Selection of optimal alternative graft source: mismatched unrelated donor, umbilical cord blood, or haploidentical transplant. Blood. 2012;119:1972-1980. [PMID: 22210876 DOI: 10.1182/blood-2011-11-354563]

Haploidentical Donors: Can Faster Transplantation Be Life-Saving for Patients with Advanced Disease?

Haploidentical stem cell transplantation is a therapeutic option for patients without an HLA-matched donor. It is increasingly being used worldwide due to the application of posttransplantation cyclophosphamide and is associated with lower incidence of graft-versus-host disease and treatment-related mortality. Haploidentical donors are generally available for most patients and stem cells can be rapidly obtained. Delays in transplantation while waiting for unrelated donor cells can be potentially problematic for patients with advanced disease at risk for progression; thus, the use of haploidentical donors, especially in this setting, can be life-saving. Here we reviewed the literature on haploidentical stem cell transplantation performed with posttransplantation cyclophosphamide.

Haploidentical, G-CSF-primed, unmanipulated bone marrow transplantation for patients with high-risk hematological malignancies: an update

Ninety-seven patients affected by high-risk hematological malignancies underwent G-CSF primed, unmanipulated bone marrow (BM) transplantation from a related, haploidentical donor. All patients were prepared with an identical conditioning regimen including Thiotepa, Busilvex, Fludarabine (TBF) and antithymocyte globulin given at myeloablative (MAC = 68) or reduced (reduced intensity conditioning (RIC) = 29) dose intensity and received the same GvHD prophylaxis consisting of the combination of methotrexate, cyclosporine, mycofenolate-mofetil and basiliximab. Patients were transplanted in 1st or 2nd CR (early phase: n = 60) or in > 2nd CR or active disease (advanced phase: n = 37). With a median time of 21 days (range 12-38 days), the cumulative incidence (CI) of neutrophil engraftment was 94 ± 3%. The 100-day CI of III-IV grade acute GvHD and the 2-year CI of extensive chronic GvHD were 9 ± 3% and 12 ± 4%, respectively. Overall, at a median follow-up of 2.2 years (range 0.3-5.6), 44 out of 97 (45%) patients are alive in CR. The 5-year probability of overall survival (OS) and disease-free survival (DFS) for patients in early and advanced phase was 53 ± 7 vs 24 ± 8% (P = 0.006) and 48 ± 7 vs 22 ± 8% (P = 0.01), respectively. By comparing MAC with RIC patient groups, the transplant-related mortality was equivalent (36 ± 6 vs 28 ± 9%) while the relapse risk was lower for the MAC patients (22 ± 6 vs 45 ± 11%), who showed higher OS (48 ± 7 vs 29 ± 10%) and DFS (43 ± 7 vs 26 ± 10%). However, all these differences did not reach a statistical significance. In multivariate analysis, diagnosis and recipient age were significant factors for OS and DFS. In conclusion, this analysis confirms, on a longer follow-up and higher number of patients, our previous encouraging results obtained by using MAC and RIC TBF regimen as conditioning for G-CSF primed, unmanipulated BM transplantation from related, haploidentical donor in patients with high-risk hematological malignancies, lacking an HLA-identical sibling or unrelated donor and in need to be urgently transplanted.

Deep-sequencing of the T-cell receptor repertoire in patients with haplo-cord and matched-donor transplants

Haplo-cord transplant has emerged as a feasible and reliable approach for haematopoietic stem cell transplant in patients who are unable to find matched-donor. This approach provides fast myeloid recovery, low incidence of graft vs host disease (GVHD) and favorable graft versus leukemia (GVL) effects. T cell recovery plays an important role in preventing infectious complications; it also mediates the GVHD and the GVL effects. Here, we utilized a novel RNA-based sequencing approach to quantitatively characterize the T cell receptor (TCRs) repertoire in patients underwent haplo-cord transplant in comparison with those underwent matched-donor transplant. Our study shows that higher percentage of cord cells early post transplant were associated with significantly higher TCR diversity. TCR diversity was significantly lower in patients with GVHD and in relapsed patients. A larger cohort study is needed to validate these data and to provide useful information on the specific TCR clones correlated with clinical outcome.

Alternative donor transplantation--"mixing and matching": the role of combined cord blood and haplo-identical donor transplantation (haplo-cord SCT) as a treatment strategy for patients lacking standard donors?

In the past decade, haplo-cord stem cell transplantation (SCT) using myeloablative or reduced intensive conditioning regimens has been shown to result in reliable and fast engraftment of neutrophils and platelets comparable to HLA-matched donors and much faster than after cord stem cell transplant. Haplo-cord SCT also has a low incidence of early non-relapse mortality, low incidences of acute and chronic graft-vs-host disease (GVHD), and excellent graft-vs-leukemia (GVL) effects. Favorable long-term outcomes for high-risk patients with hematologic malignancies have been reported, including older patients. Haplo-cord SCT will likely overcome the limitations of cell dose during cord stem cell selection and might significantly expand the use of cord stem cell transplant in the adult population. The comparable survival outcomes of matched related donor (MRD), matched unrelated donor (MUD), and haplo-cord stem cell transplant strongly argue that haplo-cord SCT should be considered as effective alternative stem cell transplant for high-risk patients lacking standard donors. Further improvement in supportive care and incorporation of a better understanding of the human fetal immune development into the haplo-cord SCT are required to further improve this strategy.

