Cord blood transplantation for haematological malignancies: conditioning regimens, double cord transplant and infectious complications

Single vs double umbilical cord blood transplantation in acute leukemia: Systematic review and meta-analysis

BACKGROUND AND AIMS

Umbilical cord blood transplantation (UCBT) has emerged as a promising treatment option for patients with acute leukemia needing hematopoietic stem cell transplantation. Both single (sUCBT) and double cord blood units (dUCBT) demonstrate potential benefits, but studies comparing their effectiveness have shown mixed results. This meta-analysis aimed to determine the comparative safety and efficacy of sUCBT versus dUCBT in acute leukemia patients.

METHODS

Electronic databases were systematically examined to identify relevant studies comparing single vs double UCBT published until November 2023. Nine studies involving 3864 acute leukemia patients undergoing UCBT were included. Outcomes analyzed were acute graft-versus-host disease (GVHD), chronic GVHD, relapse, non-relapse mortality, leukemia-free survival and overall survival. Pooled risk ratios (RR) with 95% confidence intervals (CI) were calculated using a random effects model.

RESULTS

The risk of Grade II-IV acute GVHD (RR 1.55, 95% CI 1.19-2.03) and Grade III-IV acute GVHD (RR 1.25, 95% CI 1.07-1.46) were significantly higher with dUCBT. Relapse risk was lower with dUCBT (RR 0.57, 95% CI 0.38-0.88) while overall survival favored sUCBT (RR 1.25, 95% CI 1.06-1.46). No significant differences were observed for chronic GVHD, non-relapse mortality or leukemia-free survival.

CONCLUSION

Both single and double UCBT have potential as effective treatments for acute leukemia. The choice of treatment should consider various factors, including the risk of GVHD, relapse, and mortality. More research, especially randomized trials, is needed to provide definitive guidance on the optimal use of single and double unit UCBT in patients with acute leukemia.

Graft versus Leukemia in 2023

Allogeneic hematopoietic stem cell transplantation (HSCT) is commonly utilized in the management of leukemia across multiple subtypes. Graft versus leukemia (GVL) is a critical component of successful transplantation and involves donor cells eradicating residual leukemia within the recipient. Graft versus host disease (GVHD) by contrast is a common complication of the transplantation process in which donor cells identify the recipient's various organ systems as foreign, thereby leading to a multitude of organ toxicities that can be described as autoimmune in nature. As both GVL and GVHD are mediated by a similar mechanism, these processes are felt to occur in tandem with one another. Here, we review the allogeneic HCT process in the context of GVL.

Potential Therapeutic Role of Mesenchymal-Derived Stem Cells as an Alternative Therapy to Combat COVID-19 through Cytokines Storm

Medical health systems continue to be challenged due to newly emerging COVID-19, and there is an urgent need for alternative approaches for treatment. An increasing number of clinical observations indicate cytokine storms to be associated with COVID-19 severity and also to be a significant cause of death among COVID-19 patients. Cytokine storm involves the extensive proliferative and hyperactive activity of T and macrophage cells and the overproduction of pro-inflammatory cytokines. Stem cells are the type of cell having self-renewal properties and giving rise to differentiated cells. Currently, stem cell therapy is an exciting and promising therapeutic approach that can treat several diseases that were considered incurable in the past. It may be possible to develop novel methods to treat various diseases by identifying stem cells’ growth and differentiation factors. Treatment with mesenchymal stem cells (MSCs) in medicine is anticipated to be highly effective. The present review article is organized to put forward the positive arguments and implications in support of mesenchymal stem cell therapy as an alternative therapy to cytokine storms, to combat COVID-19. Using the immunomodulatory potential of the MSCs, it is possible to fight against COVID-19 and counterbalance the cytokine storm.

T-cell depleted haploidentical hematopoietic cell transplantation for pediatric malignancy

Access to allogenic hematopoietic cell transplantation (HCT), a potentially curative treatment for chemotherapy-resistant hematologic malignancies, can be limited if no human leukocyte antigen (HLA) identical related or unrelated donor is available. Alternative donors include Cord Blood as well as HLA-mismatched unrelated or related donors. If the goal is to minimize the number of HLA disparities, partially matched unrelated donors are more likely to share 8 or 9 of 10 HLA alleles with the recipient. However, over the last decade, there has been success with haploidentical HCT performed using the stem cells from HLA half-matched related donors. As the majority of patients have at least one eligible and motivated haploidentical donor, recruitment of haploidentical related donors is frequently more rapid than of unrelated donors. This advantage in the accessibility has historically been offset by the increased risks of graft rejection, graft-versus-host disease and delayed immune reconstitution. Various ex vivo T-cell depletion (TCD) methods have been investigated to overcome the immunological barrier and facilitate immune reconstitution after a haploidentical HCT. This review summarizes historical and contemporary clinical trials of haploidentical TCD-HCT, mainly in pediatric malignancy, and describes the evolution of these approaches with a focus on serial improvements in the kinetics of immune reconstitution. Methods of TCD discussed include in vivo as well as ex vivo positive and negative selection. In addition, haploidentical TCD as a platform for post-HCT cellular therapies is discussed. The present review highlights that, as a result of the remarkable progress over half a century, haploidentical TCD-HCT can now be considered as a preferred alternative donor option for children with hematological malignancy in need of allogeneic HCT.

Conditioning with 10 Gy Total Body Irradiation, Cyclophosphamide, and Fludarabine without ATG Is Associated with Improved Outcome of Cord Blood Transplantation in Children with Acute Leukemia

BACKGROUND

The optimal conditioning regimen in cord blood transplantation (CBT) needs to be determined. This study aimed to identify the impact of conditioning regimen on the outcome of CBT in children with acute leukemia.

METHODS

Medical records of patients with acute leukemia who received CBT were retrospectively reviewed.

RESULTS

A total of 71 patients were allocated into 2 groups; patients who received total body irradiation 10 Gy, cyclophosphamide 120 mg/kg, and fludarabine 75 mg/m² were named as TCF group (n = 18), while the non-TCF group (n = 53) included patients conditioned with regimens other than the TCF regimen. All patients in the TCF group were successfully engrafted, while 22.6% in the non-TCF group (n = 12) failed to achieve donor-origin hematopoiesis (P = 0.028). The incidence of cytomegalovirus diseases was 5.6% in the TCF group and 30.2% in the non-TCF group (P = 0.029). The 5-year overall survival rates of the TCF and non-TCF groups were 77.8% and 44.2%, respectively (P = 0.017).

