Aim of this study was to compare the outcomes of transplantation by donor source and to help select the best alternative donor in children with leukemia. Donor sources included matched related donor (MRD, n = 35), allele-matched unrelated donor (M-UD, n = 10) or -mismatched (MM)-UD (n = 13) or unrelated umbilical cord blood (UCB, n = 11). UCB group had a significantly higher incidence of grade II-IV acute graft versus host disease (MRD, 11.8%; M-UD, 30.0%; MM-UD, 15.4%, UCB, 54.4%, P = 0.004) but there was no difference in incidence of chronic graft versus host disease between 4 groups. The 5-yr leukemia-free survival (LFS) was 76.7%, 60.0%, 69.2%, and 45.5%, respectively (P = 0.128). MRD group showed higher LFS rate than UCB group (P = 0.022). However, LFS of M-UD and MM-UD together (65.2%) was not different from that of MRD group (76.7%, P = 0.325), or from that of UCB (45.5%, P = 0.190). The relapse incidence at 5 yr was 17.1%, 20.0%, 15.4%, and 0%, respectively (P = 0.460). The 100-day treatment-related mortality was 2.9%, 20.0%, 7.7%, and 36.4%, respectively (P = 0.011). Despite the limitations of small number of patients, unrelated donor transplants including even allele-mismatched ones, seem to be as effective in children with leukemia lacking suitable relative donors. Also, UCB transplant may serve as another possible option in urgent transplants.
Allogeneic Hematopoietic Stem Cell Transplantation; Leukemia; Unrelated Donor; Umbilical Cord Blood
We assessed the combination of sirolimus, tacrolimus and low-dose methotrexate as acute graft versus host disease prophylaxis after reduced intensity conditioning allogeneic peripheral blood stem cell transplantation from matched related (MRD, n=46) and unrelated (URD, n=45) donors. All patients received fludarabine and intravenous busulfan conditioning followed by transplantation of mobilized peripheral blood stem cells. The median time to neutrophil engraftment was 13 days. The cumulative incidence of grade II–IV and III–IV acute GVHD were 16% and 7%, respectively. There was no difference in the incidence of acute GVHD between MRD and URD cohorts. Two year cumulative incidence of extensive chronic GVHD was 40%. Relapse-free survival at two years was 34%: 21% in MRD and 45% in URD. Overall survival at two years was 59%: 47% in MRD and 67% in URD. High levels (>90%) of donor derived hematopoiesis were achieved in 59% of patients early after transplantation. The addition of sirolimus to tacrolimus and low-dose methotrexate as GVHD prophylaxis following reduced intensity conditioning with fludarabine and low dose intravenous busulfan is associated with rapid engraftment, low rates of acute GVHD, and achievement of high levels of donor chimerism.
As success of reduced intensity conditioning (RIC) hematopoietic stem cell transplantation (HSCT) relies primarily on graft-versus-leukemia (GVL) activity, increased minor HLA disparity in unrelated compared to related donors could have a significant impact on transplant outcomes. To assess whether use of unrelated donors (URD) engenders more potent GVL in RIC HSCT compared to matched related donors (MRD), we retrospectively studied 433 consecutive T-replete 6/6 HLA matched URD (n= 246) and MRD (n=187) RIC HSCT for hematologic malignancies at our institution. Diseases included: AML(127), NHL(71), CLL (68), MDS (64), HD(40), CML (25), MM(23), MPD (12), ALL(7), other leukemia (1). All received uniform fludarabine and intravenous busulfan conditioning, and GVHD prophylaxis with tacrolimus/mini-MTX or tacrolimus/sirolimus +/− mini-MTX. Unrelated donors were younger compared to MRD (median age: 33 yrs vs. 52 yrs, p<0.0001), and provided larger CD34+ products (median CD34+ cells infused: 8.7 × 106/kg vs. 7.5 × 106/kg, p=0.002). Distribution of diseases, disease risk, prior transplant, and CMV status was similar in both cohorts. Cumulative incidence of grade II–IV acute GVHD (at day+180), 2 year-chronic GVHD, and 2-year non-relapse mortality (NRM) were 20% vs. 16%, 55% vs. 50%, and 8% vs. 6% in URD and MRD, respectively (p=NS). Cumulative incidence of relapse at 2 years was lower in URD, 52% vs. 65% (p=0.005). With median follow-up of 26.5 and 35.8 months, 2-yr progression free survival (PFS) was significantly better in unrelated donor transplants, 39.5% for URD and 29% for MRD (p= 0.01). Overall survival at 2 years were 56% for URD vs. 50% for MRD (p=0.53). In multivariable analysis, URD was associated with a lower risk of relapse (HR 0.67, p =0.002) and superior PFS (HR 0.69, p=0.002). These results suggest that URD is associated with greater GVL activity than MRD, and could have practice changing impact on future donor selection in RIC HSCT.