Direct Comparison of Wharton's Jelly and Bone Marrow-Derived Mesenchymal Stromal Cells to Enhance Engraftment of Cord Blood CD34(+) Transplants

Cotransplantation of CD34(+) hematopoietic stem and progenitor cells (HSPCs) with mesenchymal stromal cells (MSCs) enhances HSPC engraftment. For these applications, MSCs are mostly obtained from bone marrow (BM). However, MSCs can also be isolated from the Wharton's jelly (WJ) of the human umbilical cord. This source, regarded to be a waste product, enables a relatively low-cost MSC acquisition without any burden to the donor. In this study, we evaluated the ability of WJ MSCs to enhance HSPC engraftment. First, we compared cultured human WJ MSCs with human BM-derived MSCs (BM MSCs) for in vitro marker expression, immunomodulatory capacity, and differentiation into three mesenchymal lineages. Although we confirmed that WJ MSCs have a more restricted differentiation capacity, both WJ MSCs and BM MSCs expressed similar levels of surface markers and exhibited similar immune inhibitory capacities. Most importantly, cotransplantation of either WJ MSCs or BM MSCs with CB CD34(+) cells into NOD SCID mice showed similar enhanced recovery of human platelets and CD45(+) cells in the peripheral blood and a 3-fold higher engraftment in the BM, blood, and spleen 6 weeks after transplantation when compared to transplantation of CD34(+) cells alone. Upon coincubation, both MSC sources increased the expression of adhesion molecules on CD34(+) cells, although stromal cell-derived factor-1 (SDF-1)-induced migration of CD34(+) cells remained unaltered. Interestingly, there was an increase in CFU-GEMM when CB CD34(+) cells were cultured on monolayers of WJ MSCs in the presence of exogenous thrombopoietin, and an increase in BFU-E when BM MSCs replaced WJ MSCs in such cultures. Our results suggest that WJ MSC is likely to be a practical alternative for BM MSC to enhance CB CD34(+) cell engraftment.

Impact of the source of hematopoietic stem cell in unrelated transplants: comparison between 10/10, 9/10-HLA matched donors and cord blood

In absence of available matched-related or unrelated donor (MUD), mismatched unrelated donors (MMUD) and unrelated cord blood (UCB) are both considered to be suitable donors, with similar post-transplant overall survival. In most of these retrospective comparisons, HLA typing of adult donors was performed at eight loci. The aim of this study was to compare the outcome of patients transplanted from UCB (N = 64) with those transplanted from 9/10-HLA MMUD (N = 84) or 10/10-HLA MUD (N = 196). In multivariate analysis, UCB was associated with less Grade II-IV acute GVHD in comparison with MUD (aHR 1.97, 95% CI 1.19-3.27, P = 0.009) and MMUD transplants (aHR 1.79, 95% CI 1.02-3.15, P = 0.042), while the cumulative incidence of chronic GVHD was not significantly different between the three groups. Overall survival (OS), non-relapse mortality, and relapse were not different between MMUD and UCB transplantation, whereas OS was impaired after UCB in comparison with MUD (aHR 0.65, 95% CI 0.43-0.99, P = 0.043). Factors also impacting OS were the donor/recipient CMV serostatus (Donor-/Recipient+ aHR 1.76, 95% CI 1.23-2.52, P = 0.002 compared with D-/R-), the donor/recipient gender combination (Female/Male versus other combinations aHR 1.57, 95% CI 1.11-2.22, P = 0.012) and disease risk (aHR 1.58, 95% CI 1.05-2.38, P = 0.027 for high vs. low risk disease). Our data confirm that UCB and 9/10-HLA MMUD are both relevant alternative options when no 10/10-HLA donor is available. Donor/recipient gender combination and CMV serostatus had a significant impact on survival and may be taken into account, along with donor type, in the setting of MMUD and UCB transplants.

Thrombopoietin treatment of one graft in a double cord blood transplant provides early platelet recovery while contributing to long-term engraftment in NSG mice

Human cord blood (CB) hematopoietic stem cell (HSC) transplants demonstrate delayed early neutrophil and platelet recovery and delayed longer term immune reconstitution compared to bone marrow and mobilized peripheral blood transplants. Despite advances in enhancing early neutrophil engraftment, platelet recovery after CB transplantation is not significantly altered when compared to contemporaneous controls. Recent studies have identified a platelet-biased murine HSC subset, maintained by thrombopoietin (TPO), which has enhanced capacity for short- and long-term platelet reconstitution, can self-renew, and can give rise to myeloid- and lymphoid-biased HSCs. In previous studies, we have shown that transplantation of human CB CD34(+) cells precultured in TPO as a single graft accelerates early platelet recovery as well as yielding long-term repopulation in immune-deficient mice. In this study, using a double CB murine transplant model, we investigated whether TPO cultured human CB CD34(+) cells have a competitive advantage or disadvantage over untreated human CB CD34(+) cells in terms of (1) short-term and longer term platelet recovery and (2) longer term hematological recovery. Our studies demonstrate that the TPO treated graft shows accelerated early platelet recovery without impairing the platelet engraftment of untreated CD34(+) cells. Notably, this was followed by a dominant contribution to platelet production through the untreated CD34(+) cell graft over the intermediate to longer term. Furthermore, although the contribution of the TPO treated graft to long-term hematological engraftment was reduced, the TPO treated and untreated grafts both contributed significantly to long-term chimerism in vivo.

Combination of a Haploidentical Stem Cell Transplant With Umbilical Cord Blood for Cerebral X-Linked Adrenoleukodystrophy

BACKGROUND

Childhood cerebral X-linked adrenoleukodystrophy is a rapidly progressive neurodegenerative disorder that affects central nervous system myelin and the adrenal cortex. Hematopoietic stem cell transplantation is the best available curative therapy if performed during the early stages of disease. Only 30% of patients who might benefit from a hematopoietic stem cell transplant will have a full human leukocyte antigen-matched donor, which is considered to be the best choice.

PATIENT DESCRIPTION

We present a 5-year-old boy with cerebral X-linked adrenoleukodystrophy whose brain magnetic resonance imaging severity score was 7 and who needed an immediate transplantation without an available full human leukocyte antigen-matched donor. We combined haploidentical and umbilical cord blood sources for transplantation and saw encouraging results. After transplantation, the patient showed neurological stability for 6 months and the level of very long chain fatty acids had decreased. By 1 year, the patient appeared to gradually develop cognition, motor, and visual disturbances resulting from possible mix chimerism.

CONCLUSION

Transplantation of haploidentical stem cells combined with the infusion of umbilical cord blood is a novel approach for treating cerebral X-linked adrenoleukodystrophy. It is critical to monitor posttransplant chimerism and carry out antirejection therapy timely for a beneficial clinical outcome.

Umbilical cord blood donation: public or private?