CONCLUSION

Patients conditioned with the TCF regimen achieved better engraftment and survival rates, less suffering from cytomegalovirus disease. Our data suggest that the TCF regimen is a preferred option for CBT in children with acute leukemia.

Meta-analysis of hematopoietic stem cell transplantation in major histocompatibility complex class II deficiency

Major histocompatibility complex class II deficiency is a rare case of PID. Specific recommendations for hematopoietic stem cell transplant, the only curative treatment option, are still lacking. This meta-analysis aims to identify the factors associated with better prognosis in these patients. Thirteen articles reporting 63 patients with major histocompatibility complex class II deficiency that underwent hematopoietic stem cell transplant were included. The median age for hematopoietic stem cell transplant was 18 months. The most common source of transplant was bone marrow, with alternative sources as umbilical cord blood emerging during recent years. The highest proportion of engraftment was seen with umbilical cord. Engraftment was higher in patients with matched donors, with better overall survival in patients with reduced-intensity conditioning. Graft-vs-host disease developed in 65% of the patients, with grades I-II being the most frequently encountered. There was a higher mortality in patients with myeloablative conditioning and no engraftment. There was an inverse correlation between survival and stage of graft-vs-host disease. The main cause of mortality was infectious disease, mostly secondary to viral infections. Ideally, matched grafts should be used, and reduced-intensity conditioning should be considered to reduce early post-transplant complications. GVHD and viral prophylaxis are fundamental.

Targeting the Spleen as an Alternative Site for Hematopoiesis

Bone marrow is the main site for hematopoiesis in adults. It acts as a niche for hematopoietic stem cells (HSCs) and contains non-hematopoietic cells that contribute to stem cell dormancy, quiescence, self-renewal, and differentiation. HSC also exist in resting spleen of several species, although their contribution to hematopoiesis under steady-state conditions is unknown. The spleen can however undergo extramedullary hematopoiesis (EMH) triggered by physiological stress or disease. With the loss of bone marrow niches in aging and disease, the spleen as an alternative tissue site for hematopoiesis is an important consideration for future therapy, particularly during HSC transplantation. In terms of harnessing the spleen as a site for hematopoiesis, here the remarkable regenerative capacity of the spleen is considered with a view to forming additional or ectopic spleen tissue through cell engraftment. Studies in mice indicate the potential for such grafts to support the influx of hematopoietic cells leading to the development of normal spleen architecture. An important goal will be the formation of functional ectopic spleen tissue as an aid to hematopoietic recovery following clinical treatments that impact bone marrow. For example, expansion or replacement of niches could be considered where myeloablation ahead of HSC transplantation compromises treatment outcomes.

Retrospective cohort study comparing the outcomes of intravenous busulfan vs. total-body irradiation after single cord blood transplantation

Limited to inadequate stem-cell doses, cord blood transplantation (UCBT) is accompanied by increased graft failure and delayed haematopoietic recovery. The conditioning regimen is critically important for engraftment, and numerous trials have been undertaken comparing the outcomes of IV Bu and TBI, but there are no comparative data for UCBT. We conducted a retrospective multicentre study to analyse the outcomes of IV Bu and TBI in UCBT patients with haematologic malignancies. Between 1 May, 2008 and 31 Mar, 31 2018, a total of 331 patients from the China Umbilical Cord Blood Transplantation Corporation (IV Bu, n = 131; TBI, n = 200) were evaluated. The cumulative incidence of neutrophil engraftment was 91.6% in the IV Bu/Cy cohort and 98.0% in the Cy/TBI cohort (P < 0.001). The median times to neutrophil engraftment were 16 and 19 days (P < 0.001), respectively. Multivariate analysis showed no statistical difference for nonrelapse mortality (hazard ratio [HR], 1.11; 95% confidence interval [CI], 0.66 to 1.86; P = 0.695), relapse (HR, 0.90; 95% CI, 0.50 to 1.60; P = 0.713) and overall survival (HR, 0.94; 95% CI, 0.61 to 1.44; P = 0.763) between the two conditioning regimens. Our results show that both IV Bu and TBI are valid myeloablative conditioning regimens for haematologic malignancy patients treated with UCBT.

Cohort-Controlled Comparison of Umbilical Cord Blood Transplantation Using Carlecortemcel-L, a Single Progenitor-Enriched Cord Blood, to Double Cord Blood Unit Transplantation

Umbilical cord blood (UCB) transplantation has a high early mortality rate primarily related to transplanted stem cell dose. To decrease early mortality and enhance engraftment, a portion of selected cord blood units (20% to 50%) was expanded with cytokines and the copper chelator tetraethylenepentamine (carlecortemcel-L) and transplanted with the unmanipulated fraction after myeloablative conditioning. The primary endpoint was 100-day survival, which was compared with a contemporaneous double-unit cord blood transplantation (DUCBT) group. We enrolled 101 patients at 25 sites; the DUCBT comparison (n = 295) was selected from international registries using study eligibility criteria. Baseline carlecortemcel-L study group unit nucleated cell (NC) and CD34⁺ were 3.06 × 10⁷ cell dose/kg and 1.64 × 10⁵ cell dose/kg. Median NC and CD34⁺ fold expansion were 400 and 77, with a mean total CD34 infused of 9.7 × 10⁵/kg. The 100-day survival was 84.2% for the carlecortemcel-L study group versus 74.6% for the DUCBT group (odds ratio, .50; 95% CI, .26 to .95; P = .035). Survival at day 180 was similar for the 2 groups; the major cause of death after day 100 was opportunistic infections. Faster median neutrophil (21 days versus 28 days; P < .0001), and platelet (54 days versus 105 days; P = .008) engraftment was seen in the carlecortemcel-L study group; acute and chronic graft-versus-host disease rates were similar. In this multinational comparative study, transplanting expanded CD34⁺ stem cells from a portion of a single UCB unit, with the remaining unmanipulated fraction improved 100-day survival compared with DUCBT control patients while facilitating myeloid and platelet engraftment. This trial was registered at www.clinicaltrials.gov as #NCT00469729.

