Outcomes Of Cord Blood Transplantation Research Articles

Effect of IL-2 polymorphism rs2069762 on single-unit cord blood transplant outcomes

BackgroundInterleukin-2 (IL-2) is one of the most important cytokines that regulate the activation and proliferation of T cells and natural killer cells. The production of IL-2 may be affected by polymorphisms in the promoter region of the IL-2 gene (rs2069762). In allogeneic hematopoietic cell transplantation (HCT) from adult donors, rs2069762 has been associated with the incidence of acute and chronic graft-versus-host disease (GVHD). However, the impacts of IL-2 polymorphism on cord blood transplantation (CBT) outcomes remain unclear. ObjectiveThe objective of this study was to assess the impact of IL-2 polymorphism rs2069762 on transplant outcomes, such as hematopoietic recovery, GVHD, overall survival, relapse, and non-relapse mortality (NRM) after CBT. Study DesignWe conducted a retrospective analysis of data from adult patients who underwent single-unit CBT at our institution from November 2005 to March 2023 for whom DNA samples from recipients and donors were available. IL-2 genotyping was performed using real-time polymerase chain reaction with the TaqMan® SNP genotyping assay for rs2069762. ResultsA total of 143 recipient and donor pairs were included in this study. The proportion of recipient IL-2 polymorphism rs2069762 was 48 % (n = 69) for AA, 42 % (n = 60) for CA, and 10 % (n = 14) for CC. The proportion of donor IL-2 polymorphism rs2069762 was 43 % (n = 61) for AA, 48 % (n = 69) for CA, and 9 % (n = 13) for CC. In the multivariate analysis, the use of an rs2069762 CA + CC donor was associated with lower neutrophil recovery compared to an rs2069762 AA donor (hazard ratio [HR], 0.66; 95 % confidence interval [CI], 0.50–0.88; P = 0.004). Furthermore, recipients of rs2069762 CA + CC were associated with higher NRM compared to recipients of rs2069762 AA (HR, 2.32; 95 % CI, 1.01–5.34; P = 0.047). Serum IL-2 levels at 8 weeks were significantly higher in rs2069762 CA + CC recipients compared to those with rs2069762 AA recipients (P = 0.014). ConclusionOur data showed that donor IL-2 polymorphism affects neutrophil recovery and recipient IL-2 polymorphism affects NRM in adults undergoing single-unit CBT. The polymorphism of IL-2 rs2069762 in recipients and donors might be associated with the clinical outcomes of single-unit CBT.

Updated comparable efficacy of cord blood transplantation for chronic myelomonocytic leukaemia: a nationwide study.

Chronic myelomonocytic leukaemia (CMML) is a haematological malignancy with a poor prognosis. Allogeneic haematopoietic stem cell transplantation remains the only curative approach. Without human leucocyte antigen-matched related sibling donors, the optimal alternative donor has yet to be established. Although unrelated bone marrow transplantation (UBMT) has been extensively studied, cord blood transplantation (CBT) for CMML remains largely unexplored. This nationwide retrospective study compared the outcomes of UBMT and single-unit umbilical CBT in patients with CMML. This study included 118 patients who underwent their first allo-HSCT during 2013-2021. Of these, 50 received BMT (UBMT group), while 68 underwent CBT (CBT group). The primary endpoint was the 3-year overall survival (OS). There were comparable 3-year OS rates between the UBMT (51.0%, 95% confidence interval [CI]: 34.1-65.5%) and CBT (46.2%, 95% CI: 33.2-58.1%; P = 0.60) groups. In the inverse probability of treatment weighting analysis, CBT did not show significantly improved outcomes compared with UBMT regarding the 3-year OS rate (hazard ratio 0.97 [95% CI: 0.57-1.66], P = 0.91). Thus, CBT may serve as an alternative to UBMT for patients with CMML. Further research is necessary to optimise transplantation strategies and enhance outcomes in patients with CMML undergoing CBT.

Comparison of fludarabine-based conditioning regimens in adult cord blood transplantation for myeloid malignancy: A retrospective, registry-based study.

Fludarabine/busulfan and fludarabine/melphalan are viable options as conditioning regimens. However, the optimal fludarabine-based conditioning in cord blood transplantation (CBT) remains unclear. Therefore, this retrospective, registry-based study aimed to analyze the impact of five fludarabine-containing conditioning regimens on 1395 adult patients (median age, 61 years) with acute myeloid leukemia, myelodysplastic syndrome, and chronic myeloid leukemia who underwent their first CBT. Treatment outcomes of fludarabine combined with melphalan (100-140 mg/m2 ) and low-dose total body irradiation (TBI; FM140T); melphalan (80-99 mg/m2 ) and TBI (FM80T); busulfan (12.8 mg/kg) and melphalan (FB4M); busulfan (12.8 mg/kg) and TBI (FB4T); and busulfan (6.4 mg/kg) and TBI (FB2T) were compared. The 3-year survival rate was 67%, 53%, 44%, 36%, and 39%, respectively (p < .0001). The FM140T survival rate was the most favorable after adjusting for confounders, and the hazard ratios (vs. FM140T) for overall mortality were as follows: FM80T, 1.6 (95% confidence interval [CI], 1.2-2.2); FB4M, 2.1 (95% CI, 1.6-2.8); FB4T, 2.7 (95% CI, 2.0-3.7); and FB2T, 2.2 (95% CI, 1.6-3.1). The better survival observed with FM140T, regardless of the disease, disease risk, age, or transplant year, was attributed to the lower relapse rate and lower non-relapse mortality (NRM) associated with fewer infectious deaths. Conversely, FB4T was associated with a higher relapse rate and higher NRM. The findings indicate that the outcomes of CBT in myeloid malignancies were highly dependent on both the alkylating agent and its dose in combination with fludarabine. Therefore, compared with fludarabine/busulfan-based conditioning, FM140T may be the preferred regimen.