Umbilical cord blood (UCB) is a graft source for patients with malignant or genetic diseases who can be cured by allogeneic hematopoietic cell transplantation (HCT), but who do not have an appropriately HLA-matched family or volunteer unrelated adult donor. Starting in the 1990s, unrelated UCB banks were established, accepting donations from term deliveries and storing UCB units for public use. An estimated 730 000 UCB units have been donated and stored to date and ~35 000 UCB transplants have been performed worldwide. Over the past 20 years, private and family banks have grown rapidly, storing ~4 million UCB units for a particular patient or family, usually charging an up-front and yearly storage fee; therefore, these banks are able to be financially sustainable without releasing UCB units. Private banks are not obligated to fulfill the same regulatory requirements of the public banks. The public banks have released ~30 times more UCB units for therapy. Some countries have transitioned to an integrated banking model, a hybrid of public and family banking. Today, pregnant women, their families, obstetrical providers and pediatricians are faced with multiple choices about the disposition of their newborn's cord blood. In this commentary, we review the progress of UCB banking technology; we also analyze the current data on pediatric and adult unrelated UCB, including the recent expansion of interest in transplantation for hemoglobinopathies, and discuss emerging studies on the use of autologous UCB for neurologic diseases and regenerative medicine. We will review worldwide approaches to UCB banking, ethical considerations, criteria for public and family banking, integrated banking ideas and future strategies for UCB banking.

Early-phase differences in health-related quality of life, psychological status, and physical function between human leucocyte antigen-haploidentical and other allogeneic haematopoietic stem cell transplantation recipients

PURPOSE

This study investigated the differences between allogeneic haematopoietic stem cell transplantation (allo-HSCT) patients receiving HSC from human leucocyte antigen (HLA)-haploidentical donors (HID) and other donors that included HLA-matched sibling, matched unrelated, and unrelated umbilical cord blood donors in the 6 weeks after HSCT with respect to quality of life (QOL), psychological status, and physical function.

METHODS

The study included 126 patients (HID group, n = 100; other donor group, n = 26) who underwent allo-HSCT between July 2007 and December 2012. Patients were evaluated for health-related QOL using the Medical Outcome Study 36-item Short Form Health Survey. Psychological status was measured by Hospital Anxiety and Depression Scale. Physical function was assessed using tests for handgrip strength, knee extensor strength, and the 6-min walk test.

RESULTS

After HSCT, the HID group showed significantly greater improvements in the general health subscale and Mental Component Summary (MCS) of QOL than the other donor group (P < 0.01). Multivariate analysis confirmed that complete remission and age were associated with changes in the general health subscale before and after HSCT (P < 0.05). With regard to physical function, the HID group showed significantly more decline than the other donor group with respect to handgrip strength and knee extensor muscle strength after HSCT (P < 0.05). Total corticosteroid dose was associated with decreased handgrip strength before and after HSCT (P < 0.05).

CONCLUSIONS

The donor type affects QOL, psychological status, and physical function in allo-HSCT recipients; these findings may provide insights for customised rehabilitation strategies for HSCT recipients.

Single-institution Experience of Unrelated Cord Blood Transplantation for Primary Immunodeficiency

Pediatric patients with primary immunodeficiencies (PID) constitute life-threatening medical emergencies. In the absence of an HLA-identical hematopoietic stem cell donor, unrelated donor cord blood transplantation (CBT) is another treatment option. There are little data regarding the outcome of unrelated CBT for PID in Taiwan. We report the results of CBT performed in 8 patients with PID between 2004 and 2013 at Chang Gung Memorial Hospital. The cases included severe combined immunodeficiency (n=4), chronic granulomatous disease (n=2), Wiskott-Aldrich syndrome (n=1), and T-cell immunodeficiency (n=1). Median follow-up time was 73 months. Most UCB recipients received a myeloablative conditioning regimen. There were 7 boys and 1 girl with a median age of 2.5 months at diagnosis (range, antenatal to 17 mo). Median age at transplant was 5.5 months (range, 2 to 74 mo). All but 1 patients engrafted at a median time of 14 days. One developed significant grade III graft-versus-host disease after transplant. Our data show that unrelated CBT in PID is possible. However, no definite conclusions can be drawn from this small number of patients, and more studies are needed to further investigate and confirm these findings.

Effect of cord blood processing on transplantation outcomes after single myeloablative umbilical cord blood transplantation

Variations in cord blood manufacturing and administration are common, and the optimal practice is not known. We compared processing and banking practices at 16 public cord blood banks (CBB) in the United States and assessed transplantation outcomes on 530 single umbilical cord blood (UCB) myeloablative transplantations for hematologic malignancies facilitated by these banks. UCB banking practices were separated into 3 mutually exclusive groups based on whether processing was automated or manual, units were plasma and red blood cell reduced, or buffy coat production method or plasma reduced. Compared with the automated processing system for units, the day 28 neutrophil recovery was significantly lower after transplantation of units that were manually processed and plasma reduced (red cell replete) (odds ratio, .19; P = .001) or plasma and red cell reduced (odds ratio, .54; P = .05). Day 100 survival did not differ by CBB. However, day 100 survival was better with units that were thawed with the dextran-albumin wash method compared with the "no wash" or "dilution only" techniques (odds ratio, 1.82; P = .04). In conclusion, CBB processing has no significant effect on early (day 100) survival despite differences in kinetics of neutrophil recovery.

Salvaged single-unit cord blood transplantation for 26 patients with hematologic malignancies not in remission

Treatments for patients with hematologic malignancies not in remission are limited, but a few clinical studies have investigated the effects of salvaged unrelated cord blood transplantation (CBT). We retrospectively studied 19 patients with acute leukemia, 5 with myelodysplastic syndrome (MDS with refractory anemia with excess blasts [RAEB]), and 2 with non-Hodgkin's lymphoma who received 1 CBT unit ≤2 loci human leukocyte antigen (HLA)-mismatched after undergoing myeloablative conditioning regimens between July 2005 and July 2014. All of them were in non-remission before transplantation. The infused total nucleated cell (TNC) dose was 4.07 (range 2.76-6.02)×10⁷/kg and that of CD34⁺ stem cells was 2.08 (range 0.99-8.65)×10⁵/kg. All patients were engrafted with neutrophils that exceeded 0.5×10⁹/L on median day +17 (range 14-37 days) and had platelet counts of >20×10⁹/L on median day +35 (range 17-70 days). Sixteen patients (61.5%) experienced pre-engraftment syndrome (PES), and six (23.1%) patients progressed to acute graft-versus-host disease (GVHD). The cumulative incidence rates of II-IV acute GVHD and chronic GVHD were 50% and 26.9%, respectively. After a median follow-up of 27 months (range 5-74), 14 patients survived and 3 relapsed. The estimated 2-year overall survival (OS), disease-free survival (DFS), and non-relapse mortality (NRM) rates were 50.5%, 40.3%, and 35.2%, respectively. Salvaged CBT might be a promising modality for treating hematologic malignancies, even in patients with a high leukemia burden.