Haematopoietic stem cells: past, present and future

The discovery and characterisation of haematopoietic stem cells has required decades of research. The identification of adult bone marrow as a source of haematopoietic cells capable of protecting an organism from otherwise lethal irradiation led to the intense search for their identity and characteristics. Using functional assays along with evolving techniques for isolation of haematopoietic cells, haematopoietic stem cell populations were able to be enriched and their characteristics analysed. The key haematopoietic stem cell characteristics of pluripotentiality and the ability for self-renewal have emerged as characteristics of several haematopoietic stem cell populations, including those that have recently challenged the conventional concepts of the haematopoietic hierarchy. Human allogeneic stem cell therapy relies on these functional characteristics of haematopoietic stem cells that can be isolated from peripheral blood, bone marrow or cord blood, with the additional requirement that immunological barriers need to be overcome to allow sustained engraftment while minimising risk of graft-versus-host disease developing in the recipient of transplanted stem cells. Current and future research will continue to focus on the identification of haematopoietic stem cell regulators and methods for in vitro and in vivo stem cell manipulation, including genome editing, to expand the scope, potential and safety of therapy using haematopoietic stem cells.

CD4+ T-cell alloreactivity toward mismatched HLA class II alleles early after double umbilical cord blood transplantation

Although double umbilical cord blood transplantation (dUCBT) in adult patients may be associated with less graft failure compared with single UCBT, hematopoietic recovery generally originates from a single cord blood unit (CBU). CBU predominance is still incompletely understood. We recently showed that blood CD4⁺ T-cell numbers rapidly increase after dUCBT, and early CD4⁺ T-cell chimerism predicts for graft predominance. Given the frequent HLA class II allele mismatches between CBUs in dUCBT, we hypothesized that alloreactive HLA class II-specific CD4⁺ T cells from the "winning" CBU may contribute to rejection of the "loser" CBU. We evaluated whether CD4⁺ T cells originating from the predominant (PD)-CBU would recognize HLA class II allele mismatches, expressed by the nonengrafting (NE)-CBU. Alloreactive effector CD4⁺ T cells toward 1 or more mismatched HLA class II alleles of the NE-CBU were detected in 11 of 11 patients, with reactivity toward 29 of 33 (88%) tested mismatches, and the strongest reactivity toward DR and DQ alleles early after dUCBT. Mismatched HLA class II allele-specific CD4⁺ T cells recognized primary leukemic cells when the mismatched HLA class II allele was shared between NE-CBU and patient. Our results suggest that cytotoxicity exerted by CD4⁺ T cells from the PD-CBU drives the rapid rejection of the NE-CBU, whose alloreactive effect might also contribute to graft-versus-leukemia.

Severe infections after single umbilical cord blood transplantation in adults with or without the co-infusion of CD34+ cells from a third-party donor: results of a multicenter study from the Grupo Español de Trasplante Hematopoyético (GETH)

BACKGROUND

Umbilical cord blood transplantation (CBT) is an established alternative source of stem cells in the setting of unrelated transplantation. When compared with other sources, single-unit CBT (sCBT) is associated with a delayed hematologic recovery, which may lead to a higher infection-related mortality (IRM). Co-infusion with the sCBT of CD34+ peripheral blood stem cells from a third-party donor (TPD) (sCBT + TPDCD34+) has been shown to markedly accelerate leukocyte recovery, potentially reducing the IRM. However, to our knowledge, no comparative studies have focused on severe infections and IRM with these 2 sCBT strategies.

METHODS

A total of 148 consecutive sCBT (2000-2010, median follow-up 4.5 years) were included in a multicenter retrospective study to analyze the incidence and risk factors of IRM and severe viral and invasive fungal infections (IFIs). Neutrophil engraftment occurred in 90% of sCBT (n = 77) and 94% sCBT + TPDCD34+ (n = 71) recipients at a median of 23 and 12 days post transplantation, respectively (P < 0.01).

RESULTS

The 4-year IRM was 24% and 20%, respectively (P = 0.7), with no differences at day +30 (5% and 4%, respectively) and day +100 (10% and 8%, respectively). In multivariate analysis early status of the underlying malignancy, cytomegalovirus (CMV)-seronegative recipient and high CD34+ cell content in the cord blood unit before cryostorage (≥1.4 × 10(5) /kg) were protective of IRM. Among the causes of IRM, bacterial infections and IFIs were more common in sCBT (15% vs. 4%), while CMV disease and parasitic infections were more common in the sCBT + TPDCD34+ cohort (5% vs. 16%).

CONCLUSION

These data show that sCBT supported with TPDCD34(+) cells results in much shorter periods of post-transplant leukopenia, but the short- and long-term rates of IRM were comparable to those of sCBT, presumably because immune recovery is equally delayed in both graft types.

Discovery of novel INK4C small-molecule inhibitors to promote human and murine hematopoietic stem cell ex vivo expansion

Hematopoietic stem cells (HSCs) have emerged as promising therapeutic cell sources for high-risk hematological malignancies and immune disorders. However, their clinical use is limited by the inability to expand these cells ex vivo. Therefore, there is an urgent need to identify specific targets and effective probes that can expand HSCs. Here we report a novel class of INK4C (p18^INK4C or p18) small molecule inhibitors (p18SMIs), which were initially found by in silico 3D screening. We identified a lead p18 inhibitor, XIE18-6, confirmed its p18-targeting specificity and bioactivity of promoting HSCs expansion, and then performed structure-activity relationship (SAR) studies by synthesizing a series of analogs of XIE18–6. Among these, compound 40 showed the most potent bioactivity in HSCs expansion (ED₅₀ = 5.21 nM). We confirmed that compound 40 promoted expansion of both murine and human HSCs, and also confirmed its p18-targeting specificity. Notably, compound 40 did not show significant cytotoxicity toward 32D cells or HSCs, nor did it augment leukemia cell proliferation. Taken together, our newly discovered p18SMIs represent novel chemical agents for murine and human HSCs ex vivo expansion and also can be used as valuable chemical probes for further HSC biology research towards promising utility for therapeutic purposes.

