GCSF-mobilized Peripheral Blood Stem Cells Research Articles

Ex Vivo Culture with Albumin Greatly Increases the Immunosuppressive Subset of T Lymphocytes

Emerging studies suggest that the expression of co-inhibitory receptors such as PD1, TIM3, TIGIT, and LAG3 on the T cell surface is important in regulating T cell response. However, the low number of cells expressing such co-inhibitory receptors in peripheral blood severely limits their clinical potential in treating GVHD. In this study, we introduce a novel method to culture and obtain a high number of CD3+PD1+TIM3+ lymphocytes that also exert strong immunosuppression. We demonstrate that culturing CD3+ cells isolated from G-CSF mobilized peripheral blood stem cells (G-PBSCs) with human serum albumin (HSA) greatly increases the number of immunosuppressive CD3+ cells. Also, we confirm that the CD3+PD1+TIM3+ lymphocytes are the most potent subset of the CD3+ cells that induce immunosuppression and inhibit T cell proliferation. Methods. The donors were subcutaneously injected with G-CSF (10μg/kg) for five days. G-PBSCs were collected from the donors using a COBE spectra cell separator, and CD3+ cells were isolated by positive selection by magnetic-activated cell sorting (MACS) using CD3 Dynabeads™. Isolated CD3+ cells were cultured with 5% HSA for 4 days (1x105 cells/mL). PD1, TIM3, LAG3, and TIGIT expressions were analyzed using flow cytometry (FACS). CD3+, CD3+PD1+, and CD3+PD1+TIM3+ lymphocytes were sorted and cultured with irradiated allo-MNCs for three days (Mixed Lymphocyte Reaction; MLR). 5,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) was used as an intracellular fluorescent dye in MLR (CFSE-MLR) to measure T cell proliferation. Results. We discovered that treating G-PBSC cells with 5% HSA resulted in a dramatic increase in the number of immunosuppressive lymphocytes after the HSA treatment. In untreated G-PBSCs, there were very low numbers of CD3+PD1+TIM3+, CD3+PD1+LAG3+, and CD3+PD1+TIGIT+ lymphocytes (0.9±0.3x103, 0.1±0.1x103, and 0.3±0.2x103, respectively). In G-PBSCs, the HSA treatment markedly increased the cell numbers (47.6±1.9x103, 7.8±3.0x103, and 0.7±0.3x103, respectively) while resulting in a mild increase in the total number of CD3+ cells (1.2-fold increase, 1x105 to 1.2±0.4x105). Our data also demonstrated significant percent changes in subpopulations of CD3+ lymphocytes. In untreated G-PBSCs, very low percentages of cells were CD3+PD1+TIM3+, CD3+PD1+LAG3+, and CD3+PD1+TIGIT+ (9.0±3.1%, 1.2±0.1% and 3.2±2.8% in G-PBSC, respectively). After the HSA treatment, the percentages of the immunosuppressive lymphocytes in G-PBSCs markedly increased to 39.7±9.1%, 6.5±1.3%, and 0.6±0.4%, respectively. In particular, CD3+PD1+TIM3+ lymphocytes demonstrated the greatest increase in the cell number and the percentage after the HSA treatment, increasing by ~52 fold. Next, we tested whether the HSA-treatment induced proliferation of immunosuppressive T cells translated into increased immunosuppression. To do this, we used CSFE-MLR, co-cultured the CD3+ G-PBSCs with allo-MNCs, and analyzed the number of unstimulated T cells. The HSA-treated CD3+ G-PBSCs significantly increased the levels of unstimulated T cells compared to the untreated G-PBSCs (% of unstimulated T cells in untreated cells vs. in HSA-treated cells; 0.5±0.1 vs. 15.4±11.7), indicating that the HSA treatment increased CD3+ cell-mediated immunosuppression. Lastly, we tested the immunosuppressive effects of CD3+PD1+ and CD3+PD1-lymphocytes in HSA-treated CD3+ G-PBSCs. Both CD3+PD1+ and CD3+PD1+TIM3+ lymphocytes demonstrated significantly enhanced levels of immunosuppression compared to CD3+PD1-lymphocytes and CD3+PD1+TIM3- lymphocytes, respectively (% of unstimulated T cells in CD3+PD1+ vs. in CD3+PD1-lymphocytes, 27.9±5.5 vs. 4.3±7.5, and % of unstimulated T cells in CD3+PD1+TIM3+ vs. in CD3+PD1+TIM3- lymphocytes, 46.1±5.5 vs. 17.4±7.4). Collectively, these data suggest that PD1 and TIM3 are key markers in the HSA-dependent increase in immunosuppression. Conclusion. The ex vivo culture of CD3+ G-PBSCs with HSA markedly increases both the number and the effect of immunosuppressive CD3+ lymphocytes. Our analysis also indicates that the increased immunosuppression is likely due to the proliferation of CD3+PD1+TIM3+ lymphocytes. Taken together, our data suggest that the ex vivo HSA treatment of CD3+ G-PBSCs shows promising therapeutic potential for treating patients with GVHD.

