Alternative Allogeneic Donor Sources for Transplantation for Childhood Diseases: Unrelated Cord Blood and Haploidentical Family Donors

Haploidentical vs. HLA-matched donor hematopoietic stem-cell transplantation for pediatric patients with acute lymphoblastic leukemia in second remission: A collaborative retrospective study of the Spanish Group for Bone Marrow Transplantation in Children (GETMON/GETH) and the Spanish Childhood Relapsed ALL Board (ReALLNet)

Introduction

Studies addressing the role of haploidentical as alternative to HLA-matched donors for stem cell transplantation (SCT) often include patients with diverse hematological malignancies in different remission statuses.

Methods

We compared outcomes of children with acute lymphoblastic leukemia (ALL) undergoing SCT in second complete remission (CR2) from haploidentical (n = 25) versus HLA-matched donor (n = 51).

Results

Patients were equally distributed across both groups according to age, immunophenotype, time to and site of relapse, relapse risk-group allocation, and minimal residual disease (MRD) before SCT. Incidence of graft failure, acute graft versus host disease (GVHD), and other early complications did not differ between both groups. We found no differences in overall survival (58.7% versus 59.5%; p = .8), leukemia free survival (LFS) (48% versus 36.4%; p = .5), event free survival (40% versus 34.4%; p = .69), cumulative incidence (CI) of subsequent relapse (28% versus 40.9%; p = .69), treatment related mortality (24% versus 23.6%; p = .83), CI of cGVHD (4.5% versus 18.7%; p = .2), and chronic GVHD-free and leukemia-free survival (44% versus 26.3%; p = .3) after haploidentical donor SCT. Chronic GVHD (HR = 0.09; p=.02) had protective impact, and MRD ≥ 0.01% before SCT (HR = 2.59; p=.01) had unfavorable impact on LFS.

Discussion

These results support the role of haploidentical donor SCT in children with ALL in CR2.

T-Cell Depleted Haploidentical Transplantation in Children With Hematological Malignancies: A Comparison Between CD3+/CD19+ and TCRαβ+/CD19+ Depletion Platforms

Background

T-cell depleted (TCD) haploidentical transplantation using CD3+/CD19+ and TCRαβ+/CD19+ depletion techniques has been increasingly used in children with hematological malignancies. We present a retrospective study aimed to compare transplant outcomes in children with leukemia receiving a TCD haploidentical transplant using either CD3+/CD19+ or TCRαβ+/CD19+ platforms.

Methods

A total of 159 children with leukemia (ALL=80) (AML=79) that received a TCD haploidentical transplantation using either CD3+/CD19+ (n=79) or TCRαβ+/CD19+ (n=80) platforms between 2005 and 2020 were included. Median age was 9 years in both groups. There were no differences in patient, donor, and transplant characteristics between groups except for donor KIR B genotype more frequent in the TCRαβ+/CD19+ group (91%) than in the CD3+/CD19+ group (76%) (p=0.009) and a high number of NK+ cells and lower CD19+ cells infused in the TCRαβ+/CD19+ group (35.32x106/kg and 0.06 x106/Kg) than in the CD3+/CD19 group (24.6x106/Kg and 0.25 x106/Kg) (p=0.04 and p=0.0001), respectively. Conditioning was based on TBF. Median follow-up for survivors was 11 years (range; 8-16 y) in CD3+/CD19+ group and 5 years (range; 2-9 y) in the TCRαβ+/CD19+ group.

Results

Engraftment kinetics were similar in both groups (13 days for neutrophils and 10 days for platelets). There was no difference in the incidence of acute GvHD II-IV (29 ± 5% in the CD3+/CD19+ group vs 38 ± 5% in the TCRαβ+/CD19+ group) and chronic GvHD (32 ± 5% vs 23 ± 4%, respectively). NRM was 23 ± 5% in the CD3+/CD19+group vs 21 ± 4% in the TCRαβ+/CD19+group. Relapse incidence was also similar, 32 ± 5% vs 34 ± 6%, respectively. DFS and OS were not different (45 ± 5% vs 45 ± 6% and 53 ± 6% vs 58 ± 6% respectively). As there were no differences on transplant outcomes between groups, we further analyzed all patients together for risk factors associated with transplant outcomes. On multivariate analysis, we identified that early disease status at transplant (HR: 0.16; 95%CI (0.07-0.35) (p=0.0001), presence of cGvHD (HR: 0.38; 95%CI (0.20-0.70) (p= 0.002), and donor KIR-B genotype (HR: 0.50; 95%CI (0.32-0.90) (p=0.04) were associated with better DFS.