Cord blood processing by a novel filtration system

Objectives

Availability of cord blood (CB) processing has been limited by the need for electrically aided centrifugal techniques, which often produce only low final cell product yield. Here, we describe development and characterization of a novel filter device aimed at allowing CB processing, using gentle gravity‐led flow.

Materials and methods

CB was processed with a novel filter device (CellEffic CB, consisting of non‐woven fabric), without any centrifugation. Cells were harvested by flushing the filter with either HES or physiological saline solution (SALINE). Differential cell counts and viability analysis, combined with Fluorescence‐Activated Cell Sorting (FACS) (total nucleated cells [TNC], mononuclear cells [MNC], CD45+ CD34+ cells, hematopoietic precursor cells [HPCs]) and clonogenic assay, were employed for analysis of CB pre‐ and post‐processing, and after freeze/thawing.

Results

Processing using the novel filter yielded high quality RBC depletion while maintaining good recovery of TNC, MNC, CD34+, HPCs and colony forming unit (CFU) output. The filter performed equally well using HES or SALINE. Gravity‐led flow provided gentle cell movement and protection of the stem cell compartment. Post‐thaw CFU output was maintained particularly, an important indicator for CB banking.

Conclusions

Geographical limitations of CB transplantation and banking have required a non‐electrical, non‐centrifugal solution. This novel filter CellEffic CB device revealed rapid yet gentle cell processing while maintaining the stem/progenitor cell compartment required for both haematological and regenerative medicine therapies.

Results of a prospective multicentre myeloablative double-unit cord blood transplantation trial in adult patients with acute leukaemia and myelodysplasia

Double-unit cord blood (CB) grafts may improve engraftment and relapse risk in adults with haematological malignancies. We performed a prospective high-dose myeloablative double-unit CB transplantation (CBT) trial in adults with high-risk acute leukaemia or myelodysplasia (MDS) between 2007 and 2011. The primary aim was to establish the 1-year overall survival in a multi-centre setting. Fifty-six patients (31 acute myeloid leukaemia, 19 acute lymphoblastic leukaemia, 4 other acute leukaemias, 2 myelodysplastic syndrome [MDS]) were transplanted at 10 centres. The median infused total nucleated cell doses were 2·62 (larger unit) and 2·02 (smaller unit) x 10(7) /kg. The cumulative incidence of day 100 neutrophil engraftment was 89% (95% confidence interval [CI]: 80-96). Day 180 grade II-IV acute graft-versus-host disease (GVHD) incidence was 64% (95%CI: 51-76) and 36% (95%CI: 24-49) of patients had chronic GVHD by 3-years. At 3-years post-transplant, the transplant-related mortality (TRM) was 39% (95%CI: 26-52), and the 3-year relapse incidence was 11% (95%CI: 4-21). With a median 37-month (range 23-71) follow-up of survivors, the 3-year disease-free survival was 50% (95%CI: 37-63). Double-unit CBT is a viable alternative therapy for high-risk acute leukaemia/ MDS in patients lacking a matched unrelated donor. This is especially important for minority patients. The relapse incidence was low but strategies to ameliorate TRM are needed.

Double umbilical cord blood transplantation: relevance of persistent mixed-unit chimerism

Double umbilical cord blood transplantation (UCBT) was developed as a strategy to circumvent the cell dose limitation of single UCBT with a concomitant potential benefit of lowering the rate of leukemia relapse. Sustained hematopoiesis after double UCBT usually is derived from a single donor unit, as only a few patients have been reported to display stable mixed-unit chimerism for varying periods of time. Explanations for the 1 unit dominance, predictors for identifying unit superiority, and persistence of long-term mixed-unit chimerism remain elusive. Review of published literature revealed only 11 of 280 patients (4%) with mixed-unit chimerism for at least 1 year after transplantation, with 3 patients receiving reduced-intensity conditioning regimens. Mixed-unit chimerism was more likely if both units were closely HLA matched to each other. Outcome data for patients with stable mixed-unit chimerism, for the most part, were scarcely reported. Analysis of the small sample size revealed a potential advantage of stable mixed-unit chimerism on enhancing the graft-versus-leukemia effect; however, definitive conclusions cannot be made on the effect of mixed-unit chimerism on the rates of graft-versus-host disease. Therefore, gathering outcome data prospectively in larger clinical series will help answer the question of whether stable mixed-unit chimerism is either beneficial and, therefore, should be strived for, detrimental and, thus, needs to be eliminated, or if it is of no clinical consequence.

Triple opportunistic pulmonary cavitary disease after cord blood transplantation

Opportunistic infectious diseases in patients are variable and depend on the host as well as the type of immunosuppression. Cord blood transplant recipients appear to be particularly vulnerable to infectious complications. Sequential or concurrent opportunistic infectious diseases can be particularly difficult to manage and have increased mortality. We present a young patient, status post cord blood transplantation for acute myelogenous leukemia, who developed a large pulmonary mass-like infection with Aspergillus, cytomegalovirus, and Mycobacterium avium complex. Radiological, surgical, and pathological features are described.

Graft-versus-host disease and survival after cord blood transplantation for acute leukemia: a comparison of Japanese versus White populations

An earlier report identified higher risks of acute and chronic graft-versus-host disease (GVHD) in White children compared with the Japanese after HLA-matched sibling transplantations. The current analysis explored whether racial differences are associated with GVHD risks after unrelated umbilical cord blood transplantation. Included are patients of Japanese descent (n = 257) and Whites (n = 260; 168 of 260 received antithymocyte globulin [ATG]). Transplants were performed in the United States or Japan between 2000 and 2009; patients were aged 16 years or younger, had acute leukemia, were in complete remission, and received a myeloablative conditioning regimen. The median ages of the Japanese and Whites who received ATG were younger at 5 years compared with 8 years for Whites who did not receive ATG. In all groups most transplants were mismatched at 1 or 2 HLA loci. Multivariate analysis found no differences in risks of acute GVHD between the Japanese and Whites. However, chronic GVHD was higher in Whites who did not receive ATG compared with the Japanese (hazard ratio, 2.16; P < .001), and treatment-related mortality was higher in Whites who received ATG compared with the Japanese (relative risk, 1.81; P = .01). Nevertheless, there were no significant differences in overall survival between the 3 groups.