Ex Vivo IL-2 Treatment Increases the Immunosuppressive Subset of T Lymphocytes to Suppress Allo-Immune Response

T lymphocytes are critical players in graft-versus-host disease (GVHD); however, their specific roles and mechanisms in GVHD have not been clearly defined. Co-inhibitory receptors including PD1, TIM3, TIGIT, and LAG3 play a key role in regulating T cell responses and maintaining immune homeostasis. TIM3 expression on lymphocytes was identified to induce immune tolerance in a mouse GVHD model; in addition, PD1 +TIM3 + double-positive T cells displayed more potent immunosuppression compared to PD1 + T cells. However, despite the strong immunosuppression exerted by PD1 +TIM3 + double-positive T cells, their clinical potential is greatly limited by their low cell number in peripheral blood. In this study, we introduce a novel method to isolate CD3 + cells from G-CSF mobilized peripheral blood stem cells (G-PBSCs), and culture CD3 +PD1 +TIM3 + lymphocytes to treat GVHD.Methods. The donors were subcutaneously injected with G-CSF (10μg/kg) for five days. G-PBSCs were collected from the donors using a COBE spectra cell separator. Then, the highly purified CD3 + cells were isolated by positive selection with magnetic-activated cell sorting (MACS) from G-PBSCs using CD3 Dynabeads™. Isolated CD3 + cells were cultured with a low concentration of IL-2 (50U/mL), and PD1, TIM3, LAG3, and TIGIT expressions were assessed using flow cytometry (FACS). CD3 +PD1 +TIM3 +, CD3 +PD1 +TIM3 +LAG3 +TIGIT - and CD3 +PD1 +TIM3 +LAG3 +TIGIT +cells are sorted and cultured with irradiated allo-MNCs for 4 days (Mixed Lymphocyte Reaction; MLR). We used 5,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) as an intracellular fluorescent dye in MLR (CFSE-MLR) to measure of T cells proliferation.Results. In normal, untreated G-PBSCs, very low percentages of cells are CD3 +PD1 +TIM3 +, CD3 +PD1 +LAG3 + and CD3 +PD1 +TIGIT + (0.6±0.4, 0.3±0.2 and 1.3±0.5% in G-PBSC, respectively). However, after treating G-PBSC cells with a low concentration of IL-2 (50 U/mL), we discovered the percentages of CD3 +PD1 +TIM3 +, CD3 +PD1 +LAG3 +, and CD3 +PD1 +TIGT + lymphocytes in G-PBSCs markedly increased by 19.6±5.9, 18.5±4.3, 17.7±6.5%, respectively. Of note, there was a very small change (~1.2 fold increase) in the total number of CD3 + lymphocytes, which indicates that the low dose IL-2 therapy alters subpopulations of T lymphocytes, rather than increasing the proliferation rate. Next, we tested the immunosuppressive capacity of the cultured CD3 +PD1 +TIM3 +cells. To do this, we used CSFE-MLR to measure T cell proliferation. CD3 +PD1 +TIM3 + lymphocytes were depleted in CD3 + G-PBSCs by flow cytometry-based cell sorting. Then we cultured the CD3 + G-PBSCs with allo-MNCs and discovered that the CD3 + G-PBSCs that lacked CD3 +PD1 +TIM3 + lymphocytes demonstrated a significantly increased level of T-cell proliferation compared to CD3 + G-PBSCs, and thereby confirming the immunosuppressive function of CD3 +PD1 +TIM3 + lymphocytes in inhibiting T cell proliferation (% of unstimulated T cells in CD3 + G-PBSCs vs. in CD3 +PD1 +TIM3 + depleted G-PBSC CD3 + cells; 33.5±7.5% vs. 6.3±4.2%).After confirming the immunosuppressive function of the IL-2 treated CD3 +PD1 +TIM3 + lymphocytes, we investigated expressions of other co-inhibitory surface markers such as LAG3 and TIGIT. Amongst the cultured CD3 +PD1 +TIM3 + lymphocytes, 96.2±3.3% of the CD3 +PD1 +TIM3 + lymphocytes were LAG3 +, 28.9±5.4% of the CD3 +PD1 +TIM3 + lymphocytes were TIGIT +, and 63.7±7.8% of the cells were TIGIT -. Interestingly, CD3 +PD1 +TIM3 +LAG3 +TIGIT - lymphocytes demonstrated significantly enhanced levels of immunosuppression compared to CD3 +PD1 +TIM3 +LAG3 +TIGIT + lymphocytes (% of unstimulated T cells in CD3 +PD1 +TIM3 +LAG3 +TIGIT - lymphocytes vs. in CD3 +PD1 +TIM3 +LAG3 +TIGIT + lymphocytes, 53.8±5.5% vs. 23.2±7.4%).Conclusion.We demonstrate that treating CD3 + G-PBSCs with low-dose IL-2 markedly increases the percentage of CD3 +PD1 +TIM3 + lymphocytes, which is known to exert strong immunosuppression. Also, we suggest that CD3 +PD1 +TIM3 +LAG3 +TIGIT - lymphocytes are the subpopulation within CD3 +PD1 +TIM3 + cells that demonstrate the most potent immunosuppression compared to other subpopulations of CD3 +PD1 +TIM3 + lymphocytes. Taken together, such findings suggest that the low-dose IL-2 therapy has therapeutic potential to treat patients with GVHD. DisclosuresNo relevant conflicts of interest to declare.

