the mononuclear cell recovery from long-term frozen cord blood low-density fractions averaged 80% (range, 64% to 92%). The presented data show that long-term frozen cord blood cells keep their clonogenic potential. No damaging effect was seen on the proliferative and cytotoxic capacities of long-term frozen cord blood T cells. The results support the possibility of long-term storage of progenitor cells from umbilical cord blood for future bone marrow reconstitution.

Efficacy and kinetics of bone marrow processing and enrichment of haematopoietic progenitor cells (HPC) by a large-volume apheresis procedure.

We investigated the efficacy of bone marrow (BM) processing by an automated large-volume apheresis procedure (6 x original BM volume) in 10 paediatric and adult patients undergoing BM harvesting before myeloablative therapy. Volume-dependent kinetics during apheresis were analyzed by sequential collection of processed cells into a six-fold collection bag system with consecutive analysis of the single bags. BM processing resulted in an 83.3% (+/- 21) recovery of mononuclear cells (MNC), a 97.9% (+/- 1.1) reduction of erythrocytes (RBC) and a 87.7% (+/- 2.9) volume reduction. To determine volume-dependent kinetics of haematopoietic progenitor cell (HPC) enrichment during apheresis, leukocytes (WBC), mononuclear cells (MNC), CD34 cells and colony-forming cells (CFU-GM) were serially quantitated in subsequent collection bags. Large-volume BM processing significantly enhanced absolute yields of CD34+ cells (mean: 4.01 (+/- 2.81) x 10(6)/kg bw) and CFU-GM (mean: 1.92 (+/- 1.47) x 10(4)/kg bw) compared with the standard procedure (3 x BM volume) by 26.9% (+/- 10.9) and 27.2% (+/- 11.6), respectively. We concluded that large-volume apheresis for BM processing is an efficient technique significantly improving the yields of haematopoietic progenitor cells (HPC) without any relevant changes in the purity of the final product. Moreover, sequential collection and analysis of HPC represents a good model to investigate the volume-dependent kinetics and efficacy of BM processing.

Recovery of Patient Peripheral Blood Mononuclear Cells after Treatment with Protease Inhibitor in Post-transfusion Graft-versus-host Disease.

Post-transfusion graft-versus-host disease (PT-GVHD) is a fatal adverse effect of blood transfusion.1)-3) The mortality rate is said to be 99% or higher.4) In spite of the seriousness of the disease, no definitively effective drug for curing patients of it has been identified. Recently, however, we reported on the potential usefulness of a protease inhibitor, nafamostat mesilate (NM), for treatment of PT-GVHD.5), 6) This potential usefulness of NM was suggested by the results in vitro experiments in which possible PT-GVHD effector cytotoxic T cell (CTL) clones and tumor necrosis factor β (TNF β) producing T cell clones established by us were used.7), 10) NM inhibited the cytotoxicity of the CTL clones and TNF β production by the TNF β producing clones.6) Based on these results, NM was administered to two patients with PT-GVHD. NM administration resulted in marked recovery of the patient peripheral blood mononuclear cell (PBMC) detected by microsatellite DNA polymorphism analysis distinguishable between donor and patient PBMCs. This is the first report of the marked recovery of PT-GVHD patient PBMC from very low ones which were replaced almost all with donor PBMCs. Moreover, NM administration was associated with body temperature normalization, disappearance of a body rash, liver function improvement and an unusual long survival time after onset of PT- GVHD in both cases. NM is potentially useful drug for treatment of PT-GVHD.

Interleukin-12 administered in vivo decreases human NK cell cytotoxicity and antibody-dependent cellular cytotoxicity to human immunodeficiency virus-infected cells.

Persons infected with human immunodeficiency virus (HIV) have cellular cytotoxicity defects. Interleukin (IL)-12 is a potent stimulator of cytotoxicity. Fifteen HIV-infected patients were studied in a phase 1, single-dose escalation trial of human recombinant IL-12. One day after subjects received an IL-12 dose of 300 or 1000 ng/kg, they had a reduction in absolute lymphocyte count and peripheral blood mononuclear cell recovery. In evaluable patients 24 h after IL-12 administration, there was a 31% reduction overall in NK cell cytotoxicity (NKC) to HIV-infected cells at all doses and a 52% reduction in antibody-dependent cellular cytotoxicity (ADCC) at doses of 300 and 1000 ng/kg. In vitro incubation of patients' cells with IL-12 (before IL-12 administration) for 24 h increased NKC but had no effect on ADCC. The paradoxic acute reduction in cell number and cytotoxicity in vivo may be due to NK cell trafficking or regulatory cytokine mechanisms not apparent in vitro.