Enforced fucosylation of cord blood hematopoietic cells accelerates neutrophil and platelet engraftment after transplantation

Delayed engraftment is a major limitation of cord blood transplantation (CBT), due in part to a defect in the cord blood (CB) cells' ability to home to the bone marrow. Because this defect appears related to low levels of fucosylation of cell surface molecules that are responsible for binding to P- and E-selectins constitutively expressed by the marrow microvasculature, and thus for marrow homing, we conducted a first-in-humans clinical trial to correct this deficiency. Patients with high-risk hematologic malignancies received myeloablative therapy followed by transplantation with 2 CB units, one of which was treated ex vivo for 30 minutes with the enzyme fucosyltransferase-VI and guanosine diphosphate fucose to enhance the interaction of CD34(+) stem and early progenitor cells with microvessels. The results of enforced fucosylation for 22 patients enrolled in the trial were then compared with those for 31 historical controls who had undergone double unmanipulated CBT. The median time to neutrophil engraftment was 17 days (range, 12-34 days) compared with 26 days (range, 11-48 days) for controls (P = .0023). Platelet engraftment was also improved: median was 35 days (range, 18-100 days) compared with 45 days (range, 27-120 days) for controls (P = .0520). These findings support ex vivo fucosylation of multipotent CD34(+) CB cells as a clinically feasible means to improve engraftment efficiency in the double CBT setting. The trial is registered to www.clinicaltrials.gov as #NCT01471067.

No Synergistic Effect of Cotransplantation of MSC and Ex Vivo TPO-Expanded CD34(+) Cord Blood Cells on Platelet Recovery and Bone Marrow Engraftment in NOD SCID Mice

After cord blood (CB) transplantation, early platelet recovery in immune-deficient mice is obtained by expansion of CB CD34(+) cells with thrombopoietin (TPO) as single growth factor. Moreover, improvement of hematopoietic engraftment has been shown by cotransplantation of mesenchymal stem cells (MSC). We investigated whether a combination of both approaches would further enhance the outcome of CB transplantation in NOD SCID mice. NOD SCID mice were transplanted with either CB CD34(+) cells, CD34(+) cells with MSC, TPO-expanded CD34(+) cells or TPO-expanded CD34(+) cells with MSC. We analyzed human platelet recovery in the peripheral blood (PB) from day 4 after transplantation onward and human bone marrow (BM) engraftment at week 6. The different transplants were assessed in vitro for their migration capacity and expression of CXCR4. TPO expansion improved the early platelet recovery in the PB of the mice. Cotransplantation of MSC with CD34(+) cells improved BM engraftment and platelet levels in the PB 6 weeks after transplantation. Combining TPO expansion and MSC cotransplantation, however, neither resulted in a more efficient early platelet recovery, nor in a better BM engraftment, nor even very low or absent BM engraftment occurred. In vitro, MSC boosted the migration of CD34(+) cells, suggesting a possible mechanism for the increase in engraftment. Our results show that cotransplantation of MSC with TPO-expanded CD34(+) cells at most combines, but does not increase the separate advantages of these different strategies. A combination of both strategies even adds a risk of non engraftment.

Immunogenetic factors in the selection of cord blood units for transplantation: current search strategies and future perspectives

Hematopoietic stem cell transplantation is currently used as a curative treatment for patients with malignant and non-malignant hematologic diseases. Human leukocyte antigen (HLA) matching is a major determinant for hematopoietic stem cell transplantation outcome. For patients lacking a fully HLA-matched donor, umbilical cord blood (UCB) units are alternative sources of hematopoietic stem cells because UCB transplantation allows a less stringent HLA matching. However, selection of the optimal UCB units remains challenging. The current UCB donor selection strategies are based on both cell dose and HLA matching. This Review focuses on the immunogenetic factors that influence UCB donor selection and highlights the future perspectives in UCB donor search.

Rapid memory T-cell reconstitution recapitulating CD45RA-depleted haploidentical transplant graft content in patients with hematologic malignancies

T-cell depletion of an HLA-haploidentical graft is often used to prevent graft-vs.-host disease (GvHD), but the procedure may lead to increased graft failure, relapse, and infections due to delayed immune recovery. We hypothesized that selective depletion of the CD45RA+ subset can effectively reduce GvHD through removal of naïve T cells, while providing improved donor immune reconstitution through adoptive transfer of CD45RA– memory T cells. Herein, we present results from the first 17 patients with poor-prognosis hematologic malignancy who received haploidentical donor transplantation with CD45RA-depleted progenitor cell grafts following a novel reduced intensity conditioning regimen without total body irradiation or serotherapy. Extensive depletion of CD45RA+ T cells and B cells, with preservation of abundant memory T cells, was consistently achieved in all 17 products. Neutrophil engraftment (median day +10) and full donor chimerism (median day +11) was rapidly achieved post-transplantation. Early T-cell reconstitution directly correlated with the CD45RA-depleted graft content. T-cell function recovered rapidly with broad TCR V_β spectra. There was no infection-related mortality in this heavily pretreated population, and no patient developed acute GvHD despite infusion of a median of >100 million per kilogram haploidentical T cells.