Multiple Myeloma: Risk Adapted Use of Plerixafor for Stem Cell Mobilization Prior to Autologous Stem Cell Transplantation is Effective and Cost Efficient

BackgroundWe used plerixafor in ‘a risk adapted approach’ for stem cell mobilization for multiple myeloma (MM) patients prior to autologous stem cell transplantation (ASCT). Patients and MethodsBetween January, 2017 and December, 2019 105 consecutive patients of MM were recruited (Study Cohort). Patients received inj G-CSF 10 µg/kg in 2 divided doses for 5 days. Day 4 peripheral blood (PB) CD34+ count was used as a guide; if count was < 20 cells/µl, patients received plerixafor. For those with ≥ 20 cells/µl apheresis was commenced on day 5. We compared their outcome with 156 MM patients transplanted between 2012 and 2016 with G-CSF mobilized PB stem cells (Control Cohort). Primary end point was to collect ≥2.0 × 106 CD34+ cells/kg (minimal harvest). Secondary end points were: no of apheresis sessions, percentage of patients with optimal stem cell harvest (≥4.0 × 106 CD34+ cells/kg) and cost analysis. An intent to treat analysis was done. Result96.2% of patients achieved ≥ 2.0 × 106 CD34+ cells/kg in the study cohort vs. 87.2% in the control cohort, P < .01. Mean apheresis sessions were 1.5 vs. 1.7 respectively, P < .014 . Optimal stem cell harvest was 29.5% vs. 16%,P = .23. Days for neutrophil engraftment (P < 0.025) and for IV antibiotics (P < .0017) were favorable for the study cohort. Incremental cost effectiveness ratio was $ 15.80/- and $ 10.56/- per 1% increase to achieve a minimal and optimal harvest. ConclusionPlerixafor in this risk adapted strategy resulted in successful mobilization, decreased time to engraftment and was cost effective.

HLA-mismatched GPBSC infusion therapy in refractory Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis: an observational study from a single center

BackgroundHemophagocytic lymphohistiocytosis (HLH) is a severe or even fatal inflammatory state. Epstein–Barr virus (EBV) infection-associated HLH (EBV-HLH) is one of the most common secondary HLH and suffers a very poor prognosis. Allo-HSCT is often required for refractory EBV-HLH, but some patients still cannot proceed to the next allo-HSCT due to various factors. This study aimed to observe the efficacy of HLA-mismatched granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (GPBSCs) infusion for refractory EBV-HLH.MethodsA retrospective case-control study of refractory EBV-HLH patients with GPBSC infusion from HLA-mismatched donors after chemotherapy (as GPBSC group) and sole chemotherapy (as control group) was performed. Efficacy was evaluated 2 and 4 weeks and all patients were followed-up until March 1, 2018.ResultsThere were 18 cases who accepted infusion between March 2016 and Sep 2017 and 19 were randomly selected from refractory EBV-HLH patients who underwent salvage therapy during the same period for the control group. In GPBSC group, WBC (p = 0.017), Fbg (p = 0.040), and ferritin (p = 0.039) improved significantly after treatment. The overall response rate was 66.7% (CR 22.2%, PR 44.4%). However, there are no significant differences in changes of WBC, HGB, PLT, TG, Fbg, Ferritin, AST, ALT, and T-bil between two groups. Only the Fbg level was recovered better in the GPBSC infusion group (p = 0.003). In the GPBSC group, EBV-DNA decreased significantly after 2 weeks (p = 0.001) and 4 weeks (p = 0.012) after treatment, and the effect of the decrease was significantly better than that of the chemotherapy alone group in 2 weeks but not 4 weeks (p2w = 0.011, p4w = 0.145). The median survival time in the infusion group was 20.4 weeks [95% CI 10.9, 29.9], and the median survival time in the control group was 10.8 weeks [95% CI 0–24.34]. In the short-term, the infusion group’s survival rate was better (2-month 88.89% vs. 52.63%, p = 0.008; 3-month 83.33% vs. 47.09%, p = 0.012), but there was no difference in OS (p = 0.287).ConclusionsInfusing GPBSCs combined with chemotherapy is effective, especially in decreasing EBV-DNA, performs better than chemotherapy alone, and improves short-term survival rate. GPBSC infusion is suggested as a bridging treatment method to allo-HSCT.