The HLA-B Leader MM Genotype Has a Negative Impact on Outcomes in HLA-B One Antigen Mismatched and HLA-B Matched Cord Blood Transplantation without Anti-Thymocyte Globulin: Analysis of the Japanese Society for Transplantation and Cellular Therapy

Background: The dimorphism at position -21 of exon 1 in HLA-B gives rise to leader peptides featuring either methionine (M) or threonine (T) as the second residue in the processed leader peptide (HLA-B leader). The cell surface abundance of HLA-E is positively correlated with the copy number of −21M HLA-B. In hematopoietic cell transplantation (HCT), the MM genotype in the recipients is associated with worse outcomes after HLA-matched and mismatched unrelated bone marrow and peripheral blood stem cell transplantation compared with TT (Kanaya M, et al. ASH Annual Meeting 2021, Petersdorf EW et al. Lancet Haematol. 2020 and Blood. 2020). Eurocord/EBMT study revealed HLA-B leader mismatch in HLA-B mismatched combination is associated with relapse and non-relapse mortality (NRM) risks after cord blood transplantation (CBT) (Petersdorf EW et al. Haematologica 2021). Notably, approximately 70% of patients in the literature administrated anti-thymocyte globulin (ATG) for graft-versus-host disease (GVHD) prophylaxis. The impacts of HLA-B leader dimorphism on the outcomes of CBT still needed to be elucidated more. Particularly, we were interested in the significance of HLA-B leaders in CBT without an ATG, then we conducted a retrospective study to elucidate it. Methods: Clinical data of 10,569 patients who underwent single-unit CBT for acute myeloid leukemia (AML, n=5,518), myelodysplastic syndrome (MDS, n=1,483), acute lymphoblastic leukemia (ALL, n=2,020), and lymphoma (n=1,548) between 2008 - 2021 were provided by the Japanese Data Center for Hematopoietic Cell Transplantation. HLA-A, -B, -C, and -DRB1 typing was performed at least at the antigen level. The leader genotype is defined based on the two HLA-B allotypes. All patients were not used ATG for GVHD prophylaxis. Study outcomes were overall survival (OS), cumulative incidences of relapse, NRM, and grade II-IV acute GVHD (aGVHD). Multivariable Cox regression analysis including covariables; disease risk index (DRI), myeloablative/reduced-intensity conditioning, presence of total body irradiation as a conditioning regimen, short-term methotrexate or mycophenolate mofetil for GVHD prophylaxis, recipient cytomegalovirus serostatus. All statistical analyses were performed with EZR. Results: The median patient's age was 53 (range 0-88) years. The numbers of patients with HLA-B leader TT, MT, and MM genotype were 7,639 (72.3 %), 2,707 (25.6 %), and 223 (2.1 %), respectively. To classify HLA-B match/mismatch status, we stratify “HLA-B one locus mismatched (GVH direction)” and HLA-B matched (no GVH direction mismatch)“. First, we focused on HLA-B one antigen mismatched (HLA 5/6 antigen matched, n = 1172) setting as shown in the previous literature. Recipient MM genotype showed significantly worse OS and relapse in the multivariate analysis compared to MT or TT genotype (Tx) (Figure) (OS: hazard ratio [HR] 0.543 [95% CI, 0.311 - 0.947]; p = 0.032, relapse: [HR] 2.863 [95% CI, 1.330 - 6.165]; p = 0.007). Recipient MM didn't relate to relapse and grade II-IV aGVHD. Next, we explored the impacts of HLA-B leaders in HLA-B antigen-matched CBT (3/6 - 6/6 matched, n = 3995). Donor MM genotype demonstrated a negative impact for OS and NRM, not relapse and aGVHD, compared to Tx donor (Figure) (OS: [HR] 0.738 [95% CI, 0.542 - 1.000]; p 0.050, NRM: [HR] 1.695 [95% CI, 1.097 - 2.621]; p = 0.018). Especially, OS and NRM of donor MM genotype were significantly inferior to Tx in HLA 6/6 matched (n = 914) CBT (OS: [HR] 0.311 [95% CI, 0.187 - 0.518]; p &amp;lt; 0.001, NRM: [HR] 3.216 [95% CI, 1.931 - 5.356]; p = 0.034). Conclusions: ATG would affect immune dynamics strongly in CBT via in-vivo T cell depletion, yet the current study demonstrated the HLA-B leader was still a significant risk factor in CBT without ATG for the first time. Recipient MM genotype in HLA-B one locus mismatched (HLA 5/6 matched) and donor MM genotype in HLA-B matched were the risk factors for worse CBT outcomes. We concluded MM genotype donors would be avoided to decrease NRM in HLA-B matched CBT. The precise mechanism of negative impact in CBT outcomes in patients or donor MM genotype remains to be clarified, however, we assume higher level HLA-E expression may be crucial in terms of NKG2A inhibitory signaling to T cells/NK cells and T-cell direct recognition for peptide/HLA-E complex in CBT.