Conclusions

Our data suggest that there are no advantages in transplant outcomes between TCD platforms. Risk factors for survival are dependent on disease characteristic, donor KIR genotype, and chronic GvHD rather than the TCD platform used.

Comparison of clinical outcomes between unrelated single umbilical cord blood and "ex-vivo" T-cell depleted haploidentical transplantation in children with hematological malignancies

BACKGROUND

Over the last two decades, umbilical cord blood (UCB) and haploidentical transplantation (HaploHSCT) have emerged as alternative sources of hematopoietic stem cell for allogeneic transplantation. There are few retrospective studies and no prospective studies comparing both types of alternative transplantation in pediatric patients.

RESULTS

We analyzed the data of 134 children with hematological malignancies who received a hematopoietic stem cell transplantation from a single umbilical cord blood (UCB) (n = 42) or an "ex-vivo" T-cell depleted transplant from a haploidentical-related donor (HaploHSCT) (n = 92) between 1996 and 2014. Hematological recovery was faster after HaploHSCT than the UCB transplant group (median times to neutrophil and platelet recovery: 13 vs. 16 days, 10 vs. 57 days, respectively) (P < 0.001). The HaploHSCT group had a significantly early immune reconstitution based on NK and CD8 + T cells compared with the UCB group. However, after the first year post-transplantation, HaploHSCT had a lower number of CD4 + T and B lymphocytes compared with the UCB transplant recipients. The cumulative incidence of TRM was 29±8% in the HaploHSCT group versus 40±5% in the UCB group. Relapse incidence was 21±7% in the HaploHSCT group and 19±8% in the UCB group. Probability of DFS was 58±8% in the HaploHSCT group versus 40±9% in the UCB group (P = 0.051).

CONCLUSIONS

TCD haploidentical transplant is associated with advantages in terms of engraftment and early immune reconstitution kinetics. TCD haploidentical transplant was associated with lower incidence of infectious and non-infectious complications, especially in the early phases of the transplant compared with UCB transplant recipients. However, there are no advantages in transplant outcomes compared with UCB transplant.

Cellular Therapy in Pediatric Hematologic Malignancies

Advances in cellular therapies for pediatric patients have created many opportunities for improved survival with reduced morbidity. This article reviews current cellular therapies in pediatric hematological malignancy, including the most updated practices in hematopoietic stem cell transplant and the use of chimeric antigen receptor (CAR) therapy in T cells. Hematopoietic stem cell transplant has evolved with improvements in chemotherapy regimens, immunosuppression, and donor-matching options. Novel therapies in development which will likely further improve the options for patients are reviewed including Natural Killer, Regulatory T-cells and αβ depletion.

Haploidentical stem cell transplant with post-transplantation cyclophosphamide and mini-dose methotrexate in children

BACKGROUND

Haploidentical stem cell transplantation (haplo-SCT) is an option for patients without human leukocyte antigen-matched related or unrelated donor. Post-transplantation cyclophosphamide (PTCy) is an effective method of graft versus host disease (GVHD) prophylaxis and permits the use of T-cell replete grafts in settings were ex vivo manipulation is not feasible.

METHODS

A retrospective study among patients younger than 18 years, with a history of hematologic malignancies who underwent haplo-SCT between 2012 and 2016. All patients received a preparative regimen of fludarabine, busulfan, and 400 cGy total body irradiation or melphalan. Post-transplant GvHD prophylaxis consisted either of PTCy (50 mg/kg on Days + 3 and + 4) and cyclosporine (CSA) plus mycophenolate (MMF) (15 mg/kg/dose, thrice daily, per os), or mini-dose methotrexate (MTX; 5 mg/m² dose) on Days + 5, +7, +10, and + 15.