Superior GVHD-free, relapse-free survival for G-BM to G-PBSC grafts is associated with higher MDSCs content in allografting for patients with acute leukemia

BackgroundGranulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (G-PBSC) has largely replaced unstimulated bone marrow (un-BM) for allografting because of accelerated engraftment, but with a higher morbidity and mortality of graft-versus-host-disease (GVHD). Recent studies suggested that G-CSF-primed BM (G-BM) had similar engraftment but lower morbidity and mortality of GVHD comparing to G-PBSC. A prospective, randomized, multicenter study was conducted to compare G-BM with G-PBSC as the grafts in allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute leukemia in first complete remission (CR1).MethodsTotally 101 adult leukemia in CR1 undergoing HLA-identical sibling transplants were randomized into G-BM or G-PBSC group. The primary study endpoint was GVHD-free/relapse-free survival (GRFS).ResultsBoth the engraftment of neutrophil and platelet were 2 days later in G-BM than in G-PBSC group (P = 0.412, P = 0.39). G-BM group showed significantly lower II–IV acute GVHD (aGVHD) and similar III–IV aGVHD compared with G-PBSC group (12.2% vs 28.8% for II–IV, P = 0.048; 4.1% vs 9.6% for III–IV aGVHD, P = 0.267, respectively). The overall cumulative incidence of chronic GVHD (cGVHD) at 3 years were 22.3% ± 6.3% and 44.8% ± 7.6% (P = 0.026), respectively, and extensive cGHVD were 4.5% ± 3.1% and 15% ± 5.3% (P = 0.08), respectively, in G-BM and G-PBSC groups. Two groups had similar 3-year relapse, transplant-related mortality (TRM), overall survival (OS), and disease-free survival (DFS) (all P > 0.05). G-BM group showed significantly higher probability of GRFS than G-PBSC group (73.5% ± 6.3% vs 55.8% ± 6.9% at 1 year, P = 0.049; 69.0% ± 6.7% vs 49.7% ± 7.0% at 2 and 3 years, P = 0.03, respectively). Graft content analysis revealed statistically higher frequency of myeloid-derived suppressor cells (MDSCs) in the G-BM than in G-PBSC grafts (P < 0.01), and recipients received statistically higher numbers of MDSCs in G-BM than in G-PBSC group (P = 0.045). Numbers of MDSCs infused to patients were negatively correlated with the severity of aGVHD (P = 0.032, r = −0.214). Multivariate analysis showed that MDSC cell dose below the median (HR = 3.49, P < 0.001), recipient age (HR = 2.02, P = 0.039), and high risk of disease (HR = 2.14, P = 0.018) were independent risk factors for GRFS.ConclusionsG-BM grafts lead a better GRFS and less GVHD associated with a higher MDSCs content compared with G-PBSC grafts.

The Comparison of Immune Components in Three Grafts for Stem Cell Transplantation

BackgroundRecently, a few data showed that Granulocyte-colony-stimulating factor (G-CSF) modified bone marrow (G-BM) grafts leaded a lower morbidity and mortality of graft-versus-host disease(GVHD), compared with G-CSF mobilized peripheral blood stem cells (G-PBSCs) and steady state bone marrow (SS-BM) grafts. However, the mechanism of this difference is not fully understood. In this study, we compared the immune components in the three grafts. MethodsTwenty patients undergoing HLA-matched sibling donor stem cell transplantation(SCT) were enrolled in this study. Patients were randomized to receive G-BM (n=10) or G-PBSCs (n=10) transplantation. Immune components, including Human leucocyte antigen-G (HLA-G), Myeloid-derived suppressor cells (MDSCs) and T cell subsets, were detected in bone marrow (BM) and peripheral blood (PB) of donors before and at day 5 after G-CSF mobilization. ResultsAmong 20 patients, 2 patients developed acute GVHD (aGVHD) and 5 developed chronic GVHD (cGVHD) in G-PBSCs group, and no patients developed aGVHD and only 1 developed limited cGVHD in G-BM group. For the grafts, the proportion of MDSCs in PB and BM was 1.47% ± 0.12% and 2.26% ± 0.35% (P=0.001), respectively, before mobilization. After 5 days of G-CSF mobilization, the proportion of MDSCs in PB and BM increased to be 2.73% ± 0.68% and 2.56% ± 0.12%, respectively. The increase is significant both in PB and BM (P=0.000,P=0.002, respectively), while no significant difference was found between the proportion of MDSCs in G-PB and G-BM graftes (P=0.115). The levels of HLA-G (both soluble and membrane bound) in PB and BM all increased significantly after G-CSF mobilization (all P<0.05). And the levels of HLA-G (both soluble and membrane bound) in BM were all higher than that in PB, including before and after G-CSF mobilization (all P<0.05). The total numbers of CD3+ cells were similar in BM before and after mobilization, both significantly lower than that in PB (both P<0.001). However, the lowered CD4+ cells and increased CD8+ cells in G-BM leaded to a significantly lower CD4:CD8 ratio than that in SS-BM and G-PB (both P<0.001). ConclusionsThe differences of immune components in the grafts might play a part in the different morbidity and mortality of GVHD. The higher expression of HLA-G in the grafts might be the main reason for the lower morbidity and mortality of GVHD in G-CSF-primed bone marrow transplantation. Disclosures:Liu:It was supported by 863 Program (No. 2011AA020105), National Public Health Grand Research Foundation (Grant No. 201202017).: Research Funding; It was supported by National Natural Science Foundation of China (Grant No.81000231, No.81270647) and Science and Technology Program of Guangzhou of China (11A72121174).: Research Funding.