The lower morbidity and mortality of reduced-intensity conditioning (RIC) regimens have allowed allogeneic hematopoietic cell transplantation (HCT) in older patients. Unrelated umbilical cord blood (UCB) has been investigated as an alternative stem cell source to suitably HLA matched related (MRD) and adult volunteer unrelated donors. We hypothesized that RIC HCT using UCB would be safe and efficacious in older patients and compared the transplant related mortality (TRM) and overall survival of RIC HCT in patients older than 55 years using either MRD (n=47) or, in patients with no 5/6 or 6/6 HLA compatible related donors, UCB (n=43). RIC regimen consisted of total-body irradiation (200 cGy) and either cyclophosphamide and fludarabine (n=69), or busulfan and fludarabine (n=16) or busulfan and cladribine (n=5). The median age of MRD and UCB cohorts was 58 (range, 55-70) and 59 (range, 55-69) years, respectively. AML/MDS (50%) was the most common diagnosis. All MRD grafts were 6 of 6 HLA matched to the recipient. Among patients undergoing UCB HCT, 88% received two UCB units to optimize cell dose and 93% received 1-2 HLA mismatched grafts. The median followup for survivors was 27 (range, 12-61) months. The 3-year probabilities of progression-free survival (30% vs. 34%, p=0.98) and overall survival (43% vs. 34%, p=0.57) were similar for recipients of MRD and UCB. The cumulative incidence of grade 2-4 acute graft-versus-host disease (42% vs. 49%, p=0.20) and TRM at 180-days (23% vs. 28%, p=0.36) were comparable. However, UCB recipients had a lower incidence of chronic graft-versus-host disease at 1-year (40% vs. 17%, p=0.02). On multivariate analysis, graft type had no impact on TRM or survival and HCT comorbidity index score was the only factor independently predictive for these endpoints. Our study supports the use of HLA mismatched UCB as an alternative graft source for older patients who need a transplant but do not have a MRD. The use of RIC and UCB extends the availability of transplant therapy to older patients previously excluded on the basis of age and lack of a suitable MRD. A careful review of existing comorbidities is necessary when considering older patients for HCT.
Allogeneic Stem Cell Transplantation; Umbilical Cord Blood Transplantation; Non-myeloablative Conditioning Regimen; Reduced Intensity Conditioning Regimen
For adults with high-risk or recurrent acute lymphoblastic leukemia (ALL) who lack a suitable sibling donor, the decision between autologous (Auto) and unrelated donor (URD) hematopoietic stem cell transplantation (HSCT) is difficult due to variable risks of relapse and treatment-related mortality (TRM). We analyzed data from two transplant registries to determine outcomes between Auto and URD HSCT for 260 adult ALL patients in first (CR1) or second (CR2) complete remission. All patients received a myeloablative conditioning regimen. The median follow-up was 77 (range 12-170) months. TRM at 1 year post-transplant was significantly higher with URD HSCT; however, there were minimal differences in TRM according to disease status. Relapse was higher with Auto HSCT and was increased in patients transplanted in CR2. Five year leukemia-free (37% vs. 39%) and overall (38% vs. 39%) survival rates were similar for Auto HSCT vs. URD HSCT in CR1. There were trends favoring URD HSCT in CR2. The long follow-up in this analysis demonstrated that either Auto or URD HSCT can result in long-term leukemia free and overall survival for adult ALL patients. The optimal time (CR1 vs. CR2) and technique to perform HSCT remains an important clinical question for adult ALL patients.
acute lymphoblastic leukemia (ALL); adult; autologous HSCT; unrelated donor HSCT
Umbilical cord blood (UCB) has gradually emerged over the last decade as an alternative source of hematopoietic cells for transplantation in children and adults with high-risk or advanced hematological malignancies who do not have a suitably matched related or unrelated adult donor. This increase in use of UCB is due to favorable results in children, growing availability of UCB units with large cell doses, less stringent donor-recipient HLA matching and rapid identification and acquisition of the unit. In children with acute leukemia, the data support similar leukemia-free survival after transplantation of HLA-matched and 1 or 2 HLA-mismatched UCB and HLA-matched unrelated donor bone marrow. In adults with acute leukemia, some reports suggest a survival advantage after transplantation of matched unrelated bone marrow compared to UCB and others, similar leukemia-free survival. Work is in progress to improve hematopoietic recovery and lower early transplant-related deaths, the two major limitations to a successful outcome after UCB transplant. The importance of HLA-matching and cell dose on outcomes after UCB transplantation support the need for an even greater investment in public cord blood banks. Simultaneously searching of accredited cord blood banks and bone marrow donor registries for patients without an HLA-matched sibling thought to benefit from hematopoietic stem cell transplantation is encouraged.