Analysis for recovery and loss of mononuclear cells and colony-forming units granulocyte-macrophage during ex vivo processing of autologous bone marrow.

During ex vivo processing of autologous bone marrow (BM) substantial loss of stem and progenitor cells should be avoided to achieve rapid and sustained hematopoietic reconstitution after high-dose radio-/chemotherapy. We processed 25 autologous BM grafts with the Fresenius AS104 cell separator for cryopreservation and we determined recoveries for mononuclear cells (MNC) and colonyforming units granulocyte-macrophage (CFU-GM) in the BM concentrates. To identify cell loss in BM fractions not cryopreserved, we investigated the MNC and CFU-GM content of BM fat and BM blood. MNC and CFU-GM recovery yielded a mean ( +/- SEM) of 42 +/- 12 and 54 +/- 20% in the BM concentrate. BM fat showed a mean loss of 7 +/- 5% for MNC and 4 +/- 3% for CFU-GM, BM blood 30 +/- 12% for MNC and 13 +/- 13% for CFU-GM, respectively. CFU-GM recovery was significantly higher in the BM concentrate of patients with hematologic malignancy (HM) compared with patients suffering from germ cell cancer (GCC): 66 +/- 21 vs. 43 +/- 12% (p < 0.02). Seventeen patients (7 GCC, 10 HM) underwent high-dose chemotherapy or radio-/chemotherapy and were autografted with 0.8 +/- 0.2 x 10(8) MNC/kg and 3.7 +/- 2.0 x 10(4) CFU-GM/kg. All patients achieved engraftment with neutrophils > 0.5 x 10(9)/l at a mean of 14 +/- 6 days. We conclude that: (1) ex vivo processing of autologous BM with a mean of recovery of 42% for MNC and 54% for CFU-GM in the BM concentrate can result in a cell population capable of sustained hematopoietic reconstitution, (2) CFU-GM recovery is significantly higher in patients with HM than in patients with GCC and (3) 37% MNC and 17% CFU-GM represent in fact cell losses recovered from BM fractions not cryopreserved (BM fat, BM blood). Furthermore, it is likely that MNC and CFU-GM not recovered from BM concentrate, BM fat and BM blood are cell losses related to the cell separator.

Analysis for Recovery and Loss of Mononuclear Cells and Colony-Forming Units Granulocyte-Macrophage during ex vivo Processing of Autologous Bone Marrow

Analysis for Recovery and Loss of Mononuclear Cells and Colony-Forming Units Granulocyte-Macrophage during ex vivo Processing of Autologous Bone Marrow

The human HIV/peripheral blood lymphocyte (PBL)-SCID mouse. A modified human PBL-SCID model for the study of HIV pathogenesis and therapy.

PBL from HIV-infected patients were engrafted into CB-17 SCID mice to develop a novel small animal model for the study of HIV pathogenesis and therapy. Engraftment was achieved in 84% of mice, with human Ig (hu-Ig) levels and total human mononuclear cell recovery by peritoneal wash similar to those in control hu-PBL-SCID mice engrafted with uninfected donor cells. The hu-Ig produced by hu-HIV/PBL-SCID mice had broad reactivity against HIV. Virus could be detected in 98% of mice by polymerase chain reaction and/or viral coculture. Viremia was first detected by quantitative polymerase chain reaction on day 7 (approximately 10,000 copies of viral RNA/ml of plasma) and persisted through day 17. Quasispecies analysis of amplified, cloned, proviral DNA of the V3 region of the env gene showed that nucleotide sequences from hu-HIV/PBL-SCID mouse peritoneal wash cells on day 17 were not significantly changed from those derived from donor PBL at the time of injection. Relative to human CD4+ T cell recovery by peritoneal wash in control hu-PBL-SCID mice (CD4 = 19 +/- 2%; n = 40), severe CD4+ lymphocyte depletion (CD4 = 5 +/- 0.5%; n = 59; p < 0.001) was observed in untreated hu-HIV/PBL-SCID mice 18 to 25 days after engraftment. Treatment with 2'-beta-fluoro-2',3'-dideoxyadenosine, a nucleoside analogue, significantly reduced CD4+ T cell depletion (CD4 = 13 +/- 1; n = 59; p < 0.001) and the frequency of virus isolation (70%; p = 0.015) in the hu-HIV/PBL-SCID model. Boosting hu-Ig levels in the mice by injection of purified donor Ig with neutralizing activity did not affect the frequency of CD4+ lymphocyte recovery or virus isolation. The administration of a mAb to TNF had minimal effects. These studies demonstrate that PBL from HIV-infected donors can engraft SCID mice; that HIV can be detected in the spleen, peritoneal wash cells, and blood of these mice; that HIV infection within the model results in rapid CD4+ T cell depletion; and that anti-retroviral therapy is effective in improving CD4+ T cell recovery and reducing the frequency of virus isolation. The hu-HIV/PBL-SCID mouse model thus represents a potentially useful model in which to study HIV pathogenesis and therapy.