Impact of allele-level HLA matching on outcomes after myeloablative single unit umbilical cord blood transplantation for hematologic malignancy

We studied the effect of allele-level matching at human leukocyte antigen (HLA)-A, -B, -C, and -DRB1 in 1568 single umbilical cord blood (UCB) transplantations for hematologic malignancy. The primary end point was nonrelapse mortality (NRM). Only 7% of units were allele matched at HLA-A, -B, -C, and -DRB1; 15% were mismatched at 1, 26% at 2, 30% at 3, 16% at 4, and 5% at 5 alleles. In a subset, allele-level HLA match was assigned using imputation; concordance between HLA-match assignment and outcome correlation was confirmed between the actual and imputed HLA-match groups. Compared with HLA-matched units, neutrophil recovery was lower with mismatches at 3, 4, or 5, but not 1 or 2 alleles. NRM was higher with units mismatched at 1, 2, 3, 4, or 5 alleles compared with HLA-matched units. The observed effects are independent of cell dose and patient age. These data support allele-level HLA matching in the selection of single UCB units.

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.

A novel reduced-intensity conditioning regimen induces a high incidence of sustained donor-derived neutrophil and platelet engraftment after double-unit cord blood transplantation

A preparative regimen of reduced intensity that can reliably engraft cord blood (CB) and can be used as an alternative to either high-dose myeloablative or nonmyeloablative conditioning is needed. We evaluated double-unit CB transplantation in 30 patients (median age, 56 years; range, 18 to 69) with acute leukemia or myelodysplasia using a regimen of cyclophosphamide 50 mg/kg, fludarabine 150 mg/m(2), thiotepa 10 mg/kg, and 400 cGy total body irradiation with cyclosporine-A/mycophenolate mofetil immunosuppression. Ninety-seven percent of patients engrafted at a median of 26 days (range, 13 to 43), and 93% of patients had recovered platelets by day 180. Grades II to IV acute graft-versus-host disease (GVHD) incidence was 67% at day 180, and chronic GVHD was 10% at 1 year. Transplant-related mortality was 20% at day 180, and relapse was 11% at 2 years. Overall, 2-year disease-free survival (DFS) was 60% at 2 years. A hierarchy in DFS was seen according to the Sorror comorbidity score: 11 patients (median age, 55 years) with a score of 1 had a 2-year DFS of 82% compared with 62% in 9 patients (median age, 51 years) with a score of 2 to 3 and 40% in 11 patients (median age, 58 years) with a score of 4 to 5 (P = .13). This reduced-intensity regimen combined with double-unit CB transplantation reliably facilitates sustained donor engraftment without antithymocyte globulin. Although other approaches are needed in patients with high comorbidity scores, this regimen is highly effective in patients ≥50 years old who are otherwise reasonably fit. It also represents a promising alternative to high-dose conditioning in younger patients.

Double unit grafts successfully extend the application of umbilical cord blood transplantation in adults with acute leukemia

Cell dose is a major limitation for umbilical cord blood (UCB) transplantation because units containing a minimum of 2.5 x 10(7) total nucleated cells (TNC)/kilogram patient body weight are frequently not available. The transplantation of 2 partially HLA-matched UCB units has been adopted as a simple approach for increasing the TNC.We sought to determine whether the relative safety and efficacy of this approach was comparable with a single UCB transplantation. Included are adults with acute leukemia who received transplants with 1 (n =106) or 2 (n =303) UCB units. All UCB units for single UCB transplantations contained TNC ≥ 2.5 x 10(7)/kg. For double UCB transplantations, the total TNC for units 1 and 2 were > 2.5 x 10(7)/kg but in approximately half of these transplantations, 1 of the 2 units contained < 2.5 x 10(7) TNC/kg. Adjusting for factors associated with outcomes, risks of neutrophil recovery (odds ratio 0.83, P =.59), transplantation-related mortality (hazard ratio [HR] 0.91, P= .63), relapse (HR 0.90, P= .64), and overall mortality (HR 0.93, P= .62) was similar after double UCB and adequate dose single UCB transplantations. These data support double UCB unit transplantation for acute leukemia when an adequately dosed single UCB unit is not available thereby extending access to nearly all patients.

KEY POINTS

Efficacy of transplanting adequately dosed 1- or 2-cord blood units.

Umbilical cord blood transplantation: a maturing technology

The use of umbilical cord blood (CB) as a source of hematopoietic progenitor cells for patients with high-risk hematologic disorders receiving allogeneic hematopoietic cell transplantations (HCTs) has increased significantly. Single-institution and registry studies have shown a decreased relapse rate and an increased transplantation-related mortality rate with similar overall survival rates after allogeneic HCT with CB compared with other donor sources. The transplantation of double CB units has overcome the dose limitation inherent in a single CB unit and thus has markedly extended the use of CB to larger children and adults. Similarly, the use of reduced intensity conditioning in the CB transplantation setting has allowed the treatment of older patients who would be unable to tolerate the myeloablative regimens used in the original CB transplantation protocols.

Genetics of graft-versus-host disease: the major histocompatibility complex

Graft-versus-host disease (GVHD) is a potentially life-threatening complication of allogeneic hematopoietic cell transplantation. Many genes are presumed to be involved in GVHD, but the best characterized genetic system is that of the human major histocompatibility complex (MHC) located on chromosome 6. Among the hundreds of genes located within the MHC region, the best known and characterized are the classical HLA genes, HLA-A, C, B, DRB1, DQB1, and DPB1. They play a fundamental role in T cell immune responses, and HLA-A, C, and B also function as ligands for the natural killer cell immunoglobulin-like receptors involved in innate immunity. This review highlights the state-of-the art in the field of histocompatibility and immunogenetics of the MHC with respect to genetic risk factors for GVHD.

Allogeneic hematopoietic cell transplantation for MDS: for whom, when and how?