Single CBT As 2nd Allo-SCT Is Promising for Selected Patients with Relapsed Hematopoietic Malignancies

Background: Hematopoietic malignancies that relapse after allogeneic stem cell transplantation (allo-SCT) generally have a poor prognosis, and there is no standard treatment. Second allo-SCT is a potentially curative treatment, but many patients do not receive 2nd allo-SCT at the best time because of the long preparation time for transplantation, and even if they do, treatment-related complications and relapse of the underlying disease often lead them to fatal outcomes. Umbilical cord blood is considered to be a promising source of 2nd allo-SCT because of its short preparation time, rapid and high graft-versus Leukemia (GVL) effect after transplantation, and better response to GVHD treatment compared to other donor sources. Therefore, we investigated the usefulness of cord blood transplantation for relapsed hematopoietic malignancies after allo-SCT. Methods: We retrospectively analyzed the outcomes of patients with hematopoietic malignancies who received single cord blood transplantation (CBT) as 2nd allo-SCT for relapse after allo-SCT in Toranomon Hospital between Apr. 1999 and Mar. 2022. We exclude the patients with Eastern Cooperative Oncology Group (ECOG) performance status(PS) of 4. Results: 263 patients were included in this study. There were 179 patients with myeloid neoplasms and 84 with lymphoid neoplasms. Median age was 45 years (range: 18-71). 239 patients were in non-remission and 24 in remission before SCT. Median interval between 1st SCT and 2nd SCT was 293 days (26-4703). Donor sources of 1st allo-SCT were related donor in 80, unrelated donor in 62, and sCBT in 121 patients. 135 patients received myeloablative conditioning for 2nd allo-SCT, and 128 patients underwent reduced intensity-conditioning. About cord blood as the donor source of 2nd allo-SCT, the median total nucleated cell count at cryopreservation was 2.71(×10 7)/kg (1.67-5.85), and median CD34 + cell count at cryopreservation was 0.97(×10 5)/kg (0.25-3.18). Median observation period of survivors was 1726 (122-6286) days after 2nd allo-SCT. Overall survival (OS), non-relapse mortality and relapse at 2-year were 16.7%, 46.9% and 40.6%, respectively. Younger patients (&amp;lt; 50 years) had significantly better OS than older patients (50 years and more), with 2-year OS of 21.5% and 9.9%, respectively (P &amp;lt; 0.001). Patients with good PS (0 and 1) had significantly better survival than those with poor PS(2 and 3), with 2-year OS of 23.4% and 2.4%, respectively (P&amp;lt;0.001). Patients with myeloid malignancies tended to have better survival than those with lymphoid malignancies, with 2-year survival rates of 19.2% and 11.9%, respectively (P=0.341). Patients with longer interval between SCTs (&amp;gt;1 year) had significantly better survival than those with shorter interval (&amp;lt;1 year), with 2-year OS of 23.6% and 11.6%, respectively (P=0.00443). In multivariate analysis, younger age (&amp;lt;50), good PS (0-1), long interval between SCTs(≧1 year) showed a superior OS. In the younger age population, patients with myeloid neoplasms showed a superior OS compared to those with lymphoid neoplasms (2yrOS: 30.3% vs 10.6%, P=0.00318). Furthermore, patients with myeloid neoplasms having good PS and long interval between SCTs showed an extremely high survival rate of 50.5% at 2 years (n=31)(Figure 1). In the elderly population, patients with long interval and good PS showed a relatively good OS of 31.4% at 2 years (n=28)(Figure 2). The type of disease (myeloid vs lymphoid) didn't have a significant influence on OS in this subpopulation (28.1% vs 50.0%, P=0.129). Conclusion: Although the outcomes of CBT as 2nd allo-SCT haven't been satisfactory, there are certain populations, including elderly patients, with favorable OS.

UM171 Expanded Cord Blood Transplantation Outcomes Compare Favorably to All Different Stem Cell Sources: An EBMT Registry Case-Control Analysis

Background: Cord blood (CB) transplantation (CBT) has several advantages compared with other graft sources, such as permissive human leucocyte antigen (HLA) mismatches, and low risk of chronic graft-versus-host disease (GVHD) and relapse. However, CBT has fallen into disfavor because of its high risk of non-relapse mortality (NRM) and prolonged hospitalization due to its low cell dose. Furthermore, the need for the rare large cord bloods (CBs) leads to selection of poorly HLA-matched CBs, known to further increase NRM. UM171 is a small molecule that expands hematopoietic stem cells. A phase I-II study of a single UM171-expanded, myeloablative and reduced intensity CBT for patients with high-risk hematologic malignancies who lacked a donor, demonstrated prompt neutrophil engraftment, the ability to use smaller, better HLA-matched CBs, and a low NRM of 5% (Cohen S et al. Lancet Haematol 2020). The aim of the current analysis was to compare outcomes after a UM171 CBT to real-world cohorts of 6 other stem cell sources identified in the European Society for Blood and Marrow Transplantation (EBMT) registry. Methods: This is a retrospective study comparing 22 adults who received a single UM171-expanded CBT in the phase I-II study between 2016-2018, to 6 cohorts of patients allografted from different stem cell sources and reported to the EBMT registry. Control patients were eligible if they had received a myeloablative or reduced intensity allogeneic transplant for a hematologic malignancy in Europe during 2010-2021, were between the ages of 18-65 years, and had a Karnofsky performance status (KPS) score ≥70. The different donor control cohorts were: 1) CB, single or double units, with a calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF) for GVHD prophylaxis, 2) 10/10 HLA-matched unrelated donor (MUD) peripheral blood stem cells (PBSC) with a CNI and MMF or methotrexate (MTX), 3) 10/10 MUD bone marrow (BM) with a CNI and MMF or MTX, 4) 9/10 HLA-MUD BM or PBSC (9/10 UD), 5) T cell replete haploidentical donor (haplo) BM or PBSC, and 6) matched sibling donor (MSD) BM or PBSC. Exclusion criteria included in vitro manipulated grafts and CBT recipients who received anti-thymocyte globulin or alemtuzumab. Patients were directly matched for disease and status at transplant and propensity score matching was used for prior allograft, age, KPS, and conditioning regimen. Endpoints included engraftment, GVHD, NRM, relapse, progression-free survival (PFS), overall survival (OS), and GVHD-free relapse-free survival (GRFS). The EBMT attempted to identify 3 controls for each patient. If no control was identified for a UM171 patient, the latter was excluded from the analysis. Results: Between 17 and 21 UM171 CB patients were compared to 36 to 62 controls depending on the donor group as 1-3 controls could not be identified for each patient (Table 1). Median follow-up for the UM171 group was 36 months and generally longer for the controls. Neutrophil engraftment with UM171 CB was similar to all donor groups except slower for CB and MUD BM. Platelet engraftment was consistently slower for UM171 CB except when compared to conventional CB. The incidence of severe acute GVHD was similar across all donor groups. As there was no severe chronic GVHD in the UM171 group, the latter was associated with less extensive/severe chronic GVHD compared to MUD (PBSC and BM) and MSD. There was a trend towards lower NRM for UM171 CB compared to haplo and 9/10 UD but it did not reach statistical significance. PFS, OS and GRFS were all better with UM171 CB compared to haplo. Finally, GRFS was improved with UM171 CB when compared to MUD PBSC (Figue 1), 9/10 UD, and MSD. Conclusions: This registry matched case-control analysis demonstrated real-word evidence suggesting UM171-expanded CBT recipients have improved outcomes compared to other donor types. More specifically and due to the absence of severe chronic GVHD with UM171 CB, GRFS was better with UM171 CB when compared to other graft sources except for CB and MUD BM. Also, OS and PFS were superior with UM171 CB compared to haplo donors. Limitations of this study included the small number of UM171 patients, the inability to identify controls for each case, and certain missing data for the controls. UM171 expansion of CB appeared to achieve the desired outcome of maintaining benefits of CB while removing its disadvantages. Thus, prospective randomized studies are warranted to confirm these results.