Rejuvenation of Aged Pig Facial Skin by Transplanting Allogeneic Granulocyte Colony-Stimulating Factor-Induced Peripheral Blood Stem Cells from a Young Pig

Following a stroke, the administration of stem cells that have been treated with granulocyte colony-stimulating factor (GCSF) can ameliorate functional deficits in both rats and humans. It is not known, however, whether the application of GCSF-mobilized peripheral blood stem cells (PBSCs) to human skin can function as an antiaging treatment. We used a Lanyu pig (Sus scrofa) model, since compared with rodents, the structure of a pig's skin is very similar to human skin, to provide preliminary data on whether these cells can exert antiaging effects over a short time frame. GCSF-mobilized PBSCs from a young male Lanyu pig (5 months) were injected intradermally into the cheek skin of aged female Lanyu pigs, and tissues before and after the cell injections were compared to determine whether this treatment caused skin rejuvenation. Increased levels of collagen, elastin, hyaluronic acid, and the hyaluronic acid receptor CD44 were observed in both dermal and subcutaneous layers following the injection of PBSCs. In addition, the treated skin tissue was tighter and more elastic than adjacent control regions of aged skin tissue. In the epidermal layer, PBSC injection altered the levels of both involucrin and integrin, indicating an increased rate of epidermal cell renewal as evidenced by reductions in both cornified cells and cells of the spinous layers and increases in the number of dividing cells within the basal layer. We found that the exogenous PBSCs, visualized using fluorescence in situ hybridization, were located primarily in hair follicles and adjacent tissues. In summary, PBSC injection restored young skin properties in the skin of aged (90 months) pigs. On the basis of our preliminary data, we conclude that intradermal injection of GCSF-mobilized PBSCs from a young pig can rejuvenate the skin in aged pigs.

Factors influencing engraftment in HLA-haploidentical/mismatch related transplantation with combined granulocyte-colony stimulating factor-mobilized peripheral blood and bone marrow for patients with leukemia

Unmanipulated HLA-haploidentical/mismatch related transplantation with combined granulocyte-colony stimulating factor-mobilized peripheral blood stem cells (G-PBSCs) and granulocyte-colony stimulating factor-mobilized bone marrow (G-BM) has been used as an alternative transplantation strategy for patients without an HLA-matched donor. In this transplantation setting, factors associated with hematopoietic recovery have not been defined completely. The aim of this study was to investigate the factors influencing the engraftment in this transplantation setting for patients with leukemia. The study group comprised 104 patients with leukemia who underwent transplantation at a single institution between 2005 and 2008. Factors correlating with neutrophil and platelet engraftment post-transplantation were analyzed retrospectively. All patients achieved an absolute neutrophil count of 500/μL with a mean time of 13.6 days (range 8–20 days) and a platelet count over 20 × 10 9/L with a mean time of 20.2 days (range 16–26 days). In univariate analysis, donor and age were associated with increased risk of neutrophil engraftment, but their significance was lost upon multivariate analysis. The sex, age, donor, CD34 + cell dose, conditioning regimen, mismatched locus, ABO mismatched and diagnosis have no effect on platelet engraftment. Our results suggest that it is an ideal approach to treat patients with leukemia with HLA-haploidentical/mismatched related transplantation with combined G-PBSCs and G-BM for a high level of stem cells without delayed engraftment.

Cost and outcome in stem cell collections in HLA-haplo identical/mismatched related transplantation with combined granulocyte-colony stimulating factor -mobilized blood and bone marrow for patients with hematologic malignancies