A majority of adult patients with acute lymphoblastic leukemia (ALL) will die of their disease. While the prognosis for pediatric patients is markedly better, in all cases, the prognosis in patients with relapsed or refractory disease is uniformly poor. Allogeneic hematopoietic stem cell transplantation (HSCT) from a related donor can offer a significant potential therapeutic benefit for some patients. Since most patients lack a suitable related donor, alternative allo-HSCT approaches, including unrelated, umbilical cord blood (UCB), and haploidentical allo-HSCT, have been developed and are increasingly being studied in the clinical setting. Reduced-intensity conditioning further extends access to allo-HSCT for older more comorbid patients. While the use of donor-derived T cell adoptive therapy has a uniformly dismal outcome in patients with relapsed ALL following HSCT, modified adoptive T cell regimens, including the infusion of enriched tumor-targeted donor T cells and genetically targeted T cells, are currently under clinical investigation with promising results. Lastly, natural killer (NK) cells genetically modified to target ALL are also being studied in clinical trials, further expanding therapeutic options for patients with refractory or relapsed ALL. What remains to be seen is whether these novel adoptive cell therapies will ultimately lead to improved clinical outcomes.
Acute lymphoblastic leukemia; adoptive cellular therapy; hematopoietic stem cell transplants; chimeric antigen receptor
Umbilical cord blood (UCB) has been used successfully as a source of hematopoietic stem cells (HSCs) for allogeneic transplantation in children and adults in the treatment of hematologic diseases. However, compared with marrow or mobilized peripheral blood stem cell grafts from adult donors, significant delays in the rates and kinetics of neutrophil and platelet engraftment are noted after UCB transplant. These differences relate in part to the reduced numbers of HSCs in UCB grafts. To improve the rates and kinetics of engraftment of UCB HSC, several strategies have been proposed, including ex vivo expansion of UCB HSCs, addition of third-party mesenchymal cells, intrabone delivery of HSCs, modulation of CD26 expression, and infusion of two UCB grafts. This article will focus on ex vivo expansion of UCB HSCs and strategies to enhance UCB homing as potential solutions to overcome the problem of low stem cell numbers in a UCB graft.
cord blood transplantation; CXCR4; engraftment; ex vivo expansion; hematopoietic stem cell; Notch; SDF-1; stem cell homing; umbilical cord blood
Hematopoietic cell transplantation (HCT) from a matched related donor (MRD) benefits many adults with acute myeloid leukemia (AML) in first complete remission (CR1). The majority of patients do not have such a donor, however, requiring use of an alternative donor if HCT is undertaken. We retrospectively analyzed 226 adult AML CR1 patients undergoing myeloablative unrelated donor (URD) (10/10 match, n=62; ≤9/10, n=29) or MRD (n=135) HCT from 1996–2007. Five-year estimates of overall survival (OS), relapse, and non-relapse mortality (NRM) were 57.9%, 29.7%, and 16.0%, respectively. Failure for each of these outcomes was slightly higher for 10/10 URD than MRD HCT, although statistical significance was not reached for any endpoint. The adjusted hazard ratios (HR) were 1.43 (0.89–2.30, p=0.14) for overall mortality, 1.17 (0.66–2.08, p=0.60) for relapse, and 1.79 (0.86–3.74, p=0.12) for NRM, respectively, and the adjusted odds ratio (OR) for grades 2–4 acute graft-versus-host disease was 1.50 (0.70–3.24, p=0.30). Overall mortality among 9/10 and 10/10 URD recipients was similar (adjusted HR=1.16 [0.52–2.61], p=0.71). These data indicate that URD HCT can provide long-term survival for CR1 AML; outcomes for 10/10 URD HCT, and possibly 9/10 URD HCT, suggest that this modality should be considered in the absence of a suitable MRD.
acute myeloid leukemia (AML); first complete remission; hematopoietic stem cell transplantation; unrelated donor; matched related donor
We sought to better define the role of hematopoietic cell transplantation (HCT) in first remission (CR1) for high-risk pediatric acute myeloid leukemia (AML).