The Outcomes of Cord Blood Transplantations Infused with Higher Total Number of Nucleated Cells Were Equivalent to Unrelated Bone Marrow Transplantations

Introduction: Choosing a suitable donor is essential to achieve a good response for allogeneic hematopoietic cell transplantation (allo-HCT). Several previous studies have compared unrelated bone marrow transplantation (UR-BMT) and cord blood transplantation (CBT), but the results differed among each study, and their superiority has been controversial. The total number of nucleated cells (TNC) in cord blood unit is crucial for CBT to avoid early complications, including engraftment failure. The outcome of CBT may improve by choosing cord blood unit with a higher TNC. Methods: We retrospectively compared the outcomes of CBT with higher TNC (hCBT) and UR-BMT conducted in our institute from January 1st, 2013, to May 31st, 2023. Cut off point of TNC was the median value. The primary endpoint was overall survival (OS), and the secondary endpoints were non-relapse mortality (NRM), cumulative incidence of relapse, and cumulative incidence of complications. Results: We analyzed a total of 316 patients, including 139 patients who underwent CBT and 177 patients who received UR-BMT. The median infused TNC was 2.71 (range, 0.027-6.42) ×10^7/kg. hCBT group included 69 patients. Significantly more patients in the hCBT group had prior allo-HCTs (hCBT: 18.8%, UR-BMT: 5.6%, p=0.003), and hCBT procedures were more frequently conducted since 2018 (hCBT: 66.7%, UR-BMT: 36.7%, p&amp;lt;0.001). For each group, most patients received tacrolimus and short-term methotrexate as graft-versus-host disease prophylaxis (hCBT: 94.2%, UR-BMT: 95.5%, p=0.277). ABO matched donors were more commonly chosen for UR-BMT (hCBT: 24.6%, UR-BMT: 46.3%, p=0.006). Patients with myelodysplastic syndrome underwent UR-BMT more frequently (hCBT: 7.2%, UR-BMT: 20.9%). Patients with a high or very high disease risk index were more frequently included in the hCBT group (hCBT: 37.5%, UR-BMT: 27.9%, p=0.060). Patient sex, age, days from diagnosis to transplantation, and hematopoietic cell transplantation comorbidity index, conditioning intensity were well balanced between each group. The two-year OS of hCBT was equivalent to UR-BMT (hCBT: 53.6%, UR-BMT: 58.9%, p=0.56) (Figure 1). There was no significant difference in the two-year NRM between the two groups (hCBT: 24.9%, UR-BMT: 25.4%, p=0.87). The hCBT group had a lower neutrophil engraftment rate achieved at day 28 (hCBT: 83.0%, UR-BMT: 92.3%, p&amp;lt;0.001). The two-year relapse rate was similar between the hCBT and UR-BMT groups (hCBT: 26.1%, UR-BMT: 18.7%, p=0.34). The cumulative incidence of acute GVHD tended to be lower in the hCBT group (hCBT: 18.2%, UR-BMT: 33.6% at 100 days, p=0.067), and the same results were observed when analyzing grade 2-4 or grade 3-4 acute GVHD. The cumulative incidence of chronic GVHD was significantly lower in the hCBT group (hCBT: 4.7%, UR-BMT: 48.3%, p&amp;lt;0.001), and the cumulative incidence of severe chronic GVHD was also lower in hCBT group (hCBT: 0.0%, UR-BMT: 13.9%, p&amp;lt;0.001). To reduce the impact of patients' characteristics, propensity score matching was conducted. The covariates included prior allo-HCTs, disease risk index, and allo-HCT conducted before 2018 or not. After propensity score matching, a total of 116 patients were included in the analysis with 58 patients for each group. The two-year OS of hCBT was also equivalent to UR-BMT (hCBT: 61.8%, UR-BMT: 55.2%, p=0.43) (Figure 2). The two-year NRM was slightly lower in hCBT group, but it is not significant (hCBT: 19.1%, UR-BMT: 30.1%, p=0.21). The hCBT group had a late neutrophil engraftment (hCBT: 87.0%, UR-BMT: 89.1% at day 28, p&amp;lt;0.001). The two-year relapse rate was similar between the hCBT and UR-BMT groups (hCBT: 25.0%, UR-BMT: 20.0%, p=0.54). The cumulative incidence of acute GVHD was tended to be lower in hCBT group (hCBT: 19.8%, UR-BMT: 38.7% at 100 days, p=0.057) and the cumulative incidence of chronic GVHD was significantly lower in hCBT group (hCBT: 5.3%, UR-BMT: 56.3%, p&amp;lt;0.001). Discussion: This was the first study to validate that the outcomes of CBT with higher TNC were equivalent to UR-BMT. Although the hCBT group experienced later neutrophil engraftment, the rate of neutrophil engraftment achieved at day 28 was comparable to UR-BMT, and a lower incidence rate of chronic GVHD might be attributed to lower NRM. From these findings, hCBT may be a worth considering option for patients requiring allo-HCT.