Evaluation of the Fresenius cell separator AS 104 for harvesting peripheral blood stem cells in pediatric patients

In a single institution trial we carried out 35 peripheral blood stem cell harvesting procedures in 12 children with advanced malignancies to evaluate the procedure's safety and the collection efficiency of the Fresenius blood cell separator AS 104 in a pediatric population. Despite a significant mean decrease of 21% (± 8%) in systolic blood pressure after starting the procedure, all children tolerated leukapheresis without any adverse reaction. After termination of leukapheresis there was a significant decrease of all determined hematological parameters, as compared with pre-harvest values. The mean mononuclear cell recovery was 64% (± 26%), and in 25 35 (71%) harvesting procedures the minimum progenitor number required for safe autografting could be obtained by one single leukapheresis. We conclude that the Fresenius AS 104 blood cell separator provides a high cell yield and is a safe device for leukapheresis in pediatric patients.

Differential effect of cryopreservation on natural killer cell and lymphokine-activated killer cell activities.

The use of lymphokine-activated killer (LAK) cell therapy in delayed treatment requires the use of cryopreserved effector cells. The purpose of this study was to determine the optimal cryopreservation protocol for the maintenance of cytotoxic activity in mononuclear cells (MNCs). MNCs were cryopreserved with dimethyl sulfoxide or 1,2-propanediol before and after 3 days of culture with recombinant interleukin 2. The effects of cryopreservation on cell recovery, LAK cell and natural killer (NK) cell cytotoxic activities, and surface antigen markers were studied. Recovery of nonactivated MNCs was higher with 1,2-propanediol than with dimethyl sulfoxide (p < 0.05). Cytotoxic activities, measured with a 51Cr release assay, significantly decreased after thawing, on both activated cells (76.3%; range, 35.8-92.2%) and fresh cells (54.6%; range, 17.5-75.4%). A 6-day kinetic test was used to compare the cytotoxic activity of cryopreserved and fresh cells. The results showed different patterns for NK cells (cryopreserved cells had lower levels of activity than fresh cells) and LAK cells (cryopreserved cells had higher levels of activity than fresh cells). Phenotype changes of effector cells in culture, with and without cryopreservation, were monitored by flow cytometry using monoclonal antibodies. These results were compared with changes in the cytotoxicity of cells with and without cryopreservation. After thawing, there was a decrease in MNCs expressing CD14 and CD56. Recovery of the CD56 marker correlates with increased cytotoxic activity. Despite some loss of NK cell activity, it is concluded that MNCs may be successfully cryopreserved before their use in immunotherapeutic treatment.

Progenitor Cells Purging: Negative Selection

Disease relapse after autologous bone marrow transplantation (ABMT) may arise from residual tumor in the recipient and/or from cancer cells that are reinfused. The aim of purging by negative selection is to remove tumor cells from the marrow without adversely affecting the engraftment potential of the normal cell. We report the results of a study on fifty-six patients (pts) with non Hodgkin's lymphoma or acute leukemia submitted to ABMT after immunomagnetobead (IMB) purging (11 pts), Maphosphamide purging (31 pts) and no purging (14 pts). The IBM procedure involved one incubation of 3 monoclonal antibodies (CD10, CD19 and CD22) and two incubations with magnetic beads (Dynabeads M-450). The median recovery of mononuclear cells and CFU-GM was 40% and 45% after IMB purging and 84% and 5% after Maphosphamide purging respectively. The rate of leukocyte, neutrophils and platelets recovery following ABMT was similar in the three groups of pts, although platelet recovery was slow in patients received graft purged with Maphosphamide. Our study confirms the clinical feasibility of the IMB procedure, but only randomized studies will be able to definitely address the question of the clinical utility of purging.