Outcomes were compared among patients aged less than 21 years with cytogenetically defined poor-risk AML treated with chemotherapy, matched related (MRD), or unrelated donor (URD) transplantation in CR1. Poor-risk cytogenetics was defined as monosomy 7/del7q, monosomy 5/del 5q, abnormalities of 3q, t(6;9)(p23;q34), or complex karyotype. Included are patients treated on Children’s Oncology Group trials or reported to the Center for International Blood and Marrow Transplant Research from 1989 to 2006.
Of the 233 patients, 123 received chemotherapy, 55 received MRD HCT, and 55 received URD HCT. The 5-year overall survival from the time of consolidation chemotherapy or transplant conditioning was similar: chemotherapy (43% ± 9%), MRD (46% ± 14%), or URD (50% ± 14%), P = 0.99. Similarly, multivariate analysis demonstrated no significant differences in survival [(reference group = chemotherapy); MRD HR 1.08, P = 0.76; URD HR 1.13, P = 0.67] despite lower relapse risk with URD HCT (HR = 0.43, P = 0.01).
Our findings do not provide support for the preferential use of HCT over chemotherapy alone for children with cytogenetically defined poor-risk AML in CR1.
acute myeloid leukemia; chemotherapy; hematopoietic cell transplantation; pediatrics
The incidence of excessive adiposity is increasing worldwide and is associated with numerous adverse health outcomes. We compared outcomes by body mass index (BMI) for adult patients with acute myeloid leukemia (AML) who underwent autologous (auto, n=373), related donor (RD, n=2041), or unrelated donor (URD, n=1801) allogeneic myeloablative hematopoietic cell transplantation (HCT) using marrow or peripheral blood stem cells reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) from 1995-2004. Four weight groups by BMI (kg/m2) were defined: underweight < 18; normal 18 – 25; overweight >25 – 30; and obese > 30. Multivariable analysis referenced to the normal weight group showed an increased risk of death for underweight patients in the RD group (RR, 1.92; 95% CI, 1.28-2.89; P = 0.002) but not in the URD group. There were no other differences in outcomes among the other weight groups within the other HCT groups. Overweight and obese patients enjoyed a modest decrease in relapse incidence, though this did not translate into a survival benefit. Small numbers of patients limit the ability to better characterize the adverse outcomes seen in the underweight RD but not the underweight URD allogeneic HCT patients. Obesity alone should not be considered a barrier to HCT.
Hematopoietic cell transplantation; obesity; outcomes; acute myeloid leukemia
During the past four decades, a substantial progress has been made in the field of hematopoietic stem cell transplantation (HSCT). From July, 2007 to December, 2010, a transplant survey from 42 HSCT units indicates that the types of transplantation performed are related identical (43%), related mismatched/haploidentical (28%), unrelated donor matched (11%), unrelated donor mismatched (7%), umbilical cord blood (UCB, 2%) and autologous (9%). The distribution of disease entities being transplanted in allogeneic settings is acute myeloid leukemia (AML) (34%), acute lymphoblastic leukemia(ALL) (24%), chronic myeloid leukemia (CML) (20%), myelodysplastic syndrome (MDS) (8%), aplastic anemia (AA) (7%), Mediterranean anemia (MIA) (2%), non-Hodgkin's lymphoma (NHL) (3%), and other diseases (3%). Clinical data from Peking University Institute of Hematology and other transplant centers suggest that haploidentical transplantation has been a choice of the best alternative source of stem cells for individual patients without matched sibling donors. A modified donor lymphocyte infusion (DLI) approach can be safely used for prophylaxis and treatment of leukemia relapse in patients with advanced leukemia following mismatched transplant. The number of transplants from unrelated donor or related mismatched/haploidentical donor has increased significantly during recent years. Double UCBT is a promising strategy for the therapy of hematological disease. In addition, mesenchymal stem cell (MSC) transplantation may be a potential therapeutic approach for treating systemic lupus erythematosus (SLE).
Hematopoietic; blood; stem cell; transplantation; HSCT; China; review
Transplantation of hematopoietic stem cells from an unrelated donor (URD) is an option for many patients who do not have an HLA-identical sibling donor (MSD). Current criteria for the selection of URDs include consideration for HLA alleles determined by high resolution typing methods, with preference for allele-matched donors. However, the utility and outcome associated with transplants from URDs compared with those from MSDs remains undefined.