Treatment of relapse of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation

Disease relapse remains a major cause of mortality for patients with acute myeloid leukemia (AML) undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Historically, patients who experience disease relapse after HSCT have a dismal prognosis with very few long-term survivors. There is no standard treatment for patients in this situation given the variability in patient characteristics, disease biology, complications such as graft-vs.-host disease (GVHD) and infections, donor availability, and patient choice. Here, we discuss the current options for treatment of relapsed AML after HSCT including conventional chemotherapy, novel agents, donor leukocyte infusion, second allogeneic HSCT, and emerging therapies.

Recommendations for donor human leukocyte antigen assessment and matching for allogeneic stem cell transplantation: consensus opinion of the Blood and Marrow Transplant Clinical Trials Network (BMT CTN)

The Blood and Marrow Transplant Clinical Trials Network (BMT CTN) conducts large, multi-institutional clinical trials with the goal of improving the outcomes of hematopoietic cell transplantation (HCT) for patients with life-threatening disorders. Well-designed HCT trials benefit from standardized criteria for defining diagnoses, treatment plans, and graft source selection. In this perspective, we summarize evidence supporting criteria for the selection of related and unrelated adult volunteer progenitor cell donors or umbilical cord blood units. These standardized criteria for graft source selection have been adopted by the BMT CTN to enhance the interpretation of clinical findings within and among future clinical protocols.

Comparison of unrelated cord blood and peripheral blood stem cell transplantation in adults with myelodysplastic syndrome after reduced-intensity conditioning regimen: a collaborative study from Eurocord (Cord blood Committee of Cellular Therapy & Immunobiology Working Party of EBMT) and Chronic Malignancies Working Party

Hematopoietic stem cell transplantation (HSCT) remains the only curative treatment in patients with higher risk myelodysplastic syndrome (MDS), but the choice of the optimal alternative stem cell source is still a subject of debate in patients lacking an HLA-matched sibling donor. Here, we report on a large series of patients with MDS (N = 631) transplanted either with mobilized peripheral stem cells (PBs) from unrelated donors (n = 502) or with umbilical cord blood transplant (UCB, n = 129) as alternative grafts after reduced-intensity conditioning. Neutrophil engraftment was higher after PB (98% versus 78%, P < .0001). Acute graft-versus-host disease (GVHD) was similar after PB (31%) and UCB (29%), and chronic GVHD incidence was higher after PB (41% versus 23%). Two-year nonrelapse mortality was lower after PB (31% versus 42% P = .03). There was a better overall survival (OS) and disease-free survival (DFS) after PB (49% ± 2% versus 30% ± 4%, P < .0001 and 44% ± 2% versus 28% ± 4%, P < .0001). Multivariate analysis confirmed the advantage of PB for treatment-related mortality, OS, and DFS, whereas relative risk of chronic GVHD was similar. A multivariate analysis comparing PB from a 10/10 HLA-matched donor, PB from a 9/10 HLA-matched donor, and UCB showed an advantage on treatment-related mortality, DFS, and OS only in 10/10 PB. We conclude that in MDS patients lacking an HLA-matched sibling donor, PB from a 10/10 HLA-matched unrelated donor is the preferred source of hematopoietic stem cells. HLA-mismatched unrelated donor or cord blood seem to give similar inferior results except for neutrophil engraftment, which is delayed after UCB.

Alternative donor transplantation for adults with acute leukemia

Allogeneic hematopoietic cell transplantation (HCT) from a matched related donor (MRD) is the preferred therapy for many adults with acute leukemia. Yet most patients do not have matched siblings, and the numbers who do will continue to drop as the average number of children per couple in the United States continues to decline. Recent reports show little difference in the outcomes of matched related and matched unrelated transplants for acute leukemia. Additionally, survival rates at 3-5 years after transplant appear to be generally similar following matched related, matched unrelated, single antigen mismatched unrelated, double cord blood and, perhaps even after haplo-identical transplants. Nevertheless, there are differences between stem cell sources that should be considered in the choice of donor. The following review provides some perspective on the identification of the best stem cell sources for patients who do not have matches within their families.

Recent advances on cellular therapies and immune modulators for graft-versus-host disease

The efficacy of allogeneic hematopoietic stem cell transplantation is counterbalanced by the occurrence of life-threatening immune-mediated complications, such as graft-versus-host disease (GVHD), a multistep disease which is reportedly fatal to approximately 15% of transplant recipients. It is now established that T-cell-dendritic cell interactions, T-cell activation, release of proinflammatory cytokines and T-cell trafficking partake in GVHD pathogenesis. This article will focus on the most recent strategies aimed at preventing/treating GVHD by manipulating components of the innate and adaptive immune response from both the donor and the host.

Long-term outcome after haploidentical stem cell transplant and infusion of T cells expressing the inducible caspase 9 safety transgene

Adoptive transfer of donor-derived T lymphocytes expressing a safety switch may promote immune reconstitution in patients undergoing haploidentical hematopoietic stem cell transplant (haplo-HSCT) without the risk for uncontrolled graft versus host disease (GvHD). Thus, patients who develop GvHD after infusion of allodepleted donor-derived T cells expressing an inducible human caspase 9 (iC9) had their disease effectively controlled by a single administration of a small-molecule drug (AP1903) that dimerizes and activates the iC9 transgene. We now report the long-term follow-up of 10 patients infused with such safety switch-modified T cells. We find long-term persistence of iC9-modified (iC9-T) T cells in vivo in the absence of emerging oligoclonality and a robust immunologic benefit, mediated initially by the infused cells themselves and subsequently by an apparently accelerated reconstitution of endogenous naive T lymphocytes. As a consequence, these patients have immediate and sustained protection from major pathogens, including cytomegalovirus, adenovirus, BK virus, and Epstein-Barr virus in the absence of acute or chronic GvHD, supporting the beneficial effects of this approach to immune reconstitution after haplo-HSCT. This study was registered at www.clinicaltrials.gov as #NCT00710892.

Design of a cost-effectiveness analysis alongside a randomized trial of transplantation using umbilical cord blood versus HLA-haploidentical related bone marrow in advanced hematologic cancer

BACKGROUND

BMT CTN 1101 is a Phase III randomized controlled trial evaluating the comparative effectiveness of double unrelated umbilical cord blood (dUCB) versus HLA-haploidentical related donor bone marrow (haplo-BM) donor cell sources for blood or bone marrow transplantation (BMT) in patients with hematologic malignancies. Herein, we present the rationale, design and methods of the first cost-effectiveness analysis to be conducted alongside a BMT trial.