RESULTS

A total of 52 children were included, whose median age was 9 years (interquartile range, 4.9-14; range, 1.2-17 years), and 63% were males. The most common complications were cytomegalovirus reactivation (57%) and hemorrhagic cystitis (36%). The acute GVHD prophylaxis was PTCy, CSA, and mini-dose MTX in 42 (81%) patients, and 10 (19%) patients received PTCy, CSA, and MMF. The cumulative incidence of acute GvHD II-IV, acute GvHD III-IV, and chronic GvHD were 42%, 8.5%, and 19%, respectively. Grades I-IV acute GvHD occurred in 100% of the patients who received prophylaxis with CSA and MMF, and 62% who received CSA and mini-dose MTX (p = .055). The transplant-related mortality at 100 days was 18%. The 5-year overall and event-free survival were 59% and 57%, respectively.

CONCLUSIONS

Haplo-SCT with PT/Cy can be an available, safe, and feasible option for children with hematologic malignancies; meanwhile, the use of mini-dose of MTX was associated with lower rates of acute GVHD. However, our results require further support from prospective randomized studies to improve the efficacy of this prophylactic strategy.

Immunophenotypic, cytotoxic, proteomic and genomic characterization of human cord blood vs. peripheral blood CD56Dim NK cells

Unrelated cord blood (CB) is an excellent alternative as an allogeneic donor source for stem cell transplantation. CB transplantation is associated with lower incidence of severe acute graft versus host disease (GVHD) and chronic GVHD but similar rates of malignant relapse compared with other unrelated donor cell transplants. NK cells are critical innate immune components and the comparison of CB vs. peripheral blood (PB) NK cells is relatively unknown. NK cell receptor expression, cell function, and maturation may play a role in the risk of relapse after CB transplant. We investigated CB vs. PB NK cell subset cytotoxicity, function, receptor expression, and genomic and proteomic signatures. The CB CD56^dim compared with PB CD56^dim demonstrated significantly increased expression of NKG2A and NKG2D, respectively. CB vs. PB CD56^dim NK cells had significantly decreased in vitro cytotoxicity against a variety of non-Hodgkin lymphoma targets. Various proteins were significantly under- and over-expressed in CB vs. PB CD56^dim NK cells. Microarray analyses and qRT-PCR in CB vs. PB CD56^dim demonstrated significantly increased expression of genes in cell regulation and development of apoptosis, respectively. In summary, CB vs. PB CD56^dim NK cells appear to be earlier in development, have decreased functional activity, and increased capacity for programmed cell death, suggesting that CB NK cells require functional and maturational stimulation to achieve similar functional levels as PB CD56^dim NK cells.

Stem cell transplantation in sickle cell disease: therapeutic potential and challenges faced

INTRODUCTION

Sickle cell disease (SCD) is the most common inherited hemoglobinopathy worldwide, and is a life-limiting disease with limited therapeutic options to reduce disease severity. Despite being a monogenic disorder, the clinical phenotypes of SCD are variable, with few reliable predictors of disease severity easily identifying patients where the benefits of curative therapy outweigh the risks. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative option, though significant advances in gene therapy raise the promise for additional curative methods. Areas covered: Allogeneic transplantation in SCD has evolved and improved over the last two decades, now offering a standard of care curative option using a human leukocyte antigen (HLA)-matched sibling donor. Many of the seminal transplantation studies are reviewed here, demonstrating how initial failures and successes have influenced and led to current HSCT strategies. Such strategies aim to overcome setbacks and limitations, and focus on conditioning regimens, immune suppression methods, the use alternative donor sources, and gene therapy approaches. Expert commentary: SCD is a curable disease. Each dedicated effort to refine transplantation methods, expand the donor pool, and bring gene therapy models to fruition will make enormous impacts reducing disease burden and improving outcomes and quality of life for patients with SCD.