Barrier Blood Cell Separation Methods Used With Healthy and HIV-Positive Individuals

The ACCUSPIN (Sigma Diagnostics) and the LeucoPREP (Becton Dickinson) barrier methods for mononuclear cell separation were analyzed using density gradient centrifugation. Peripheral blood samples from healthy individuals and from those who tested positive for human immunodeficiency virus (HIV) were processed in parallel using both techniques and evaluated for total and percentage of mononuclear cell recovery. The ACCUSPIN method recovered more cells than the LeucoPREP method in 18 of 19 samples from healthy individuals. Specimens isolated with ACCUSPIN tubes also yielded 25% to 40% more cells than those isolated with LeucoPREP tubes. Similar results were obtained with blood samples from patients who tested HIV-positive.

Effective concentration of bone marrow mononuclear cells using density gradient separation within an automated cell separator

An effective method for concentrating bone marrow is described. Concentration was achieved using an intermittent flow cell separator. Elimination of mature haemopoietic cells was enhanced by the addition of a density separation medium (Ficoll-metrizoate) which was then removed by washing. All procedures were undertaken using the cell separator, this allowed for standardization of procedure and less manipulation which is associated with enhanced mononuclear cell recovery and less risk of microbial contamination. Mature granulocytes were depleted by 86.8% and red cells by 97.7% whilst mononuclear cells showed a 49% recovery. Marrows processed in this way and subsequently purged and/or cyropreserved were shown to successfully engraft when reinfused.

血液センターにおける造血幹細胞の調製および凍結保存について

We concentrated mononuclear cells (MNCs) containing hematopoietic stem cell from bone marrow (BM) or peripheral blood (PB) of patients and MNCs fraction were cryopreserved in cryoprotectant solution (final concentration: 6% hydroxyethyl starch, 5% dimethyl sulfoxide and 4% human serum albumin) without controlled-rate freezing. In preparation of bone marrow MNCs were concentrated by density gradient centrifugation using the COBE 2991, the recovery of MNCs and granulocytemacrophage colony forming unit (CFU-GM) were 56% and 83%, respectively, of the original BM. On the other hand, in preparation of peripheral MNCs were concentrated by low speed centrifugation of lymphocyte fraction collected using the COBE spectra, the recovery of MNCs and CFU-GM were 89% and 90%, respectively. After thawing of both cryopreserved preparations, the recovery of CFU-GM were 58% of original BM and 68% of original PB fraction. These results indicate that the techniques for the separation and storage of blood components in blood center are applicable for the preparation and storage of hematopoietic stem cells from BM and PB.

Effects of L‐leucyl‐L‐leucine methyl ester on human marrow and protection of progenitor cells by IL‐1

In murine models, L-leucyl-L-leucine methyl ester (LLME) is effective as an ex vivo purging agent for the prevention of graft-versus-host disease. However, reduction of progenitor cells by LLME raises concerns about the engraftment potential of LLME-treated marrow. Therefore, the effects of LLME on human marrow were investigated. Concentrations of LLME from 0.005 mM to 5 mM were used to examine the effects of LLME on marrow cells. Concentrations of LLME less than or equal to 0.05 mM had no effect on recovery of nucleated marrow cells, mononuclear cells (MNC), myeloid cells or monocytes. At 0.5 mM, nucleated marrow cell recovery was 25%, and MNC recovery was 93%. As determined by cytochemical stains, 0.5 mM LLME eliminated myeloid cells and monocytes. At 0.005 mM, LLME had little effect on marrow progenitor cells; progenitor cell recovery with 0.05 mM LLME was 35% for granulocyte-macrophage colony forming units (CFU-GM) and 23% for erythroid burst forming units (BFU-E) (p less than 0.05 compared to 0.005 mM). At higher LLME concentrations, recoveries of both CFU-GM and BFU-E were less than 1%. To determine if earlier hematopoietic cells remained after treatment with LLME, progenitor cell experiments were repeated with 0.5 mM LLME using recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) or recombinant human interleukin 3 (rhIL-3) plus or minus recombinant human mast cell growth factor (rhMGF) as sources of colony-stimulating activity. In this system, both IL-3 and GM-CSF induced rare progenitor cells (less than 6/5 x 10(4) cells plated).(ABSTRACT TRUNCATED AT 250 WORDS)