METHODS

Consenting patients will provide health insurance information to allow calculation of direct medical costs from reimbursement records, and will provide out-of-pocket costs, time costs and health-related quality of life measures through an online survey. These outcomes will inform a cost-effectiveness analysis comparing dUCB and haplo-BM donor cell sources from patient, payer and societal perspectives.

CONCLUSION

Novel approaches may significantly change the cost, outcomes or availability of BMT. The results of this analysis will be the first to provide a comprehensive evaluation of the comparative effectiveness of these approaches from multiple perspectives.

Long-term immune reconstitution and infection burden after mismatched hematopoietic stem cell transplantation

Mismatched unrelated donor (MMUD) or umbilical cord blood (UCB) can be chosen as alternative donors for allogeneic stem cell transplantation but might be associated with long-lasting immune deficiency. Sixty-six patients who underwent a first transplantation from either UCB (n = 30) or 9/10 MMUD (n = 36) and who survived beyond 3 months were evaluated. Immune reconstitution was prospectively assessed at sequential time points after transplantation. NK, B, CD4(+), and CD8(+) T cells and their naïve and memory subsets, as well as regulatory T cells (Treg), were studied. Detailed analyses on infections occurring after 3 months were also assessed. The 18-month cumulative incidences of infection-related death were 8% and 3%, and of infections were 72% and 57% after MMUD and UCB transplantation, respectively. Rates of infection per 12 patient-month were roughly 2 overall (1 for bacterial, .9 for viral, and .3 for fungal infections). Memory, naïve CD4(+) and CD8(+)T cells, naïve B cells, and Treg cells reconstitution between the 2 sources were roughly similar. Absolute CD4(+)T cells hardly reached 500 per μL by 1 year after transplantation and most B cells were of naïve phenotype. Correlations between immune reconstitution and infection were then performed by multivariate analyses. Low CD4(+) and high CD8(+)T cells absolute counts at 3 months were linked to increased risks of overall and viral (but not bacterial) infections. When assessing for the naïve/memory phenotypes at 3 months among the CD4(+) T cell compartment, higher percentages of memory subsets were protective against late infections. Central memory CD4(+)T cells protected against overall and bacterial infections; late effector memory CD4(+)T cells protected against overall, bacterial, and viral infections. To the contrary, high percentage of effector- and late effector-memory subsets at 3 months among the CD8(+) T cell compartment predicted higher risks for viral infections. Patients who underwent transplantation from alternative donors represent a population with very high risk of infection. Detailed phenotypic analysis of immune reconstitution may help to evaluate infection risk and to adjust infection prophylaxis.

Storage time affects umbilical cord blood viability

BACKGROUND

Cryopreserved umbilical cord blood (CB) is increasingly used as a cell source to reconstitute marrow in hematopoietic stem cell transplant patients. Delays in cryopreservation may adversely affect cell viability, thereby reducing their potential for engraftment after transplantation.

STUDY DESIGN AND METHODS

The impact of delayed cryopreservation for up to 3 days on the viability of both CD45+ and CD34+ cell populations in 28 CB donations with volumes of 58.40 ± 15.4 mL (range, 39.4-107.4 mL) was investigated to establish whether precryopreservation storage time could be extended from our current time of 24 to 48 hours in line with other CB banks. Viability was assessed on 3 consecutive days, both before and after cryopreservation, by flow cytometry using 7-aminoactinomycin D (7-AAD) and annexin V methods.

RESULTS

The results using 7-AAD and annexin V indicated the viability of CD34+ cells before cryopreservation remained high (>92.33 ± 4.11%) over 3 days, whereas the viability of CD45+ cells decreased from 86.36 ± 4.97% to 66.24 ± 7.78% (p < 0.0001) by Day 3. Storage time significantly affected the viability of CD34+ cells after cryopreservation. Using 7-AAD, the mean CD34+ cell viability decreased by approximately 5% per extra day in storage from 84.30 ± 6.27% on Day 1 to 79.01 ± 7.44% (p < 0.0057) on Day 2 and to 73.95 ± 7.54% (p < 0.0001) on Day 3. With annexin V staining CD34+ cell viability fell by approximately 7% per extra day in storage from 77.17 ± 8.47% on Day 1 to 69.56 ± 13.30% (p < 0.0194) on Day 2 and to 62.89 ± 15.22% (p < 0.0002) on Day 3.

CONCLUSION

This study demonstrates that extended precryopreservation storage adversely affects viability and should be avoided.

Frequency of allogeneic hematopoietic cell transplantation among patients with high- or intermediate-risk acute myeloid leukemia in first complete remission

PURPOSE

To determine the frequency of allogeneic hematopoietic cell transplantation (HCT) for patients with acute myeloid leukemia (AML) in first complete remission (CR1).

PATIENTS AND METHODS

Between January 1, 2008, and March 1, 2011, 212 newly diagnosed patients with AML received treatment at our center. Ninety-five patients age less than 75 years with intermediate- or high-risk AML achieved a complete remission, and 21 patients achieved a morphologic remission with incomplete blood count recovery.

RESULTS

Seventy-eight (67%; 95% CI, 58% to 76%) of 116 patients received HCT at a median of 2.8 months (range, 0.5 to 19 months) from their CR1 date. The median age was 57 years in both the HCT patient group (range, 18 to 75 years) and the non-HCT patient group (range, 24 to 70 years; P = .514). Between the HCT patients and the non-HCT patients, the mean Eastern Cooperative Oncology Group performance status was 1.1 compared with 1.5, respectively (P = .005), and the average HCT comorbidity score within 60 days of CR1 was 1.7 and 2.1, respectively (P = .68). Twenty-nine (76%) of 38 non-HCT patients were HLA typed, and matched donors were found for 13 of these 29 patients (34% of all non-HCT patients). The most common causes for patients not receiving transplantation in CR1 were early relapse (within 6 months) in 12 patients (32%), poor performance status in eight patients (21%), and physician decision in five patients (13%).