Cord Blood Banking for Potential Future Transplantation

This policy statement is intended to provide information to guide pediatricians, obstetricians, and other medical specialists and health care providers in responding to parents' questions about cord blood donation and banking as well as the types (public versus private) and quality of cord blood banks. Cord blood is an excellent source of stem cells for hematopoietic stem cell transplantation in children with some fatal diseases. Cord blood transplantation offers another method of definitive therapy for infants, children, and adults with certain hematologic malignancies, hemoglobinopathies, severe forms of T-lymphocyte and other immunodeficiencies, and metabolic diseases. The development of universal screening for severe immunodeficiency assay in a growing number of states is likely to increase the number of cord blood transplants. Both public and private cord blood banks worldwide hold hundreds of thousands of cord blood units designated for the treatment of fatal or debilitating illnesses. The procurement, characterization, and cryopreservation of cord blood is free for families who choose public banking. However, the family cost for private banking is significant and not covered by insurance, and the unit may never be used. Quality-assessment reviews by several national and international accrediting bodies show private cord blood banks to be underused for treatment, less regulated for quality control, and more expensive for the family than public cord blood banks. There is an unquestionable need to study the use of cord blood banking to make new and important alternative means of reconstituting the hematopoietic blood system in patients with malignancies and blood disorders and possibly regenerating tissue systems in the future. Recommendations regarding appropriate ethical and operational standards (including informed consent policies, financial disclosures, and conflict-of-interest policies) are provided for physicians, institutions, and organizations that operate or have a relationship with cord blood banking programs. The information on all aspects of cord blood banking gathered in this policy statement will facilitate parental choice for public or private cord blood banking.

Reduced Toxicity Conditioning and Allogeneic Hematopoietic Progenitor Cell Transplantation for Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa is a severe, incurable, inherited blistering disease caused by COL7A1 mutations. Emerging evidence suggests hematopoietic progenitor cells (HPCs) can be reprogrammed into skin; HPC-derived cells can restore COL7 expression in COL7-deficient mice. We report two children with recessive dystrophic epidermolysis bullosa treated with reduced-toxicity conditioning and HLA-matched HPC transplantation.

Alternative donor transplant of benign primary hematologic disorders

Hematopoietic SCT is currently the only curative therapy for a range of benign inherited and acquired primary hematologic disorders in children, including BM failure syndromes and hemoglobinopathies. The preferred HLA-matched sibling donor is available for only about 25% of such children. However, there has been substantial progress over the last four decades in the use of alternative donors for those without a matched sibling-including HLA-matched unrelated donors, HLA-haploidentical related donors and unrelated-donor umbilical cord blood-so that it is now possible to find a donor for almost every child requiring an allograft. Below, we summarize the relative merits and limitations of the different alternative donors for benign hematologic conditions, first generally, and then in relation to specific disorders, and suggest recommendations for selecting such an alternative donor.

Efficiency of allogeneic hematopoietic SCT from HLA fully-matched non-sibling relatives: a new prospect of exploiting extended family search

The best donors for hematopoietic SCT (HSCT) are fully-matched siblings. In patients without fully-matched siblings, HLA registries or cord blood banks are alternative strategies with some restrictions. Owing to the high rate of consanguineous marriage in our country, between 2006 and 2013, extended family searches were undertaken in Hematology-Oncology Research Center and Stem Cell Transplantation (HORCSCT), Tehran, Iran, in 523 HSCT candidates with parental consanguinity and no available HLA identical sibling. Fully-matched other-relative donors were found for 109 cases. We retrospectively studied the HSCT outcome in these patients. Median time to neutrophil engraftment was 13 days (range: 9-31days). In 83 patients, full chimerism and in 17 patients, mixed chimerism was achieved. Acute GvHD (aGvHD) grade II-IV appeared in 36 patients (33%). The frequency of aGvHD development in various familial subgroups was NS. Five patients expired before day+100. In the surviving 104 cases, chronic GvHD developed in 20 patients (19.2%). The distantly related subgroup had significantly a higher rate of cGvHD (P=0.04). The 2-year OS and disease-free survival (DFS) were 76.7±4.5% and 71.7±4.7%, respectively. No significant difference in OS (P=0.30) and DFS (P=0.80) was unraveled between various familial relationships. Our considerable rate of fully-matched non-sibling family members and the favorable outcome support the rationale for extended family search in regions where consanguineous marriage is widely practiced.

Smoothing the crescent curve: sickle cell disease

Sickle cell disease (SCD) is an inherited disorder secondary to a point mutation at the sixth position of the beta chain of human hemoglobin that results in the replacement of valine for glutamic acid. This recessive genetic abnormality precipitates the polymerization of the deoxygenated form of hemoglobin S that induces a major distortion of red blood cells (sickle red blood cells), which decreases sickle red blood cell deformability, leading to chronic hemolysis and vasoocclusion. These processes can result in severe complications, including chronic pain, end organ dysfunction, stroke, and early mortality. The only proven curative therapy for patients with SCD is myeloablative conditioning and allogeneic stem cell transplantation from HLA-matched sibling donors. In this review, we discuss the most recent advances in allogeneic stem cell transplantation in SCD, including more novel approaches such as reduced toxicity conditioning and the use of alternative allogeneic donors (matched unrelated donors, umbilical cord blood transplantation, haploidentical donors) and autologous gene correction stem cell strategies. Prospects are bright for new stem cell approaches for patients with SCD that will enable curative stem and genetic correction therapies for a greater number of patients suffering from this chronic and debilitating condition.