Efficacy of Cord Blood Transplantation for the Management of Chronic Myelomonocytic Leukemia: A Registry-Based Study in Japan

Introduction Chronic myelomonocytic leukemia (CMML) is a challenging malignancy that shares characteristics with myelodysplastic syndromes and myeloproliferative neoplasms. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative option for CMML. Numerous studies have examined transplant outcomes and prognostic factors; however, the focus has primarily been on bone marrow transplantation (BMT) and peripheral blood stem cell transplantation, while cord blood transplantation (CBT) is understudied. To address this knowledge gap, we conducted a nationwide retrospective study to comprehensively compare the outcomes of unrelated BMT and single-unit umbilical CBT in patients with CMML. Methods Data were collected from the Transplant Registry Unified Management Program 2 of the Japanese Data Center for Hematopoietic Cell Transplantation. The inclusion criteria were as follows: age of 16 years or higher, a diagnosis of CMML, and receipt of the first allo-HSCT between 2013 and 2019 through unrelated BMT from a human leukocyte antigen (HLA) 8/8-matched donor (UBMT group) or single-unit umbilical CBT (CBT group). The primary endpoint was overall survival (OS) after allo-HSCT, and the secondary endpoints included progression-free survival (PFS), cumulative incidences of relapse and non-relapse mortality (NRM), neutrophil engraftment, and graft-versus-host (GVHD)-free, relapse-free survival (GRFS). The impact of CBT versus unrelated BMT on outcomes was evaluated using inverse probability of treatment weighting (IPTW) analysis. In this analysis, the Cox proportional hazards regression model for OS, PFS, and GRFS and the Fine-Gray proportional hazards regression model for relapse, NRM, engraftment, and GVHD were used. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for all outcomes. The propensity score (PS) was calculated via logistic regression by using the following factors: age at allo-HSCT, sex, cytogenetic risk, disease status, days from diagnosis to allo-HSCT, and year of allo-HSCT. For the CBT group, the stabilized weights were calculated by dividing CBT prevalence by each individual's PS. Conversely, for the UBMT group, the weights were calculated by dividing the 1 minus prevalence of CBT by 1 minus each individual's PS. Results Between 2013 and 2021, 238 patients with CMML underwent their first allo-HSCT. Among them, 50 underwent HLA 8/8 allele-matched unrelated BMT (UBMT group) and 68 underwent single-unit umbilical CBT (CBT group). The median age at allo-HSCT was 58.5 (range: 26-75) years; the median follow-up period for survivors was 1,329.5 (range: 100-1,967) days. Intergroup differences in age at allo-HSCT, recipient sex, hematopoietic cell transplantation-specific comorbidity index, Eastern Cooperative Oncology Group performance status, cytogenetic risk, pre-transplant treatment, disease status at allo-HSCT, conditioning intensity, GVHD prophylaxis, and year of allo-HSCT were not significant. The transplantation outcomes are shown in Figure 1. There were no significant differences in the 3-year OS rate (UBMT: 51.0% [95% CI: 34.1-65.5%] vs CBT: 46.2% [95% CI: 33.2-58.1%]; P = 0.60; Figure 1A). IPTW analysis revealed no significant differences between the CBT and UBMT groups (HR: 1.21, 95% CI: 0.69-2.10, P = 0.51). PFS, relapse, NRM, and GRFS were not significantly different between the groups (Figure 1B-E). The neutrophil engraftment rate at 30 days was significantly higher in the UBMT group than in the CBT group (UBMT: 92.0% [95% CI: 78.9-97.1%] vs CBT: 79.4% [95% CI: 67.5-87.4%]; P &amp;lt; 0.01; Figure 1F). These observations associated with the secondary endpoints were concurrently corroborated by the IPTW analysis. Conclusion Our study suggests that CBT can serve as a viable treatment option, demonstrating efficacy comparable to that of unrelated BMT for patients with CMML. These findings underscore the improved outcomes over time after CBT in patients with CMML, which is a treatment previously perceived as inferior to other donor sources (Itonaga et al., Biol Blood Marrow Transplant. 2018;24:840-48). Further investigations are warranted to optimize transplantation strategies and improve outcomes in patients with CMML.

Advantages of Higher Busulfan Dose Intensity in Fludarabine-Combined Conditioning for Patients with Acute Myeloid Leukemia Undergoing Cord Blood Transplantation

The alkylating agent busulfan is commonly used as conditioning in allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia (AML). However, a consensus has not yet been reached regarding the optimal busulfan dose in cord blood transplantation (CBT). Therefore, we conducted this large nationwide cohort study to retrospectively analyze the outcomes of CBT in patients with AML receiving busulfan at intermediate (6.4 mg/kg i.v.; BU2) or higher (12.8 mg/kg i.v.; BU4) doses within a fludarabine/i.v. busulfan (FLU/BU) regimen. Among 475 patients who underwent their first CBT following FLU/BU conditioning between 2007 and 2018, 162 received BU2 and 313 received BU4. Multivariate analysis identified BU4 as a significant factor for longer disease-free survival (hazard ratio [HR], .85; 95% confidence interval [CI], .75 to .97; P=.014) and a lower relapse rate (HR, .84; 95% CI, .72 to .98; P=.030). No significant differences were observed in non-relapse mortality between BU4 and BU2 (HR, 1.05; 95% CI, .88-1.26; P=.57). Subgroup analyses showed that BU4 provided significant benefits for patients who underwent transplantation while not in complete remission (CR) and those age <60 years. Our present results suggest that higher busulfan doses are preferable in patients undergoing CBT, particularly those not in CR and younger patients.