Patients and Methods
We examined clinical outcome after patients received bone marrow transplants (BMTs) from MSDs; HLA-A, -B, -C, and DRB1 allele-matched URDs (8/8); and HLA-mismatched URDs in a homogeneous population of patients with chronic myeloid leukemia (CML) in first chronic phase (CP1) where a strong allogeneic effect and hence a lower risk of relapse is anticipated. Transplantation outcomes were compared between 1,052 URD and 3,514 MSD BMT recipients with CML in CP1.
Five-year overall survival and leukemia-free survival (LFS) after receipt of BMTs from 8/8 matched URDs were worse than those after receipt of BMTs from MSDs (5-year survival, 55% v 63%; RR, 1.35; 95% CI, 1.17 to 1.56; P < .001; LFS, 50% v 55%; RR, 1.21; 95% CI, 1.06 to 1.40; P = .006). Survival was progressively worse with greater degrees of mismatch. Similar and low risk of relapse were observed after receipt of transplant from either MSD or URD.
In this homogeneous cohort of good risk patients with CML in CP1, 5-year overall survival and LFS after receipt of transplant from 8/8 allele-matched donors were modestly though significantly worse than those after receipt of transplant from MSDs. Additive adverse effects of multilocus mismatching are not well tolerated and should be avoided if possible.
Analysis of hematopoietic cell transplantation (HCT) for high-risk or recurrent acute lymphoblastic leukemia (ALL) using different donor sources is confounded by variable conditioning and supportive care.
Patients and Methods
We studied 623 consecutive ALL myeloablative HCT (1980 to 2005). Donors were autologous (n = 209), related (RD; n = 245), unrelated (URD; n = 100), and umbilical cord blood (UCB; n = 69).
After median of 8.3 years of follow-up, 5-year overall survival (OS), leukemia-free survival (LFS), and relapse were 29% (95% CI, 26% to 32%), 26% (95% CI, 23% to 29%), and 43% (95% CI, 39% to 47%), respectively. Treatment-related mortality (TRM) at 2 years was 28% (95% CI, 25% to 31%). Mismatched URD sources yielded higher TRM (relative risk [RR], 2.2; P < .01) and lower OS (RR, 1.5; P = .05) than RD or UCB HCT. Autografting yielded significantly more relapse (68%; 95% CI, 59% to 77%; P < .01) and poorer LFS (14%; 95% CI, 10% to 18%; P = .01). HCT in first complete remission (CR1) yielded significantly better outcomes than later HCT. In a 1990 to 2005 allogeneic CR1/second complete response cohort, 5-year OS, LFS, and relapse rates were 41% (95% CI, 35% to 47%), 38% (95% CI, 32% to 44%), and 25% (95% CI, 19% to 31%), respectively; 2-year TRM was 34% (95% CI, 28% to 40%). With RD, well-matched URD and UCB sources, 5-year LFS was 40% (95% CI, 31% to 49%), 42% (95% CI, 14% to 70%), and 49% (95% CI, 34% to 64%), respectively, while relapse was 31% (95% CI, 22% to 40%), 17% (95% CI, 0% to 37%), and 27% (95% CI, 13% to 41%). Acute graft-versus-host disease was associated with fewer relapses. Since 1995, we noted progressive improvements in OS, LFS, and TRM.
Allogeneic, but not autologous, HCT for ALL results in durable LFS. Importantly, HCT using UCB led to similar outcomes as either RD or well-matched URD. HCT in early remission can best exploit the potent antileukemic efficacy of allografting from UCB, RD, or URD sources.
Allogeneic stem cell transplantation has continued to evolve as a common procedure for the treatment of hematological malignancies and bone marrow failure. Donor bone marrow and mobilized peripheral stem cells are routinely employed for the reconstitution of immune function in leukemia and lymphoma patients following radiation and/or chemotherapy. Unfortunately, only 30% of patients have an HLA identical sibling donor and the identification of matched unrelated donors, particularly for minorities, can present an exceptional challenge. The transplantation of umbilical cord blood (UCB) represents the most recent strategy to expand the potential donor pool while maintaining an acceptable level of treatment related complications. First utilized in children, UCB transplantation permits a higher degree of HLA disparity while demonstrating a reduction in the incidence and severity of graft versus host disease (GvHD) compared to previous transplantation modalities. Despite the apparent decrease in GvHD, relapse rates remain comparable to transplantation with bone marrow or mobilized peripheral blood suggesting a strong graft versus leukemia/lymphoma (GvL) effect. However, several issues complicate the use of UCB transplantation and its extension to the treatment of adults. Many infections that afflict transplant patients are particularly frequent and more severe in the context of UCB transplantation. UCB T cells are naïve and therefore display less proliferation and IFN-γ production in response to cognate antigen and also appear to demonstrate defects in signal transduction mechanisms. In addition, UCB contain T regulatory cells (Treg) with more potent suppressor function than adult Treg. Furthermore, adult patients often require more total cells and CD34+ progenitors for transplantation than a single UCB unit can provide. Thus, strategies to expand selected subpopulations from UCB and the use of multi-unit transplantation are areas of active research. This review will provide a condensed summary of the clinical history of UCB transplantation and emphasize the advantages and disadvantages of this approach to hematological malignancies in comparison to other methods of hematopoietic stem cell transplantation. Subsequently, it will mainly focus on the current challenges to immune reconstitution presented by UCB transplantation, recent research into their cellular and molecular mechanisms, and experimental approaches to overcome them.