CONCLUSION

HCT can be performed in CR1 in the majority of patients with AML for whom it is currently recommended. The main barriers to HCT were early relapse and poor performance status, highlighting the need for improved therapies for patients with AML of all ages.

Alternative transplant donor sources: is there any consensus?

PURPOSE OF REVIEW

To review the data supporting the use of alternative donors for hematopoietic cell transplantation of patients with high-risk or advanced hematological malignancies.

RECENT FINDINGS

Advances in supportive therapy and technology have improved the safety and efficacy of alternative donors for hematopoietic cell transplantation. Molecular techniques have allowed for better human leukocyte antigen matching of unrelated adult donors. Novel strategies such as adoptive regulatory T cells or posttransplantation cyclophosphamide contributed to better outcomes after partially matched related donors. In umbilical cord blood transplantation, the ability to find adequately dosed single-unit grafts, the utilization of double-unit grafts, and novel methodologies such as ex-vivo expansion, intrabone injection, and priming to accelerate engraftment are promising. Available retrospective studies suggest despite the differences in hematopoietic recovery, risk of graft-versus-host disease, and relapse, long-term outcomes are similar between different alternative donor types.

SUMMARY

In the absence of a suitable matched related donor, most patients will be able to find an alternative donor to proceed to a potentially curative allogeneic transplantation. Emerging new technologies will further improve the safety and efficacy of alternative donor transplantation. Ongoing and future randomized studies will better define the relative efficacy of alternative donor types.

The impact of HLA unidirectional mismatches on the outcome of myeloablative hematopoietic stem cell transplantation with unrelated donors

The impact of HLA homozygosity at mismatched (MM) loci on the outcome of 2687 myeloablative unrelated donor hematopoietic cell transplantations performed for malignant disease was evaluated among 4 groups: 7/8 bidirectional MM transplants (donor and recipient heterozygous MM, n = 1393), 7/8 host-versus-graft (HVG) vector MM (recipient homozygous, n = 112), 7/8 graft-versus-host (GVH) vector MM (donor homozygous, n = 119), and 8/8 matches (n = 1063). Multivariate analyses found 7/8 GVH (P = .001) and bidirectional MM groups (P < .0001) had significantly worse transplant-related mortality and overall and disease-free survival than the 8/8 match group, a difference not observed with the 7/8 HVG MM group (P > .01). The 3 7/8 groups differed only for grades III-IV acute GVH disease (GVHD), where HVG MM had less GVHD than the 7/8 bidirectional MM (hazard ratio [HR] 0.52, P = .0016) and GVH MM (HR 0.43, P = .0009) groups but not the 8/8 group (HR 0.83, P = .39). There were no differences between the 7/8 groups for relapse, chronic GVHD, neutrophil engraftment, or graft failure. GVH MM have the same risk as 7/8 bidirectional MM. 7/8 HVG MM confer a reduced risk of acute GVHD without an increased risk of disease relapse or graft failure compared with a 7/8 bidirectional MM.

Umbilical cord blood transplantation: the first 25 years and beyond

Umbilical cord blood is an alternative hematopoietic stem cell source for patients with hematologic diseases who can be cured by allogeneic hematopoietic cell transplantation. Initially, umbilical cord blood transplantation was limited to children, given the low cell dose infused. Both related and unrelated cord blood transplants have been performed with high rates of success for a variety of hematologic disorders and metabolic storage diseases in the pediatric setting. The results for adult umbilical cord blood transplantation have improved, with greater emphasis on cord blood units of sufficient cell dose and human leukocyte antigen match and with the use of double umbilical cord blood units and improved supportive care techniques. Cord blood expansion trials have recently shown improvement in time to engraftment. Umbilical cord blood is being compared with other graft sources in both retrospective and prospective trials. The growth of the field over the last 25 years and the plans for future exploration are discussed.

Umbilical cord blood transplantation: review of factors affecting the hospitalized patient

The use of umbilical cord blood (UCB) as a stem cell donor source has dramatically increased over the last 2 decades. Patients undergoing UCB transplantation share medical management issues with patients receiving a hematopoietic stem cell transplantion using adult donor sources (peripheral blood stem cells or bone marrow stem cells) and may also have more complex medical issues that appear to be related to delayed immune recovery from UCB-derived stem cells. The interface with critical care providers is likely to occur in the transplant and posttransplant setting. Patients may experience UCB infusion reactions that range from mild to rarely severe. Following transplant, patients are transfusion dependent for long periods due to the prolonged engraftment of UCB cells. They are at high risk of infection, particularly viral. Once engrafted, UCB transplant patients have a lower rate of graft versus host disease compared to other donor sources. Some of the other complications that are seen in patients undergoing UCB transplant are posttransplant lymphoproliferative disease, diffuse alveolar hemorrhage, and posterior reversible encephalopathy will also be discussed.

Human leukocyte antigen-haploidentical stem cell transplantation using T-cell-replete bone marrow grafts

PURPOSE OF REVIEW

Once considered too dangerous for all but the sickest of patients, partially human leukocyte antigen (HLA)-mismatched, or HLA-haploidentical, related donor bone marrow transplantation (haploBMT) has seen a revival, thanks to the reduced intensity conditioning (RIC) regimens and graft-versus-host disease (GVHD) prophylaxis with high-dose posttransplantation cyclophosphamide (PT/Cy).

RECENT FINDINGS

RIC haploBMT with high-dose PT/Cy is associated with a cumulative incidence of acute grades II-IV GVHD of approximately 30% and incidences of chronic GVHD and nonrelapse mortality (NRM) less than 15%. These results have been confirmed in single and multicenter clinical trials. PT/Cy appears to nullify the detrimental effects of HLA mismatching on the outcome of haploBMT, thereby permitting the selection of haplo donors based upon criteria other than HLA matching. Overall and event-free survivals of RIC haploBMT compare favorably to the outcomes of RIC unrelated adult donor or umbilical cord blood stem cell transplantation.

SUMMARY

With its improved toxicity profile, haploBMT is a feasible alternative for patients who lack an HLA-matched donor and can now be applied to treat patients with nonmalignant disorders.