Unrelated Donor Cord Blood Transplantation in Children: Lessons Learned Over 3 Decades

Four decades ago, Broxmeyer et al. demonstrated that umbilical cord blood (CB) contained hematopoietic stem cells (HSC) and hypothesized that CB could be used as a source of donor HSC for rescue of myeloablated bone marrow. In 1988, Gluckman et al. reported the first successful matched sibling cord blood transplant (CBT) in a child with Fanconi Anemia. In 1991, Rubinstein et al. established an unrelated donor CB bank, and in 1993, the first unrelated CBT used a unit from this bank. Since that time, >40 000 CBTs have been performed worldwide. Early outcomes of CBT were mixed and demonstrated the importance of cell dose from the CB donor. We hypothesized that improvements in CB banking and transplantation favorably impacted outcomes of CBT today and performed a retrospective study combining data from Eurocord and Duke University in 4834 children transplanted with a single unrelated CB unit (CBU) from 1993 to 2019. Changes in standard transplant outcomes (overall survival [OS], disease free survival [DFS], acute and chronic graft-versus-host disease [GvHD], treatment related mortality [TRM], and relapse) over 3 time periods (1: <2005; 2: 2005 to <2010; and 3: >2010 to 2019) were studied. Increased cell dose and degree of HLA matching were observed over time. OS, times to engraftment, and DFS improved over time. The incidence of TRM and GvHD decreased while the incidence of relapse remained unchanged. Relative contributions of cell dose and HLA matching to transplant outcomes were also assessed and showed that HLA matching was more important than cell dose in this pediatric cohort.

Adverse effect of donor-specific anti-human leukocyte antigen (HLA) antibodies directed at HLA-DP/-DQ on engraftment in cord blood transplantation

Background aimsWhile donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) in the recipient before transplantation are associated with graft failure in cord-blood transplantation (CBT), effects of DSAs other than against HLA-A, -B or -DRB1 on transplantation outcomes remained poorly understood. MethodsWe retrospectively analyzed 567 single-unit CBT recipients to evaluate impact of DSAs against HLA-DP and -DQ on CBT outcomes. ResultsAmong 143 recipients (25.2%) who had anti-HLA antibodies, nine harbored DSAs against HLA-DP or -DQ. DSAs against HLA-DP or -DQ were associated with a significantly lower neutrophil engraftment rate (55.6% versus 91.8%, P = 0.032) and with a marginally lower platelet engraftment rate (46.7% versus 75.3%, P = 0.128) at day 100 after transplantation, compared with patients without anti-HLA antibodies. Time to neutrophil and platelet engraftment in patients with DSAs for HLA-DP or -DQ was significantly longer than that in patients without anti-HLA antibodies (median, 25 versus 21 days, P = 0.002 in neutrophil; median 61 versus 46 days, P = 0.014 in platelet). Cumulative incidence of bacterial infection at day 100 was significantly greater (88.9% versus 57.1%, P = 0.024), and re-transplant-free survival was marginally lower (55.6% versus 76.8%, P = 0.132) in patients with DSAs against HLA-DP or -DQ, compared with those without anti-HLA antibodies. These findings suggest that DSAs against HLA-DP or -DQ lead to unfavorable engraftment, which may increase risk of bacterial infection, and reduce survival soon after CBT. ConclusionsOur results suggest the importance of evaluating DSAs against HLA-DP and -DQ in recipients before selecting CB units.

Role of NK cells in cord blood transplantation and their enhancement by the missing ligand effect of the killer-immunoglobulin like receptor.

Natural killer (NK) cells are the first lymphocytes reconstituted after allogenic hematopoietic stem cell transplantation (HSCT). Especially, in cord blood transplantation (CBT), the increase in the number of NK cells is sustained for a long period. Although there are conflicting results, many studies show that early reconstitution of NK cells is associated with favorable CBT outcomes, suggesting that maximizing NK cell functions could improve the CBT outcome. Killer immunoglobulin-like receptors (KIRs) include inhibitory and stimulatory receptors, which can regulate NK-cell activity. Because some of the KIRs have HLA class I as their ligand, the KIR-ligand interaction on NK cells can be lost in some cases of CBT, which results in the activation of NK cells and alters HSCT outcome. Thus, effects of KIR-ligand mismatch under various conditions have been widely examined; however, the results have been controversial. Among such studies, those using the largest number of CBTs showed that HLA-C2 (KIR2DL1-ligand) mismatches have a favorable effect on the relapse rate and overall survival only when the CBT used methotrexate for graft-versus-host disease prophylaxis. Another study suggested that KIR-ligand mismatch is involved in reducing the relapse of acute myeloid leukemia, mediated by reactivation of cytomegalovirus. These results indicate that activation of NK cells by KIR-ligand mismatch may have favorable effects on CBT outcomes and could help enhance the NK-cell function.