Hematopoietic cell transplantation (HCT) is currently the only treatment with curative potential for patients with myelodysplastic syndrome (MDS). However, treatment-related mortality and relapse have remained major barriers to uniform success. Therefore, important questions remain to be answered, such as whom to transplant, when and how. With reduced intensity conditioning (RIC) regimens, patients in their 70s and patients with comorbid conditions have been transplanted successfully, although the relapse incidence with this approach tends to be increased in comparison to high intensity regimens. Success rates are higher in patients transplanted at an early stage of their disease. Encouraging is the fact, that results with unrelated donors who are HLA-matched by high resolution typing are comparable to those achieved with HLA genotypically identical siblings. The establishment of cord blood as a source of stem cells, and the recent success with HLA-haploidentical related donors will allow the offering of HCT to virtually all patients. Dependent upon disease stage and characteristics, some 25% to 75% of transplanted patients will be cured. While 20%-30% of patients experience chronic medical problems after HCT, 70% report a "good to excellent" quality of life. New studies must focus on further reducing GVHD for all patients and on overcoming high relapse rates in patients with high risk disease.

Double umbilical cord blood transplantation: a study of early engraftment kinetics in leukocyte subsets using HLA-specific monoclonal antibodies

Single cord blood unit (CBU) predominance is usually established within the first month after double umbilical cord blood transplantation (UCBT). However, the kinetics of engraftment of the different leukocyte subsets and the mechanism of graft predominance is largely unknown. To investigate whether a differential engraftment might reveal a specific subset that could play a key role in the mechanism of graft predominance, we studied early engraftment kinetics of different leukocyte subpopulations by flow cytometry using human monoclonal antigen-specific human leukocyte antigen antibodies, directed against mismatched human leukocyte antigen-A or -B antigens between recipient and CBUs. Twenty-two patients, who had received a double UCBT preceded by a reduced-intensity conditioning regimen, were evaluated at days +11, +18, +25, and +32 posttransplantation. Single CBU predominance in the various leukocyte subsets was established within 18 days posttransplantation. CD4+ T cells of the dominant CBU showed early peripheral blood expansion. Moreover, chimerism in CD4+ and CD8+ T cell and natural killer cell subsets at day +11 was predictive of ultimate graft predominance. These findings show that engraftment kinetics of the various leukocyte subsets vary considerably after double UCBT and may suggest an important role for CD4+ T cells in a presumed alloreactive graft-versus-graft rejection.

Effect of HLA-matching recipients to donor noninherited maternal antigens on outcomes after mismatched umbilical cord blood transplantation for hematologic malignancy

Transplantation-related mortality (TRM) is high after HLA-mismatched umbilical cord blood (UCB) transplantation (UCBT). In utero, exposure to noninherited maternal antigen (NIMA) is recognized by the fetus, which induces T regulator cells to that haplotype. It is plausible that UCBTs in which recipients are matched to donor NIMAs may alleviate some of the excess mortality associated with this treatment. To explore this concept, we used marginal matched-pair Cox regression analysis to compare outcomes in 48 NIMA-matched UCBTs (ie, the NIMA of the donor UCB unit matched to the patient) and in 116 non-NIMA-matched UCBTs. All patients had a hematologic malignancy and received a single UCB unit. Cases and controls were matched on age, disease, disease status, transplantation-conditioning regimen, HLA match, and infused cell dose. TRM was lower after NIMA-matched UCBTs compared with NIMA-mismatched UCBTs (relative risk, 0.48; P = .05; 18% versus 32% at 5 years posttransplantation). Consequently, overall survival was higher after NIMA-matched UCBT. The 5-year probability of overall survival was 55% after NIMA-matched UCBTs versus 38% after NIMA-mismatched UCBTs (P = .04). When faced with the choice of multiple HLA-mismatched UCB units containing adequate cell doses, selecting an NIMA-matched UCB unit may improve survival after mismatched UCBT.

Beneficial effects of non-matched allogeneic cord blood mononuclear cells upon patients with idiopathic osteoporosis

Background

Immunological arguments and historical examples have shown that treatment with cord blood for non-hematopoietic activities, such as growth factor production and stimulation of angiogenesis, may not require matching or immune suppression.

Methods

To study the benefit of blood mononuclear cell therapy, 8 patients with idiopathic osteoporosis were given intermittent treatments with non-matched allogeneic cord blood mononuclear cells for 3 months. Morning fasting samples were collected for measuring urine N telopeptide of type-1 collagen, serum bone-specific alkaline phosphatase, and insulin-like growth factor 1 during one-year study.

Results

Clinical response was striking. Serum insulin-like growth factor 1 significantly increased in all patients at 3 months compared with baseline values, from 264.1 ± 107.0 to 384.4 ± 63.1 ng/mL (P = 0.002), with a tendency to return to baseline values at 12 months (312.9 ± 75.5 ng/mL, P = 0.083). In contrast, differences in serum bone-specific alkaline phosphatase and urine N telopeptide of type-1 collagen were not significant at 3 (P = 0.765, P = 0.057) or 12 months (P = 0.889, P = 0.122). A beneficial effect on bone density was observed in all patients at the lumbar spine. The mean bone mineral density calculated during therapy (0.6811 ± 0.1442 g/cm²) tended higher than baseline values (0.6239 ± 0.1362 g/cm², P < 0), and percentage change (median) varied from 8.85% at 3 months to 7.85% at one year. All patients are now well after one year.

Conclusions

The findings indicate that for these patients with idiopathic osteoporosis, treatment with cord blood mononuclear cells led to a significant increase in insulin-like growth factor 1 levels, which favors the increase in bone mineral density.

SIOG (International Society of Geriatric Oncology) Recommendations for Anthracycline Use in the Elderly

A taskforce of the International Society of Geriatric Oncology (SIOG) has recently submitted recommendations on the use of anthracyclines in elderly patients. Despite the aging of the population and the high proportion of elderly individuals in the population of patients with non-Hodgkin's lymphoma, the development of specialist expertise in the treatment of elderly patients with cancer is relatively recent. Treatment of the elderly is complex because they are a highly heterogeneous population, with large variations in health status, comorbidities and life expectancy. In addition, these patients are generally more susceptible than young patients to the cardiotoxic effects of anthracyclines. Strategies for assessing elderly patients with cancer, reducing the risk of congestive heart failure, and assessing the cardiotoxic effects of treatments are discussed. In addition, a summary of the SIOG recommendations is presented.