Hematopoietic stem cell transplantation for sickle cell disease: state of the science

Sickle cell disease (SCD) is an inherited disorder secondary to a point mutation at the sixth position of the beta chain of human hemoglobin resulting in the replacement of valine for glutamic acid. This recessive genetic abnormality precipitates the polymerization of the deoxygenated form of hemoglobin S inducing a major distortion of red blood cells (S-RBC), which decreases S-RBC deformability leading to chronic hemolysis and vaso-occlusion. These processes can result in severe complications including chronic pain, end-organ dysfunction, stroke, and early mortality. The only proven curative therapy for patients with SCD is myeloablative conditioning and allogeneic stem cell transplantation from HLA-matched sibling donors. In this review, we discuss the most recent advances in allogeneic stem cell transplantation in patients with SCD including more novel approaches such as reduced toxicity conditioning and the use of alternative allogeneic donors, including matched unrelated donors (MUDs), unrelated cord blood donors (UCBT), and familial haploidentical (FHI) donors. The results to date are very encouraging regarding allogeneic stem cell transplantation for patients with SCD including high survival rates and enabling a greater number of patients suffering from this chronic and debilitating condition to receive curative allogeneic stem cell therapies. However, we still have several areas to investigate and barriers to overcome to successfully cure the majority of patients with severe SCD through allogeneic stem cell therapies.

Fostering public cord blood banking and research in Canada

In June 2013, Canadian Blood Services (CBS) established the National Public Cord Blood Bank (NPCBB) accessible to Canadian and international patients and researchers. The NPCBB promotes efforts that contribute to research and improved clinical care by making units not suitable for banking or transplantation available for research. In the context of the NPCBB of the CBS, this article will focus on the practical tools (e.g., consent protocols) developed to optimize umbilical cord blood (UCB) banking and research while enabling ethical provenance of UCB stem cells. The Canadian approach represents an ideal model for comparison as it is a country in which the national public bank (and other regional/provincial public banks) coexists with private companies.

Pilot trial of risk-adapted cyclophosphamide intensity based conditioning and HLA matched sibling and unrelated cord blood stem cell transplantation in newly diagnosed pediatric and adolescent recipients with acquired severe aplastic anemia

BACKGROUND

Cyclophosphamide-based conditioning regimens and allogeneic hematopoietic stem cell transplantation (AlloHSCT) from matched related donors (MRD) has resulted in the highest survival rates in children and adolescents with acquired severe aplastic anemia (SAA). Time to transplant has consistently been associated with decreased overall survival. Reduced toxicity conditioning and AlloHSCT has been used successfully in other pediatric non-malignant diseases.

PROCEDURE

We piloted a risk-adapted AlloHSCT approach, using fludarabine and anti-thymocyte globulin based conditioning with high (200 mg/kg) and low (60 mg/kg) dose cyclophosphamide as upfront treatment in newly diagnosed pediatric patients with acquired SAA incorporating alternative donor sources, including cord blood. Average risk for non-engraftment patients with <10 transfusions received low dose cyclophosphamide (60 mg/kg); High Risk, those with ≥10 transfusions received conditioning regimen with higher intensity cyclophosphamide (200 mg/kg).

RESULTS

Seventeen patients were enrolled and underwent AlloHSCT including 12 males and 5 females with mean age of 8 years (range 3-16), and median follow-up time of 39 months (range 1-135). Donor sources included MRD BM (6/6 [n = 9], 5/6 [n = 2]) and unrelated CB (5/6 [n = 4], 4/6 [n = 2]). Five year OS was 67.6% (37.9-85.4). Three secondary graft failures (17.6%) occurred in the low dose cyclophosphamide arm.

CONCLUSIONS

Upfront treatment with risk-adapted cyclophosphamide conditioning AlloSCT is well tolerated for the management of newly diagnosed pediatric and adolescent patients with acquired SAA. However, the increased risk of graft rejection in the lower dose arm warrants additional research regarding the optimal intensity of cyclophosphamide-based conditioning regimen to reduce toxicity without increasing graft failure.