Reducing Mortality of Single-Unit Unrelated Cord Blood Transplantation for Relapsed Acute Myeloid Leukemia after a Previous Allogeneic Transplantation: A Real-World Retrospective Study Over the Past 19 Years in Japan

Relapse is the most common cause of treatment failure after allogeneic hematopoietic cell transplantation (HCT) for acute myeloid leukemia (AML). Second or subsequent allogeneic HCT using unrelated cord blood has been performed for adult patients with AML who have relapsed after a previous allogeneic HCT. Although outcomes after unrelated cord blood transplantation (CBT) as the first allogeneic HCT have significantly improved in recent years, it is unclear whether survival and engraftment improve after CBT as the second or subsequent allogeneic HCT for adult AML patients relapsing after a previous allogeneic HCT. The objective of this retrospective study was to evaluate trends of survival and other transplantation outcomes after single-unit unrelated CBT as a second or subsequent allogeneic HCT in adult patients with relapsed AML after a previous allogeneic HCT over the past 19 years in Japan. We retrospectively assessed survival trends and other outcomes of single-unit unrelated CBT as a second or subsequent allogeneic HCT in adult patients with relapsed AML after a previous allogeneic HCT according to the time period of CBT (2001-2007, 2008-2013, or 2014-2019) using a nationwide Japanese database. The median age was 45 years among 1109 CBTs, and 844 (78.6%) patients were not in complete remission at the time of CBT. Over the 3 time periods, there was a progressive increase in higher cryopreserved cord blood total nucleated cell dose and myeloablative conditioning regimens. The 2-year overall survival was 14.0% in 2001-2007, 19.9% in 2008-2013, and 24.4% in 2014-2019 (P <.001 by log-rank trend test). The 2-year relapse-related mortality was 54.0% in 2001-2007, 44.4% in 2008-2013, and 39.1% in 2014-2019 (P < 0.001 by Gray's test), but nonrelapse mortality was not significantly different across the time periods (P=0.557 by Gray's test). The 42-day neutrophil engraftment also significantly improved (62.9% in 2001-2007, 69.7% in 2008-2013, and 79.9% in 2014-2019; P < 0.001 by Gray's test). Our data demonstrate significant improvements in overall and relapse-related mortality, as well as neutrophil engraftment, after single-unit unrelated CBT as a second or subsequent allogeneic HCT for adult patients with AML relapsed after previous allogeneic HCT over the past 19 years.

Single-Nucleotide Polymorphisms Within Non-HLA Regions Are Associated With Engraftment Effectiveness for Patients With Unrelated Cord Blood Transplantation.

Clinically, stem cells with matched human leukocyte antigens (HLAs) must be selected for allogeneic transplantation to avoid graft rejection. However, adverse reactions still occur after cord blood transplantation (CBT). It was inferred that the HLA system is not the only regulatory factor that may influence CBT outcomes. Therefore, we plan to investigate whether the single-nucleotide polymorphisms (SNPs) located in non-HLA genes are associated with the effectiveness of CBT. In this study, the samples of 65 donors from CBT cases were collected for testing. DNA sequencing was focused on the SNPs of non-HLA genes, cytotoxic T-lymphocyte-associated protein 4 (CTLA4), CD28, tumor necrosis factor ligand superfamily 4 (TNFSF4), and programmed cell death protein 1 (PDCD1), which were selected in regard to the literatures published in 2017 and 2018, which indicated that they were related to stem cell transplantation. Then, in combination with the detailed follow-up transplantation tracking database, these SNPs were analyzed with the risk of mortality, relapse, cytomegalovirus (CMV) infection, and graft-versus-host disease (GVHD). We found that there were 2 SNPs of CTLA4, 1 SNP of TNFSF4, and 2 SNPs of PDCD1 associated with the effectiveness of unrelated CBT. These statistically significant SNPs and haplotypes would be used in clinical to choose the best donor for the patient receiving CBT. Moreover, the polygenic risk scores (PRSs) with these SNPs could be used to predict the risk of CBT adverse reactions with an area under the receiver operating characteristic curve (AUC) of 0.7692. Furthermore, these SNPs were associated with several immune-related diseases or cancer susceptibility, which implied that SNPs play an important role in immune regulation.

Improved trends in survival and engraftment after single cord blood transplantation for adult acute myeloid leukemia

Unrelated cord blood transplantation (CBT) is an alternative curative option for adult patients with acute myeloid leukemia (AML) who need allogeneic hematopoietic cell transplantation (HCT) but lack an HLA-matched related or unrelated donor. However, large-scale data are lacking on CBT outcomes for unselected adult AML. To investigate the trends of survival and engraftment after CBT over the past 22 years, we retrospectively evaluated the data of patients with AML in Japan according to the time period of CBT (1998–2007 vs 2008–2013 vs 2014–2019). A total of 5504 patients who received single-unit CBT as first allogeneic HCT for AML were included. Overall survival (OS) at 2 years significantly improved over time. The improved OS among patients in ≥ complete remission (CR)3 and active disease at CBT was mainly due to a reduction of relapse-related mortality, whereas among patients in first or second CR at CBT, this was due mainly to a reduction of non-relapse mortality. The trends of neutrophil engraftment also improved over time. This experience demonstrated that the survival and engraftment rate after CBT for this group has improved over the past 22 years.

Coexistence of HLA and KIR ligand mismatches as a risk factor for viral infection early after cord blood transplantation.