Cord blood transplantation in Western Australia

BACKGROUND/AIMS

Thirty-one umbilical cord blood transplants performed in Western Australia were retrospectively examined in order to document local experience and relevant prognostic factors. Three cord units were from human leucocyte antigen-matched siblings and the remainder were unrelated single (n= 22) or double (n= 6) cord blood transplants.

METHODS

Twenty patients were transplanted for malignant conditions and 11 for non-malignant conditions. Cord units contained a median of 5.6 × 107 total nucleated cells/kg and 1.4 × 105 CD34+ cells/kg. Cumulative incidence of neutrophil engraftment was 76% at day 60.

RESULTS

Of those who did not engraft, two patients remain alive following subsequent allogeneic bone marrow transplant. There were no deaths caused by graft-versus-host disease. Overall survival at median follow up of 28 months was 62%. Two year overall survival was influenced by type of disease (non-malignant = 91 ± 9% vs malignant = 41 ± 13%, P= 0.005), total nucleated cell dose (>3.5 × 107/kg = 87 ± 9% vs <3.5 × 107/kg = 34 ± 15%, P= 0.01) and CD34 dose (>1.7 × 105/kg = 92% vs <1.7 × 105/kg = 46%, P= 0.04). Age and human leucocyte antigen match did not influence survival. Four relapses occurred, all of which were fatal.

CONCLUSION

Cord blood transplantation for malignant and non-malignant disease is practised in Western Australia and outcomes are satisfactory. Trends and techniques in cord blood transplantation in this state are comparable with those observed nationally and overseas. Although numbers are small, cell dose appears to be predictive of overall survival

Cord blood stem cells for hematopoietic transplantation

Cord blood (CB) is an important alternative source of hematopoietic stem cells (HSCs) for transplantation today. The principal drawbacks of cord blood transplantation are the limited number of hematopoietic stem cells and a long time to engraftment. Several promising approaches for engraftment enhancement are under intensive investigation. Such are transplantation with two cord blood units, co transplantation of cord blood and haploidentical HSCs and different methods for expansion of cord blood hematopoietic stem cells. In addition there are several ways for improving of homing of HSCs such as co- infusion of CB hematopoietic stem cells and mesenchymal stem cells, administration of parathyroid hormone (PTH), intra- bone transplantation and targeting the CXCR4/SDF1 system. These strategies are expected to increase the availability of transplantation to adults, for whom the chance to find a cord blood suitable for a single unit transplant is small. Recent advances in elucidation of the molecular mechanisms responsible for the proliferation and self-renewal of hematopoietic stem cells may bring further improvement of the outcomes of cord blood transplantation. This review summarizes the recent progress in the field of cord blood derived hematopoietic stem cells. It presents the strategies applied and points out directions for the future.

Activated T cells from umbilical cord blood armed with anti-CD3 × anti-CD20 bispecific antibody mediate specific cytotoxicity against CD20+ targets with minimal allogeneic reactivity: a strategy for providing antitumor effects after cord blood transplants

BACKGROUND

In this study, we asked whether anti-CD3-activated T cells (ATCs) from cord blood (CB) could be expanded and targeted to solid tumors or hematologic malignancies for infusions after unrelated CB stem cell transplant and whether cord blood ATCs (CBATCs) could reduce alloresponsiveness.

STUDY DESIGN AND METHODS

CB mononuclear cells (MNCs) were activated with anti-CD3 (20 ng/mL) and expanded for 14 days in interleukin-2 (100 IU/mL). CBATCs were armed with anti-CD3 × anti-CD20 (CD20Bi) or anti-CD3 × anti-Her2 (Her2Bi) bispecific antibodies (CBaATCs) and tested for specific cytotoxicity, cytokine secretion, and alloresponsiveness.

RESULTS

Our results show the mean expansion of CBATCs to be 37-fold after 14 days of culture from either frozen (n=4) or fresh (n=4) CB units. Cytotoxicity was optimal when CBATCs were armed with 50 ng of CD20Bi/10(6) cells. Cytotoxicity peaked between Day 8 and Day 10 for both bispecific antibodies. At an effector-to-target ratio of 25:1, the mean cytotoxicities of CBATCs armed with Her2Bi or CD20Bi were 40% (n=4) and 30% (n=4), respectively. CBaATCs exhibited peak specific interferon-γ enzyme-linked immunosorbent spots on Day 10. CBATCs and CBaATCs suppressed responsiveness to alloantigens by 20% to 50% when compared with normal allogeneic peripheral blood MNC response.

CONCLUSION

We showed that armed CBATCs mediate specific cytotoxicity, secrete low levels of cytokines and chemokines, and demonstrate attenuated response to alloantigens.

Double cord blood transplantation: co-operation or competition?

Over the last two decades umbilical cord blood (UCB) transplantation (UCBT) is increasingly used for a variety of malignant and benign hematological and other diseases. The main factor that limits the use of UCB to low weight recipients, mainly children and adolescents, is its low progenitor cell content. Various alternatives have been exploited to overcome this difficulty, including the transplantation of two UCB units (double umbilical cord blood transplantation, dUCBT). Following dUCBT, donor(s) hematopoietic stem cells (HSC) can be detected in the peripheral blood of the recipient as soon as 14 days post-transplantation. Sustained engraftment of HSC from one or both donors can be observed- dominance or mixed chimerism respectively, although single donor unit dominance has been observed in over 85% of patients. The underlying biology, which accounts for the interactions both between the two infused UCB units- cooperative or competitive, and with the recipient's immune system, has not been elucidated.

Towards responsible cord blood banking models

On 31 May 2010, 14 072 567 bone marrow/apheresis donors registered in 44 countries and 426 501 cord blood units banked in 26 countries for public use were available to treat candidates to haemopoietic stem cell transplant lacking a family related compatible donor. Despite these impressive numbers, additional efforts are required to ensure that all patients, including those from ethnic minorities, can promptly find a suitable donor. Governments, clinicians, scientists, patients and stakeholders should share the responsibility to develop haemopoietic stem cell donation and cord blood banking models able to fully match all patient needs. In this regard, current scientific evidence and prevalent opinions among expert clinicians support solidaristic cord blood donation for public use against the alternative option of commercial autologous cord blood storage.