New frontiers in pediatric Allo-SCT

The inaugural meeting of 'New Frontiers in Pediatric Allogeneic Stem Cell Transplantation' organized by the Pediatric Blood and Transplant Consortium (PBMTC) was held at the American Society of Pediatric Hematology and Oncology Annual Meeting. This meeting provided an international platform for physicians and investigators active in the research and utilization of pediatric Allo-SCT in children and adolescents with malignant and non-malignant disease (NMD), to share information and develop future collaborative strategies. The primary objectives of the conference included: (1) to present advances in Allo-SCT in pediatric ALL and novel pre and post-transplant immunotherapy; (2) to highlight new strategies in alternative allogeneic stem cell donor sources for children and adolescents with non-malignant hematological disorders; (3) to discuss timing of immune reconstitution after Allo-SCT and methods of facilitating more rapid recovery of immunity; (4) to identify strategies of utilizing Allo-SCT in pediatric myeloproliferative disorders; (5) to develop diagnostic and therapeutic approaches to hematological complications post pediatric Allo-SCT; (6) to enhance the understanding of new novel cellular therapeutic approaches to pediatric malignant and non-malignant hematological disorders; and (7) to discuss optimizing drug therapy in pediatric recipients of Allo-SCT. This paper will provide a brief overview of the conference.

Unrelated donor cord blood transplantation for non-malignant disorders in children and adolescents

This study analyzes the data reported to the Korean Cord Blood Registry between 1994 and 2008, involving children and adolescents with non-malignant diseases. Sixty-five patients were evaluated in this study: SAA (n = 24), iBMFS, (n = 16), and primary immune deficiency/inherited metabolic disorder (n = 25). The CI of neutrophil recovery was 73.3% on day 42. By day 100, the CI of acute grade II-IV graft-versus-host disease was 32.3%. At a median follow-up of 71 months, five-yr OS was 50.7%. The survival rate (37.5%) and CI of neutrophil engraftment (37.5%) were lowest in patients with iBMFS. Deaths were mainly due to infection, pulmonary complications, and hemorrhage. In a multivariate analysis, the presence of >3.91 × 10(5) /kg of infused CD34 + cells was the only factor consistently identified as significantly associated with neutrophil engraftment (p = 0.04) and OS (p = 0.03). UCBT using optimal cell doses appears to be a feasible therapy for non-malignant diseases in children and adolescents for whom there is no appropriate HLA-matched related donor. Strategies to reduce transplant-related toxicities would improve the outcomes of UCBT in non-malignant diseases.

[Hematopoietic stem cell transplantation in 2012: who? Where? How?]

Allogeneic bone marrow transplantation has dramatically changed over the years since its beginnings. The diseases treated with transplantation (malignant hemopathies, severe benign hemopathies such as congenital or acquired congenital medullary aplasia, hemoglobinopathies, as well as severe immune system deficiencies and certain overload diseases), stem cell sources (bone marrow, peripheral stem cells, placental blood), donor types (intrafamilial, nonrelated, totally or partially compatible), conditioning regimen (immunosuppressors, graft manipulation), and supportive care increasingly vary. Allogeneic stem cell transplantation and more widely cellular therapies now need to be discussed. In this paper, we propose an overview of these therapies in 2012 for pediatric patients.

Allogeneic cellular and autologous stem cell therapy for sickle cell disease: 'whom, when and how'

Sickle cell disease (SCD) is an autosomal recessive inherited hematological disorder characterized by chronic hemolysis and vaso-occlusion, resulting in multiorgan dysfunction and premature death. The only known curative therapy for patients with severe SCD is myeloablative conditioning and allo-SCT from HLA-matched sibling donors. In this state of the art review, we discuss current and future considerations including patient selection/eligibility, intensity of conditioning regimens, allogeneic graft sources, graft manipulation, mixed donor chimerism, organ function and stability and autologous gene correction stem cell strategies. Recent novel approaches to promote mixed donor chimerism have included the use of matched unrelated adult donors, umbilical cord blood donors, haploidentical familial donors and the utilization of nonmyeloablative, such as reduced intensity and reduced toxicity conditioning regimens. Future strategies will include gene therapy and autologous gene correction stem cell designs. Prospects are bright for novel stem and cellular approaches for patients with severe SCD, and we are currently at the end of the beginning for utilizing cellular therapeutics for the curative treatment of this chronic and debilitating condition.