Cord Blood transplantation; tolerance; immune reconstitution; post-transplant infections
Umbilical cord blood (UCB) is a source of primitive hematopoietic stem (HSC) and progenitor cells, that served as an alternative to bone marrow (BM) for effective transplantation therapy. Success of HSC transplantation (HSCT) is limited in part by graft-versus-host disease (GVHD), graft rejection and delayed immune reconstitution, which all relate to immunological complications. GVHD after UCB transplantation is lower compared to that of BM HSCT. This may relate to the tolerogenic nature of T cells, mononuclear cells (MNCs) and especially immune regulatory cells existing in UCB. UCB contains limiting numbers of HSC or CD34+ cell dose for adult patients resulting in delayed engraftment after UCB transplantation (UCBT). This needs to be improved for optimal transplantation outcomes. Approaches have been undertaken to promote HSC engraftment, including co-infusion of multiple units of UCB cells. These new methods however added additional immunological complications. Herein, we describe current knowledge on features of UCB immune cells, including regulatory T cells (Tregs) and mesenchymal stem/stromal cells (MSCs) and their potential future usage to reduce GVHD.
Cord blood Transplantation; Transplantation Tolerance; T-lymphocytes; Dendritic Cells; Regulatory T cells; Mesenchymal Stromal/Stem Cells; Natural Killer Cells
The impact of HLA matching on outcomes of unrelated donor (URD) hematopoietic stem cell transplantation (HSCT) varies in different racial or ethnic groups. Since little is known about the impact of such matching on URD HSCT in Korean children, we analyzed this issue.
We analyzed the outcomes of 142 patients who underwent URD HSCT at 4 Korean medical centers. All patient donor pairs were fully typed for HLA-A, -B, -C, and -DR alleles.
At a median follow-up of 22 months, 3-year survival rates for patients with 8, 7, and ≤6 matched alleles were 88.4%, 70.7%, and 53.6%, respectively. A single mismatch (Mm) at HLA-B or -C was associated with lower survival compared with that associated with 8 matched alleles. No significant differences were observed between single-allele and single-antigen Mms with respect to survival rate or acute graft-versus-host disease (aGVHD) incidence rates. HLA disparity had a greater impact on the survival of patients with high-risk malignancy than of those with low-risk malignancy. Among pairs with a single Mm, only locus A showed a significant association and higher risk of grade III-IV aGVHD compared to those in patients with 8 matched alleles.
Disparity in HLA class I, regardless of antigen or allele Mm, adversely affected both survival and grade III-IV aGVHD development. An increased number of HLA Mms was associated with a higher risk of post-transplantation complications. Further investigations using larger cohorts are required to confirm the effects of HLA mismatching on URD HSCT patient outcomes.
URD HSCT; HLA; Korean children
Allogeneic hematopoietic cell transplantation (HCT) recipients have substantial transfusion requirements. Factors associated with increased transfusions and the extent of blood product use in umbilical cord blood (UCB) recipients are uncertain. We reviewed blood product use in 229 consecutive adult recipients of allogeneic HCT at the University of Minnesota: 147 with leukemia, 82 lymphoma or myeloma; 58% received unrelated UCB and 43% sibling donor peripheral blood stem cell (PBSC) grafts. Although neutrophil recovery was prompt (UCB median 17, range 2–45 days, and PBSC 14, range 3–34 days), only 135 of 229 (59% cumulative incidence, CI) achieved RBC independence and 157 (69%) achieved platelet independence by 6 months. Time to platelet independence was prolonged in UCB recipients (median UCB 41 vs. PBSC 14 days) and in patients who had received a prior transplant (median 48 vs. 32 days). Patients who received UCB grafts required more RBC through day 60 post HCT (mean UCB 7.8 (95% CI 6.7–8.9) vs. PBSC 5.2 (3.7–6.7) transfusions, p=0.04), and more platelet transfusions (mean 25.2 (95% CI 22.1–28.2) vs. 12.9 (9.4–16.4), p<0.01) compared to PBSC recipients. Patient receiving myeloablative (MA) conditioning required more RBC and platelet transfusions during the first 2 months post HCT compared to reduced intensity conditioning (RIC) (7.4 vs. 6.2, p=0.3 for RBC; 23.2 vs 17.5, p=0.07 for platelets). Despite prompt neutrophil engraftment, UCB recipients had delayed platelet recovery as well as more prolonged and costly blood product requirements. Enhanced approaches to accelerate multilineage engraftment could limit the transfusion-associated morbidity and costs accompanying UCB allotransplantation.