Unmanipulated HLA-haplo identical/mismatched related transplantation with combined granulocyte-colony stimulating factor -mobilized peripheral blood stem cells (G-PBSCs) and granulocyte-colony stimulating factor-mobilized bone marrow (G-BM) has been developed as an alternative transplantation strategy for patients without an HLA-matched related or unrelated donor. In this transplantation setting, the cost and outcome of stem cell collections have not been defined completely. The aim of this study was to compare the cost and outcome of stem cell collection in HLA-haplo identical/mismatched related transplantation with combined G-PBSCs and G-BM to the HLA-identical/matched transplantation with G-PBSCs alone for patients with hematologic malignancies. Hundred and fifty-two healthy donors received twice-daily granulocyte-colony stimulating factor (G-CSF) subcutaneously for 5 days. The PBSCs were collected on day 4 and 5 of G-CSF treatment for HLA-identical/matched transplantation from unrelated/related donors. The PBSC collections and BM harvests was performed on day 4 and 5 of G-CSF treatment for HLA-haplo identical/mismatched related transplantation from related donors, respectively. There was no difference in the major characteristics between groups. More stem cells were harvested in HLA-haplo identical/mismatched related donors than that of HLA-identical/matched donors and a lower cost was seen in the former. The HLA-haplo identical/mismatched related transplantation with combined G-PBSCs and G-BM was a feasible approach with high cell harvest and low cost of stem cell collection for patients with hematologic malignancies.

Role of Antithymocyte Globulin and Granulocyte-Colony Stimulating Factor-Mobilized Bone Marrow in Allogeneic Transplantation for Patients with Hematologic Malignancies

The main obstacle for allogeneic transplantation is delayed hematologic reconstitution and serious graft-versus-host disease (GVHD). The results of 128 patients with hematologic malignancies undergoing HLA -identical (n = 52) or HLA-haploidentical/mismatched (n = 76) hematopoietic stem cell transplantation (HSCT) performed during the same time period were compared. Patients with HLA-identical HSCT received unmanipulated granulocyte-colony stimulating factor -mobilized peripheral blood stem cells (G-PBSCs). Forty-six patients with HLA-haploidentical related HSCT received antithymocyte globulin (ATG) in conditioning regimens followed by the transplantation of the combination of unmanipulated G-PBSCs and granulocyte-colony stimulating factor -mobilized bone marrow (G-BM) and 30 patients with HLA-mismatched unrelated HSCT received ATG in conditioning regimens followed by the transplantation of unmanipulated G-PBSCs. All patients got successful hematopoietic engraftment. The cumulative incidences of grades I to II acute GVHD (aGVHD) on day 100 in the identical, haploidentical related and mismatched unrelated cohorts were 21.2%, 43.5%, and 53.3%, respectively. The cumulative incidences of chronic GVHD (cGVHD) in the identical, mismatched unrelated, and haploidentical related cohorts were 34.6%, 33.3%, and 10.9%, respectively. The 2-year relapse and treatment-related mortality (TRM) rates were 19.2%, 23.9%, 23.3%, and 9.6%, 8.7%, 10% for patients who underwent identical, HLA-haploidentical related, and mismatched unrelated transplantation, respectively. The 2-year probabilities of leukemia-free survival and overall survival were 72.2%, 70.6%, 68.1%, and 76.5%, 77.8%, 70.0% after identical, haploidentical related and mismatched unrelated transplantations, respectively. Multivariate analyses showed that only advanced disease stage and a diagnosis of disease had increased risk of relapse, treatment failure, and overall mortality. In conclusion, it is a feasible approach with acceptable outcomes for patients undergoing HLA-haploidentical related HSCT by the combination of G-PBSCs and G-BM with conditioning regimens including ATG.

Comparison of outcomes after transplantation of peripheral blood stem cells versus bone marrow following an identical nonmyeloablative conditioning regimen

This is the first study to examine the outcomes in 54 patients with hematologic malignancies who received an HLA-matched related donor bone marrow (BM, n = 42) or GCSF-mobilized peripheral blood stem cells (PBSC, n = 12) following identical nonmyeloablative conditioning with the intention of induction of mixed chimerism (MC) followed by prophylactic donor leukocyte infusion (pDLI) to convert MC to full donor chimerism (FDC) and capture a graft-versus-tumor effect without clinical graft-versus-host disease (GVHD). Neutrophil and platelet recovery were faster and transfusion requirement was less in PBSC recipients (P < 0.05). A total of 48% of BMT recipients achieved FDC with a median conversion time of 84 days, including 13 following pDLI. In contrast, 83% (P = 0.04) in the PBSC group had spontaneous FDC at a median of 14 days, precluding the administration of pDLI. There was no significant difference in the incidences of acute or chronic GVHD, though the rates of chronic GVHD were considerably higher in PBSC group than in the BM group (6/7, 86% vs 10/24, 42%). CD4 and CD8 T-cell recovery was faster in PBSC recipients. In PBSC recipients, a higher number of CD34+ cells was associated with increased rates of severe, grade III-IV acute GVHD.

Comparable Survival and Transplant-Related Mortality Following Allogeneic Hematopoietic Cell Transplantation from HLA Allele-Matched Unrelated and HLA-Identical Sibling Donors.