Analysis of 120 pediatric patients with nonmalignant disorders transplanted using unrelated plasma-depleted or -reduced cord blood

BACKGROUND

Unrelated cord blood (CB) is an important stem cell source for unrelated hematopoietic cell transplantation (HCT) of patients with nonmalignant disorders. Processing methods to prepare red blood cell-reduced CB units incur significant nucleated cell loss. In contrast, plasma depletion or reduction (PDR) processing of CB units entails the removal of only a portion of the plasma with minimal nucleated cell loss. However, there are relatively limited data regarding outcomes of CB transplants using units processed by PDR.

STUDY DESIGN AND METHODS

A Center for International Blood and Marrow Transplant Research (CIBMTR)-audited analysis was performed on 120 pediatric patients with nonmalignant disorders transplanted between November 2001 and January 2008 at 29 US and 17 international centers using PDR CB units from two CB banks.

RESULTS

Transplant characteristics were as follows: median age, 3.5 years (range, 0.1-14 years); median patient weight, 15 kg (range, 4-61 kg); 58% male; HLA matches (intermediate-resolution HLA-A and HLA-B and high-resolution HLA-DRB1) of the units used in these patients six of six in 26, five of six in 48, four of six in 47, and three of six or two of six in 6; median prefreeze total nucleated cell dose, 10.5×10(7)/kg; median prefreeze CD34+ dose, 3.7×10(5)/kg; and nonmyeloablative regimen in 24%. The median times to myeloid and platelet engraftment were 21 and 49 days, respectively. The cumulative incidence of reported Grade II to IV acute graft-versus-host disease (aGVHD) was 38±5%, and 19±4% had Grade III to IV aGVHD. The Kaplan-Meier estimates of 3-year transplant-related mortality, overall survival, and disease-free survival were 20±4, 79±4, and 70±6%, respectively.

CONCLUSION

These data demonstrate the effectiveness of PDR CB units for HCT.

Cord blood transplantation and stem cell regenerative potential

The past 20 years of experience with umbilical cord blood transplantation have demonstrated that cord blood is effective in the treatment of a spectrum of diseases, including hematological malignancies, bone marrow failure, hemoglobinopathies, and inborn errors of metabolism. Cord blood can be obtained with ease and then safely cryopreserved for either public or private use without loss of viability. As compared to other unrelated donor cell sources, cord blood transplantation allows for greater human leukocyte antigen disparity without a corresponding increase in graft-vs.-host disease. Moreover, cord blood has a lower risk of transmitting infections by latent viruses and is less likely to carry somatic mutations than other adult cells. Recently, multiple populations of stem cells with primitive stem cell properties have been identified from cord blood. Meanwhile, there is an increasing interest in applying cord blood mononuclear cells or enriched stem cell populations to regenerative therapies. Accumulating evidence has suggested functional improvements after cord blood transplantation in various animal models for treatments of cardiac infarction, diabetes, neurological diseases, etc. In this review, we will summarize the most recent updates on clinical applications of cord blood transplantation and the promises and limitations of cell-based therapies for tissue repair and regeneration.

Cord blood banking in France: reorganising the national network

Paradoxically, France is one of the leading exporters of cord blood units worldwide, but ranks only 17th in terms of cord blood units per inhabitant, and imports 64% of cord blood grafts to meet national transplantation demands. With three operational banks in 2008, the French allogeneic cord blood network is now entering an important phase of development with the creation of seven new banks collecting from local clusters of maternities. Although the French network of public banks is demonstrating a strong commitment to reorganise and scale up its activities, the revision of France's bioethics law in 2010 has sparked a debate concerning the legalisation of commercial autologous banking. The paper discusses key elements for a comprehensive national plan that would strengthen the allogeneic banking network through which France could meet its national medical needs and guarantee equal access to healthcare.