An overview of the progress on double umbilical cord blood transplantation

Umbilical cord blood transplantation has been increasingly used over the past years for both malignant and non-malignant hematologic and other diseases as an alternative to mismatched-related or matched-unrelated bone marrow or peripheral blood hematopoietic stem cell transplantation. A disadvantage of cord blood is its low cell content which limits cord blood transplantation to generally low weight recipients, such as children. Various alternatives have been used to overcome this limitation, including co-infusion of two partially HLA-matched cord blood units. According to Eurocord Registry data, this strategy has been applied in approximately 993 adult patients with hematologic diseases since the first double umbilical cord blood transplantation in 1999. In fact, since 2005, the number of adult patients receiving double umbilical cord blood transplantation has surpassed the number of adults transplanted with single cord blood units. The engraftment rate is comparable for both single and double umbilical cord blood transplantation, although the latter is accompanied by a higher incidence of grade II acute graft-versus-host disease and lower leukemia relapse for patients in first complete remission. In the majority of patients undergoing double umbilical cord blood transplantation, transient chimerism, due to the presence of cells from both donor units early post transplant, is replaced by sustained dominance of one unit from which long-term hematopoiesis is derived. Although the biology and the factors that determine unit dominance have not been clarified, the implication of immune-mediated mechanisms has been reported. Preliminary data have demonstrated the safety of double umbilical cord blood transplantation. Ongoing clinical trials and prolonged follow up of the patients will clarify the immunology and determine the efficacy of this approach. We present here a brief overview of the clinical experience on double umbilical cord blood transplantation and its underlying biology.

Influence of infused cell dose and HLA match on engraftment after double-unit cord blood allografts

The influence of cell dose and human leukocyte antigen (HLA) match on double-unit cord blood (CB) engraftment is not established. Therefore, we analyzed the impact of cell dose and high-resolution HLA match on neutrophil engraftment in 84 double-unit CB transplant recipients. The 94% sustained engraftment rate was accounted for by 1 unit in nearly all patients. Higher CD3(+) cell doses (P = .04) and percentage of CD34(+) cell viability (P = .008) were associated with unit dominance. After myeloablative conditioning, higher dominant unit total nucleated cell (TNC), CD34(+) cell, and colony-forming unit doses were associated with higher sustained engraftment and faster neutrophil recovery (P = .07, P = .0008, and P < .0001, respectively). Total infused TNC (P = .0007) and CD3(+) cell doses (P = .001) also significantly influenced engraftment. At high-resolution extensive donor-recipient HLA disparity was frequent, but had no influence on engraftment (P = .66), or unit dominance (P = .13). Although the unit-unit HLA match also did not affect sustained engraftment (P = 1.0), recipients of units closely (7-10 to 10-10) HLA-matched to each other were more likely to demonstrate initial engraftment of both units (P < .0001). Our findings have important implications for unit selection and provide further insight into double-unit biology.

A preclinical model of double- versus single-unit unrelated cord blood transplantation

Cord blood transplantation (CBT) with units containing total nucleated cell (TNC) dose >2.5 x 10(7)/kg is associated with improved engraftment and decreased transplant-related mortality. For many adults no single cord blood units are available that meet the cell dose requirements. We developed a dog model of CBT to evaluate approaches to overcome the problem of low cell dose cord blood units. This study primarily compared double- versus single-unit CBT. Unrelated dogs were bred and cord blood units were harvested. We identified unrelated recipients that were dog leukocyte antigen (DLA)-88 (class I) and DLA-DRB1 (class II) allele-matched with cryopreserved units. Each unit contained Collapse

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MESH Headings

• Animals
• Cord Blood Stem Cell Transplantation/adverse effects
• Cord Blood Stem Cell Transplantation/methods
• Disease Models, Animal
• Dogs
• Female
• Graft Rejection/immunology
• Male
• Survival Rate

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Grants

• U19 AI067770-02 NIAID NIH HHS
• U19 AI067770-030005 NIAID NIH HHS
• U19 AI067770-05 NIAID NIH HHS
• U19 AI 067770 NIAID NIH HHS
• U19 AI067770-01 NIAID NIH HHS
• R01 DK042716 NIDDK NIH HHS
• DK42716 NIDDK NIH HHS
• R01 DK042716-15 NIDDK NIH HHS
• P30 CA015704 NCI NIH HHS
• CA78902 NCI NIH HHS
• U19 AI067770 NIAID NIH HHS
• U19 AI067770-050005 NIAID NIH HHS
• P30 CA015704-35 NCI NIH HHS
• CA15704 NCI NIH HHS
• U19 AI067770-010005 NIAID NIH HHS
• R01 DK042716-16 NIDDK NIH HHS
• P30 CA015704-34 NCI NIH HHS
• U19 AI067770-04 NIAID NIH HHS
• P01 CA078902 NCI NIH HHS
• P01 CA078902-11 NCI NIH HHS
• P01 CA078902-10 NCI NIH HHS
• U19 AI067770-040005 NIAID NIH HHS
• U19 AI067770-020005 NIAID NIH HHS

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Affiliation(s)

George E Georges Clinical Research Division, Fred Hutchinson Cancer Research Center, University of Washington, Seattle, Washington 98109, USA.
Vladimir Lesnikov
Szczepan W Baran
Anna Aragon
Marina Lesnikova
Robert Jordan
Ya-Ju Laura Yang
Murad Y Yunusov
Eustacia Zellmer
Shelly Heimfeld
Gopalakrishnan M Venkataraman
Michael A Harkey
Scott S Graves
Rainer Storb
Barry E Storer
Richard A Nash

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Hematopoietic stem cell transplantation for MDS

Hematopoietic stem cell transplantation (HSCT) offers potentially curative therapy for patients with myelodysplastic syndromes (MDS). However, as the majority of patients with MDS are in the seventh or eighth decade of life, conventional transplant regimens have been used only infrequently, and only with the development of reduced-intensity conditioning has transplantation been applied more broadly to older patients. Dependent upon disease status at the time of transplantation, 30% to 70% of patients can be expected to be cured of their disease and survive long term. However, posttransplant relapse and graft-versus-host disease (GVHD) remain problems and further investigations are needed.