Comprehensive analyses of unrelated donor (URD) and recipient HLA-matching for allogeneic hematopoietic cell transplantation (AHCT) have demonstrated better outcomes when allele typing is performed using high-resolution nucleotide sequence-based techniques. To evaluate survival following myeloablative AHCT using allele-level HLA-matched URD as compared with HLA-identical sibling donors, we analyzed outcomes for 430 patients treated at our center between March 1991 and April 2005. Sequence-based allele typing was retrospectively performed for HLA-A, B, C, DR and DQ when not done at time of AHCT for URD (n = 124; 29%) and non-sibling related donors (n = 19; 4%). Donors were HLA-identical siblings (n = 276; 64%), HLA allele-matched URD (n = 52; 12%), single HLA-locus mismatched donors (n = 52; 12%), or > 1 locus mismatched donors (n = 50; 12%). The median age at transplant was 23.4 years (range: 0.2 – 61). The most common diagnoses were AML (n = 107; 25%), CML (n = 90; 21%), ALL (n = 86; 20%) and MDS (n = 50; 12%). Total body irradiation-based preparative regimens were used for 283 patients (66%). Bone marrow (BM) was the graft for 388 patients (90%) and GCSF-mobilized peripheral blood stem cells (PBSC) for the remaining 42 (10%). Graft-versus-host disease (GVHD) prophylaxes were cyclosporine and methotrexate (n = 327; 76%), long methotrexate (n = 42; 10%), T-cell depletion (n = 19; 4%), or other regimens (n = 42; 10%). With a median follow-up of 4.8 years (range: 0.2 – 12.1), the 5-year estimate of overall survival (OS) for the entire group was 48.2% (95% CI: 45.7 – 50.7) and transplant-related mortality (TRM) was 31.4% (95% CI: 28.8 – 34). As shown in the Table, OS and TRM were indistinguishable between AHCT performed with HLA-identical siblings compared with HLA allele-matched URD. There was also no difference in grade III – IV acute GVHD (P = .46) between these two groups whereas there was a trend towards more extensive chronic GVHD (HR 1.8; 95% CI: 0.9 – 3.6; P = 0.12) for the URD recipients. Using a multivariate analysis to adjust for advanced disease, age (> vs ≤ 30 years), graft (BM vs PBSC) and female-to-male gender mismatch, there remained no difference in OS between HLA-identical siblings and HLA allele-matched URD (P = 0.67). These results demonstrate that key outcomes (OS, TRM, and severe acute GVHD) are equivalent in recipients of grafts from either allele-level 10/10 HLA-matched URD or HLA-identical siblings.Overall SurvivalTRMNumberHazard Ratio95% CIP valueHazard Ratio95% CIP valueHLA-ID Sibling2761--1--HLA-ID URD521.10.7 – 1.70.670.80.4 – 1.60.581 Locus MM521.30.9 – 2.00.191.40.8 – 2.40.25> 1 Locus MM502.01.4 – 2.9< 0.0012.61.7 – 4.1< 0.001

Development of Late over Early Full Donor Chimerism (FDC) Results in Improved Progression-Free and Overall Survival in Patients with Advanced Malignant Lymphomas Receiving Nonmyeloablative Allogeneic Hematopoietic Stem Cell Transplantation (HSCT).

Mixed chimerism (MC) can be induced in mice after non-myeloablative conditioning and allogeneic HSCT. Full donor hematopoiesis conversion from MC can occur when nontolerant donor lymphocyte infusions (DLI) are given weeks following the transplant as a result of lymphohematopoietic GVH reactions that eradicate leukemia/lymphoma without GVHD. Based on this murine model, we initiated a trial in patients with advanced hematologic malignancies of non-myeloablative therapy with HLA-matched related donor HSCT with intentional induction of MC followed by prophylactic DLI (pDLI) at day +35 post-HSCT in those without clinical GVHD. This analysis examines the influence of the kinetics of sustained donor lymphoid (CD3+ cells) chimerism on transplant outcomes. Fifty-four patients with advanced hematologic malignancies received nonmyeloablative preparative therapy (cyclophosphamide, equine antithymocyte globulin, thymic irradiation and a brief course of cyclosporine) and HLA-matched HSCT (bone marrow, BM, n=42; GCSF-mobilized peripheral blood stem cells, PBSC, n=12). Chimerism analyses were performed weekly until day +100 post-HSCT and then once monthly for a year. Twenty-nine patients with aggressive malignant lymphomas (NHL, n=21; HD, n=8) were selected out of 50 evaluable patients in an effort to analyze a relatively uniform group in terms of their disease and sustained chimerism; patients who lost the allograft were removed from this analysis. Twenty five patients attained stable FDC, defined as > or = 90% donor T cells, and 4 maintained stable MC. Using 42 days post-HSCT as the defining point for chimerism conversion 13 patients achieved early FDC and 16 patients achieved late FDC. Median time to achieve FDC in the early and late groups was 14 days (range, 7–42) and 70 days (range, 49–91) respectively. Separation produced fairly equal distribution by disease characteristics as follows (early to late): NHL, 10 to 11 and HD, 3 to 5. The early group included 10 PBSC recipients who did not receive pDLI because of the spontaneous conversion to FDC; in contrast, the majority of the late group received BMT and 13 of them received DLI (pDLI, n=10, therapeutic DLI, n=3). The incidence of acute GVHD (grades II–IV) was similar between the early and late groups with rates of 77% (n=10 of 13) and 69% (n=11 of 16) respectively; for chronic GVHD, there was a tendency toward an increased rate in the early group of 75% (3/4) compared to the late group rate of 63% (5/8). Overall disease response rates in the early and late groups were 62% and 69%, but there was a trend toward improved complete remission rates in the late group relative to the early group (50% vs 31%). Progression-free survival (PFS) and overall survival (OS) at 1 year were improved in the late compared to the early group [31% (5/16) vs 15% (2/13) and 50% (8/16) vs 38% (5/13), respectively]. At 5 years, there was a statistically significant improved PFS and OS rate in the late group over the early group [31% (5/16) vs 0% (0/13), p =0.037, for both PFS and OS]. In conclusion, these data support the observation from our mouse models that the most potent graft-vs-tumor effect occurs in mixed chimeras with late chimerism conversion, often after delayed pDLI.