Umbilical cord blood transplantation for non-malignant diseases

Many factors, including lower risk of GVHD, rapid availability of 4/6-6/6 matched cord blood (CB) units and incremental gains in the outcomes, have led to an increasing use of CB transplantation (CBT) to treat many patients who lack fully matched adult BM donors. A large electronically searchable worldwide inventory of publicly banked CB units allows for quicker donor identification and selection. In this review, we examine the current status and cumulative experience of related and unrelated donor CBT for the treatment of non-malignant diseases, including hemoglobinopathies, BM failure syndromes, primary immunodeficiency diseases (PIDs) and inherited metabolic disorders (IMDs), and conclude that CBT offers a promising and effective therapy for these diseases. Future strategies to facilitate earlier diagnosis and to decrease transplant-related risks should further improve the short- and long-term outcomes. Every effort should be made to perform transplantation early in the course of disease before extensive damage to various tissues and organs ensues.

Stem cells and the frontiers of neonatology

The aim of the most recent studies on regenerative medicine was to focus on capability of stem cells deriving not only from haematopoietic system, but also from other organ and tissues, to regenerate damaged tissues. Stem cells derived from foetal annexes such as cord blood, placenta and amniotic fluid can be currently used in the effort to treat prenatally diagnosed genetic diseases. Cells derived from cord blood have been used since 1988 as an alternative source to realize stem cell transplantation. Compared with bone marrow, cord blood has shown the advantages of quick availability, less risk of GHVD, together with higher compatibility rates, and less risk of infections. Mesenchymal stem cells (MSCs) are multi-potent stem cells able to differentiate into different lineages, including osteocytes, chondrocytes, and adipocytes. Because of their trafficking capacity to injured tissues, clinical trials have been started evaluating the use of MSCs in the treatment of metabolic diseases like Hurler syndrome and metachromatic leukodystrophy, or Osteogenesis Imperfecta. MSCs were initially identified in adult bone marrow (BM-MSC), but cells resembling BM-MSCs have also been found in other tissues, both adult (peripheral blood, synovial membrane) and foetal (peripheral blood, liver, spleen, placenta, umbilical cord, and amniotic membrane). BM-MSCs have been widely used in clinical applications, as for cell-based therapy of Osteogenesis Imperfecta and metabolic diseases. In addition, human multi-potent MSCs present in second-trimester amniotic fluids may be a good target for prenatal gene therapy because of their expandability, their ability to differentiate into multiple lineages and their high transduction efficiency.

Characterization of natural killer and natural killer-like T cells derived from ex vivo expanded and activated cord blood mononuclear cells: implications for adoptive cellular immunotherapy

OBJECTIVE

Cord blood (CB) is limited by the absence of available donor effector cells for post-unrelated CB transplantation adoptive cellular immunotherapy. We reported the ability to ex vivo expand (EvE) CB mononuclear cells (MNC) after short-term incubation with anti-CD3, interleukin (IL)-2, IL-7, and IL-12 (antibody/cytokine [AB/CY]) into subpopulations of CD3(-)/56(+) natural killer (NK) cells with enhanced in vitro and in vivo tumor cytotoxicity.

MATERIALS AND METHODS

We compared 2- vs 7-day EvE of rethawed CB MNCs in AB/CY and activation of NK and NK-like T (NKT) cell (CD3(+)/56(+)) subsets expressing specific NK-cell receptors along with IL-15, IL-18, and interferon-gamma production.

RESULTS

Nonadherent total cell number were significantly increased at day 7 (p<0.001) along with NK-cell number (20-fold) and an enrichment in NKT-like subsets (36-fold). There was no change in the NK(dim) subset; yet the NKT(bright) and NKT KIR3DL1(dim) subsets were significantly increased (p<0.05). NK cells expressing the inhibitory natural cytoxicity receptor CD94/NKG2A were decreased (p<0.001), while those expressing activating natural cytoxicity receptor CD94/NKG2D receptor and activating NK and NKT KIR2DS4 subsets were significantly increased (p<0.001). IL-18 and interferon-gamma protein production was also significantly increased (p<0.001 and p<0.05, respectively). Lysosomal-associated membrane protein-1 and granzyme B expression were increased (p<0.001 and p>0.01, respectively), which correlated with the significant increase in NK, LAK, and tumor cytotoxicity of the EvE cells.

CONCLUSION

This study demonstrates that previously cryopreserved and rethawed CB MNCs can be EvE up to 7 days to yield viable and activated NK and NKT-like subsets that appear to be cytolytic based on the cell repertoire and could be utilized in the future as adoptive cellular immunotherapy post-unrelated CB transplantation.