Granulocyte-mobilized bone marrow

PURPOSE OF REVIEW

In the last few years, mobilized peripheral blood has overcome bone marrow as a graft source, but, despite the evidence of a more rapid engraftment, the incidence of chronic graft-versus-host disease is significantly higher with, consequently, more transplant-related mortality on the long follow-up. Overall, the posttransplant outcome of mobilized peripheral blood recipients is similar to that of patients who are bone marrow grafted. More recently, the use of bone marrow after granulocyte colony-stimulating factor (G-CSF) donor priming has been introduced in the transplant practice. Herein, we review biological acquisitions and clinical results on the use of G-CSF-primed bone marrow as a source of hematopoietic stem cells (HSC) for allogeneic stem cell transplantation.

RECENT FINDINGS

G-CSF the increases the HSC compartment and exerts an intense immunoregulatory effect on marrow T-cells resulting in the shift from Th1 to Th2 phenotype with higher production of anti-inflammatory cytokines. The potential advantages of these biological effects have been translated in the clinical practice by using G-CSF primed unmanipulated bone marrow in the setting of transplant from human leukocyte antigen (HLA)-haploidentical donor with highly encouraging results.

SUMMARY

For patients lacking an HLA-identical sibling, the transplant of G-CSF primed unmanipulated bone marrow from a haploidentical donor combined with an intense in-vivo immunosuppression is a valid alternative achieving results that are well comparable with those reported for umbilical cord blood, HLA-matched unrelated peripheral blood/bone marrow or T-cell-depleted haploidentical transplant.

Umbilical cord blood transplantation supported by third-party donor cells: rationale, results, and applications

Low incidence of graft-versus-host disease provides the major rational for pursuing umbilical cord blood (UCB) stem cell transplantation (SCT). Considerable evidence also suggests a lower rate of recurrence after UCB SCT than after transplantation from adult donors. Recent advances in understanding of the human fetal immune development provide a rational underpinning for these clinical outcomes. The fetal immune system is geared toward maintaining tolerance to foreign antigens, particularly to the maternal antigens to which it is exposed throughout gestation. To this purpose it is dominated by a unique population of peripheral T regulatory cells that actively maintain tolerance. This and other features of the UCB lymphoid system explains the low incidence of graft-versus-host disease and superior outcomes of UCB SCT with noninherited maternal antigen-matched grafts. At the same time, highly sensitized maternal microchimeric cells are frequently detected in UCB and likely contribute to superior graft-versus-leukemia effects and low rates of disease recurrence in inherited paternal antigen-matched UCB recipients. However, historically erratic and slow hematopoietic recovery after UCB SCT leads to increased early morbidity and mortality, excessive hospitalization, and increased costs. This has held up the widespread utilization of UCB SCT in adults. Here we summarize recent data on UCB SCT with an emphasis on studies of co-infusion of adult CD34 selected hematopoietic stem cells with UCB SCT. This procedure, through transient engraftment of adult hematopoietic stem cells, largely overcomes the problem of delayed engraftment. It also results in predictable engraftment of a UCB with the desired characteristics. We also briefly discuss unresolved issues and possible future applications of this technology.

Selective T-cell depletion for haplotype-mismatched allogeneic stem cell transplantation

Haplotype-mismatched transplantation offers a unique opportunity to treat patients without a suitable matched related or unrelated donor. Indeed, related haplo-donors are usually extremely motivated, immediately available, and can provide additional stem or immune cells when required, a most important feature in the context of high-risk malignancies. Immunomagneticallly selected CD34(+) stem cell grafts enable rapid and sustained trilineage engraftment. However, the associated delay in immune reconstitution results in significant risk for severe infectious complications and malignant relapse. The infusion of T lymphocytes selectively depleted of their anti-host reactive components represents a most interesting approach to accelerate post-transplant T-cell recovery. Such a strategy relies on ex vivo donor cell activation against host antigens and their selective elimination. Immunotoxins and magnetic beads could target antigens such as CD25 with impressive results. Photodepletion of alloreactive T cells represents an appealing alternative to both eliminate anti-host immune T cells and spare resting T cells to fight infections. Interestingly, regulatory T cells can be retained after such treatment, and have been found to transform non-regulatory into regulatory T cells, a finding that may be of utmost importance in both prevention and control of graft-versus-host disease (GVHD). Efforts to promote efficient antigen presentation and selective allodepletion promise to accelerate immune reconstitution without GVHD and to address the most crucial issues in haplo-mismatched and other types of transplants.

Immune reconstitution after combined haploidentical and umbilical cord blood transplant

Umbilical cord blood (UCB) stem cells are frequently employed for allogeneic stem cell transplant, but delayed myeloid and lymphoid immune reconstitution leads to increased risk of infections. We recently reported the clinical results of 45 patients enrolled on a pilot study combining UCB with a human leukocyte antigen (HLA)-haploidentical donor with reduced-intensity conditioning who showed rapid neutrophil and platelet recovery. We report here preliminary immune reconstitution data of these patients. Patients were assessed for lymphocyte subsets, T-cell diversity, Cylex ImmuKnow assay and serological response to pneumococcal vaccination. Natural killer (NK)-cell and B-cell reconstitution were rapid at 1 month and 3 months, respectively. T-cell recovery was delayed, with a gradual increase in the number of T-cells starting around 6 months post-transplant, and was characterized by a diverse polyclonal T-cell repertoire. Overall, immune reconstitution after haplo-cord transplant is similar to that seen after cord blood transplant, despite infusion of much lower cord blood cell dose.

Mesenchymal stem cells as cellular immunotherapeutics in allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment option in hematopoietic disorders, immunodeficiencies and leukemia. To date graft-versus-host disease (GvHD) represents a life-threatening complication even if associated with beneficial antileukemic reactivity. GvHD is the clinical manifestation of donor cells reacting against host tissue. Because of their ability to facilitate endogenous repair and to attenuate inflammation, MSC have evolved as a highly attractive cellular therapeutic in allo-HSCT. Here we report on the clinical experience in the use of MSC to enhance engraftment and prevent and treat acute and chronic GvHD. In early clinical trials, MSC have shown considerable benefit in the setting of manifest GvHD. These encouraging results warrant further exploration.