Ex vivo expansion of immature 4-hydroperoxycyclophosphamide-resistant progenitor cells from G-CSF-mobilized peripheral blood.

The application of ex vivo expansion to cell products pharmacologically purged in vitro may provide sufficient numbers of cells for rapid engraftment in a product with reduced tumor burden. To pursue this possibility we evaluated the effect of 4-hydroperoxycyclophosphamide (4-HC) treatment on granulocyte colony-stimulating factor-mobilized peripheral blood stem cells (G-PBSC) and their subsequent expansion potential. A small number of G-PBSC CD34+ cells are resistant to 4-HC and are phenotypically and functionally immature. 4-HC-resistant G-PBSC cells are CD34+ bright, CD38+/-, DR(lo), CD13(lo), CD33-, CD71-, and rhodamine dull. In six experiments, treating G-PBSC with 60 microg/mL of 4-HC at 37 degrees C for 30 minutes reduced the number of colony-forming units (CFUs) per 5000 CD34+ cells by 96.3% (from 1333 +/- 137 to 46.5 +/- 11). This purging also reduced the frequency of 5-week long-term culture initiating cells (LTC-ICs) from 1/39 (range 1/27 to 1/62) to <1/1680 (range 1/1180 to 1/2420). Ex vivo expansion cultures were used to compare the proliferative potential of treated and untreated CD34+ cells. These cells were cultured with either the HS-5 stromal cell line serum-deprived conditioned media supplemented with 10 ng/mL kit ligand (HS-5CM/KL) or a recombinant growth factor mix (GFmix) containing 10 ng/mL each of interleukin (IL)-1, IL-3, IL-6, KL, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and 3 U/mL of erythropoietin. Culturing untreated CD34+ G-PBSC with 10% HS-5CM/KL increased total nucleated cells by 460-fold after 15 days. Progenitors, which were measured as CFUs, also increased by 47-fold over the same period. More significantly, culturing the 4-HC-treated CD34+ cells with HS-5/KL increased CFUs 98-fold and the nucleated cells increased 4573-fold. The absolute number of CFUs present after expansion of the 4-HC-resistant cells with HS-5CM/KL was threefold higher than that detected before purging and significantly higher than that obtained with GFmix. These data indicate that G-PBSC contain a very immature pool of cells not detectable using the 5-week LTC-IC assay, but have extremely high proliferative potential. Additionally, pharmacological purging of G-PBSC greatly reduces mature cells while retaining an immature population. Also significant is the finding that supernatant from the HS-5 bone marrow stromal cell line plus KL can fully regenerate progenitors from the 4-HC-resistant CD34+ G-PBSC.

Generation of human natural killer cells from peripheral blood CD34+ cells mobilized by granulocyte colony-stimulating factor.

We studied the generation of human natural killer (NK) cells from CD34+ cells that were isolated from peripheral blood stem cells (PBSC) mobilized by granulocyte colony-stimulating factor (g-CSF). The isolated CD34+ cells were cultured in the presence of a combination of interleukin-1 (IL-1alpha), IL-2, and stem cell factor for 5 weeks without marrow stroma. We found that the CD34+ cells isolated from G-CSF-mobilized PBSC (G-CSF/PBSC) could differentiate into a population of NK cells which were CD56+(bright)/CD3- and showed morphologic characteristics of large granular lymphocytes. Immunophenotypic analysis of the NK cells thus generated showed that a small proportion of them expressed CD2, CD8 and CD16 surface markers and approximately half of them coexpressed CD7. This NK population exhibited cytotoxic activity against a NK-sensitive cell line, K562. These observations suggest that CD34+ cells from G-CSF/PBSC contain precursors of NK cells that can differentiate into functional NK cells.