Purpose of review
This review summarizes the state of the art of unrelated donor (URD) umbilical cord blood transplantation (UCBT) for the treatment of hematologic malignancies and discusses the current issues associated with the use of this hematopoietic stem cell (HSC) source.
In contrast to the very high transplant-related mortality associated with the early experience of UCBT, recent series have been associated with comparable survival to that of human leucocyte antigen-matched URD transplantation in children with similarly promising results in adults with the use of double-unit grafts. In addition, utilization of reduced-intensity conditioning regimens has been successful extending access to patients unsuitable for myeloablation. Consequently, the use of umbilical cord blood as a HSC source and the global inventory of units in public banks is rapidly increasing although challenges associated with engraftment, unit quality, and infectious complications remain and will be discussed in this review.
URD umbilical cord blood is an alternative HSC source offering a unique set of advantages and disadvantages as compared with the transplantation of HSC from unrelated volunteers. Improved transplant outcomes are now making UCBT a rival to URD transplantation for the treatment of hematologic malignancies.
allogeneic transplantation; cord blood; hematologic malignancy
Allogeneic hematopoietic cell transplantation can be curative for patients with high-risk acute leukaemia. Umbilical cord blood (UCB) is an increasingly used source of allogeneic stem cells for patients who are in need of a transplant, but do not have a sibling donor. This review highlights the similarities and differences between the natural killer (NK) cells obtained from adult peripheral blood (PB) and UCB. These two cell sources show similar percentages of NK cells, including the major CD56dim and CD56bright subpopulations. UCB also contains an additional CD56−CD16+ subset, not typically found in PB. In addition, there are a number of progenitor cell populations in UCB that can give rise to NK cells. Some studies showed that UCB NK cells express a relatively higher percentage of inhibitory receptors (CD94/NKG2A and killer-cell immunoglobulin-like receptors) and less adhesion molecules. Resting UCB NK cells also show significantly less cytotoxicity compared to PB NK cells. However, following cytokine stimulation, the cytotoxicity of UCB NK cells can be rapidly increased to levels that are comparable to PB NK cells. Activation and expansion protocols for UCB NK cells are briefly reviewed. Lastly, we outline the early use of UCB NK cells in clinical trials.
Umbilical cord blood; Natural killer (NK) cells; cytotoxicity; immunotherapy; expansion
This study was performed in order to evaluate the incidence and characteristics of cytomegalovirus (CMV) infection in children with acute leukemia according to donor source and graft type.
Materials and Methods
We retrospectively identified children with acute leukemia who had received allogeneic hematopoietic cell transplantation at Samsung Medical Center in Korea from October 1998 to December 2009.
In total, 134 recipients were identified. The patients were classified into the following three groups: unrelated cord blood (CB, n=36), related bone marrow or peripheral blood stem cells (RD, n=41), and unrelated bone marrow or peripheral blood stem cells (UD, n=57). The 365-day cumulative incidence of CMV antigenemia was not significantly different among the three groups (CB 67% vs. RD 49% vs. UD 65%, p=0.17). However, CB recipients had the highest median value of peak antigenemia (CB 160/2×105 leukocytes vs. RD 7/2×105 leukocytes vs. UD 19/2×105 leukocytes, p<0.01) and the longest duration of CMV antigenemia than the other stem cell source recipients (CB 87 days vs. RD 17 days vs. UD 28 days, p<0.01). In addition, the 730-day cumulative incidence of CMV disease was the highest in the CB recipients (CB 36% vs. RD 2% vs. UD 5%, p<0.01). Thirteen CB recipients developed CMV disease, in which five of them had more than one organ involvement. Two patients, who were CB recipients, died of CMV pneumonia.
This study suggests that CB recipients had both longer and higher cumulative incidences of CMV infection. Therefore, a more aggressive and effective strategy of CMV management should be considered in CB recipients.