Viral infection is one of the lethal adverse events after cord blood transplantation (CBT). Human leukocyte antigen (HLA) and killer immunoglobulin-like receptor (KIR) ligand divergences can increase the risk of viral infection due to conflicting interactions between virus-infected cells and immune cells. However, the relationship between these disparities and the frequency of viral infection after CBT remains to be evaluated. Herein, we have conducted a retrospective multicenter study to assess the effect of HLA and KIR ligand mismatches on viral infections after CBT. The study included 429 patients, among which 126 viral infections occurred before day 100. Viral infection was significantly associated with poorer overall survival (OS; hazard ratio [HR] 1.74, p < 0.01). Patients harboring ≥3 mismatches in the HLA allele and inhibitory KIR ligand mismatches (HLA & KIR mismatches) had a significantly greater prevalence of viral infection (HR 1.66, p = 0.04). Thus, patients with HLA & KIR mismatches had poorer outcomes in terms of non-relapse mortality (HR 1.61, p = 0.05). Our study demonstrates the unfavorable impacts of HLA & KIR mismatches on viral infections and non-relapse mortality after CBT. Evaluating the viral infection risk and performance of an appropriate and early intervention in high-risk patients and optimizing the graft selection algorithm could improve the outcome of CBTs.

ABO incompatibility does not affect transfusion requirements or clinical outcomes of unrelated cord blood transplantation after myeloablative conditioning for haematological malignancies.

The effects of ABO incompatibility on cord blood transplantation (CBT) have not been confirmed. We retrospectively investigated the effect of ABO incompatibility on the clinical outcomes and changes of isoagglutinin titres of 261 consecutive patients who underwent CBT in a single centre. We studied patients with haematological malignancies undergoing unrelated CBT following myeloablative conditioning. There were 80 matched, 72 major mismatched, 72 minor mismatched, and 37 bidirectional mismatched transplants. Risk factors that could potentially influence the patients' outcomes were evaluated. Immunoglobulin M (IgM) isohaemagglutinin antibody (IHA) titres were determined 1 day before and 2, 4, 6 and 8 weeks after the transplant. ABO mismatches did not influence engraftment, transfusion requirements, event-free survival or overall survival following CBT. The anti-donor IgM serum IHA titres fell to ≤1:8 at week 8 after CBT in all patients with ABO major and bidirectional mismatches. The percentages of patients requiring platelet and red blood cell transfusions in the period 31-61 days after CBT were markedly lower than in the period 0-30 days after CBT, being 15 vs 99% for platelets and 23 vs 78% for red blood cells, respectively. Of the 69 recipients of minor mismatched CBT tested, only three with AB blood type developed low titres of anti-recipient IHA after 5 months. In this study ABO incompatibility did not affect clinical outcomes after CBT. A higher number of CD34+ cells infused was correlated with earlier engraftment. Severe acute graft-versus-host disease was associated with poor overall survival. As the IHA titre decreased, so did the number of patients requiring blood transfusion. Rapidly decreasing anti-donor IHA titres and the non-production of donor anti-recipient A and/or B antibodies might contribute to a good outcome of ABO-incompatible CBT with myeloablative conditioning for haematological malignancies.

Durable outcomes of double cord blood transplantation in adults with acute lymphoblastic leukemia: high-risk features for early and long-term mortality.

Background:Cord blood transplantation (CBT) has been reported as an acceptable option with comparable outcomes to conventional donors in adults with acute lymphoblastic leukemia (ALL). We aimed to analyze the long-term CBT outcomes and risk factors for early and long-term mortalities.Methods:Between 2006 and 2020, 112 patients (median age: 35 years; 62 Ph-negative ALL and 50 Ph-positive ALL) were treated with double CBT. Conditioning regimen consisted of total body irradiation (12 Gy) plus cytarabine (9.0 g/m2) plus fludarabine (150 mg/ m2), and graft-versus-host disease (GVHD) prophylaxis was attempted by administering tacrolimus plus mycophenolate mofetil.Results:The median time for neutrophil and platelet recovery was 25 days (range: 5–59 days) and 34 days (range: 7–185 days), respectively. The cumulative incidence of acute GVHD at 1 year was 43.8%, and the incidence of acute GVHD with grades III–IV was 8.9%. The overall cumulative incidence of chronic GVHD was 22.0%, and the incidence of moderate to severe chronic GVHD was 8.5%. After a median follow-up of 60.1 months (range: 5.7–181.3 months), the 5-year cumulative incidence of relapse (CIR) and nonrelapse mortality (NRM) were 15.9% and 28.5% (9.7% and 27.2% for CR1), respectively, and the 5-year overall survival (OS) was 57.9% (66.5% for CR1). In multivariate analysis of 88 patients receiving double CBT in CR1, delayed CR1 was related to high CIR, and age older than 40 years was associated with high NRM and early mortality. Unexpectedly, Ph-positive ALL with MRD had a higher NRM and early mortality than Ph-negative ALL and Ph-positive ALL without MRD subgroups, possibly due to delayed neutrophil and platelet recovery.Conclusion:Our data suggest that double CBT for adult ALL in CR1 has a greater benefit in younger patients and in patients with Ph-positive ALL without MRD or Ph-negative ALL.

Clinical outcome of cord blood transplantation for nine children with juvenile myelomonocytic leukemia receiving fludarabine-busulfan-cyclophosphamide-based conditioning.

Juvenile myelomonocytic leukemia (JMML) is a rare hematological malignancy in young children and can only be cured through the allogeneic stem cell transplantation. We have retrospectively analyzed the outcomes of nine children with JMML after unrelated cord blood transplantation (UCBT). Eight patients who have received a myeloablative conditioning regimen of fludarabine (FLU), busulfan (BU), and cyclophosphamide (CY) have gotten engraftment. None of the nine patients has relapsed following initial UCBT. Six patients are still alive and in complete remission after UCBT with a median observation time of 43months (range: 10-80months). This study shows that UCBT with FLU-BU-CY conditioning regimen can represent a suitable option for children with JMML.

Haploidentical Versus Cord Blood Stem Cell Transplantation As the Second Transplant for Relapsed Acute Myeloid Leukemia Patients after the First Stem Cell Transplantation

Haploidentical Versus Cord Blood Stem Cell Transplantation As the Second Transplant for Relapsed Acute Myeloid Leukemia Patients after the First Stem Cell Transplantation