CMV; cord blood; stem cell transplantation; leukemia
Use of umbilical unrelated cord-blood (UCB) cells as an alternative source of hematopoietic cell transplantation has been widely used mainly for patients lacking an HLA-matched donor. UCB present many advantages over bone marrow or mobilized peripheral blood from volunteer donors, such as rapid availability, absence of risk for the donor, and decreased incidence of acute graft-versus-host disease. However, a significant clinical problem is delayed engraftment that is directly correlated with the number of hematopoietic stem cells in a cord-blood unit. The identification of prognostic factors associated with engraftment that can be easily modified (e.g., strategies for donor choice) and the development of new approaches including use of multiple donors, intrabone injection of UCB, ex vivo expansion, and cotransplantation with accessory cells are of crucial importance in order to circumvent the problem of delayed engraftment after UCB transplantation. Those approaches may increase the quality and availability of UCB for transplantation.
Hematopoietic stem cell transplantation (HSCT) activity was surveyed in the 9 countries in the WHO Eastern Mediterranean (EM) region that are reported to carry out transplants. Between the years of 1984 and 2007, 7933 transplants were reported. The total number of HSCT per year has continued to increase, with a plateau in allogeneic HSCT (allo-HSCT) between 2005 and 2007. Overall, a greater proportion of transplants were allogeneic HSCT (allo-HSCT) (n=5761, 77%) compared to autologous HSCT (ASCT) (n=2172, 23% ASCT). Of 5761 allo-HSCT, acute leukemia constituted the main indication (n=2124, 37%). There was a relatively high proportion of allo-HSCT for bone marrow failure (n=1001, 17%) and hemoglobinopathies (n=885, 15%). The rate of unrelated donor transplants remained low, with only 2 non-umbilical cord matched unrelated donor (MUD) allo-HSCT reported. One hundred umbilical cord (UCB) transplants were reported (0.017% of allo- HSCT). Peripheral blood stem cells (PBSC) were the main source of graft in allo-HSCT, and PBSCT increasingly constitutes the main source of stem cells. Reduced intensity conditioning was utilized in 5.7% of allografts over the surveyed period. ASCT numbers continue to increase. There has been a shift in the indication for ASCT from acute leukemia to lymphoproliferative disorders (45%) followed by myeloma (26%). The survey reflects transplantation activity according to the unique health settings of this region. Notable differences in transplant practices as reported to the European Group for Blood and Marrow Transplantation (EBMT) over recent years are addressed.
Hematopoietic stem cell transplantation; EMRO; stem cell source; conditioning
Minimal residual disease (MRD), both before and after transplant, is a clinically important yet relatively poorly defined aspect of allogeneic hematopoietic stem cell transplantation (alloHSCT). The clinical relevance of MRD in the context of alloHSCT has been demonstrated by its association with the development of clinical relapse. However, with the possible exception of chronic myeloid leukemia, the specific techniques, timing, frequency and clinical utility, relative to improvement in patient outcomes, for monitoring MRD in the setting of alloHSCT has yet to be clearly defined. A concise overview of monitoring techniques for detecting MRD, as well as treatment strategies and biologic and clinical research initiatives for MRD suggested by the National Cancer Institute 1st International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation, is covered in this paper.
minimal residual disease; allogeneic; relapse; graft-versus-tumor; DLI
Purpose of Review
2008 marks the 20th anniversary of the first use of umbilical cord blood (UCB) as a source of donor cells for hematopoietic stem cell transplantation. In those early days, there was great doubt and skepticism about the utility of UCB as a source of hematopoietic stem cells. Doubts about whether UCB, containing 10-20x fewer cells than bone marrow, had sufficient cells to durably engraft a myeloablated patient and, after demonstration that engraftment occurred with less graft-versus-host disease (GvHD), whether it would confer graft versus leukemia (GvL) activity were raised.
Transplantation with UCB is effective in the treatment of children with hematological malignancies, marrow failure, immunodeficiencies, hemoglobinopathies and inherited metabolic diseases. Transplantation without full HLA matching is possible and despite a lower incidence of GvHD, GvL is preserved. The number of cells in a single UCB can be limiting, but the use of 2 UCBs for a single transplant shows promise to overcome this obstacle.
Cord blood transplantation is now an established field with enormous potential. UCB increases access to transplantation therapy for many patients unable to indentify a fully matched adult donor. In the future, it may emerge as a source of cells for cellular therapies focused on tissue repair and regeneration.
Umbilical Cord Blood; Unrelated Donors; Hematopoietic Stem Cell Transplantation; Inborn Errors of Metabolism