The use of haploidentical stem cell transplant as an alternative donor source in patients with decreased access to matched unrelated donors.

INTRODUCTION: The likelihood of finding HLA-matched unrelated donors for rare HLA types and non-white European ancestry continues to be a challenge with less than a 70% chance of finding a full match. Mismatched transplants continue to have high rates of transplant-related mortality. With the near-universal ability to find a haploidentical donor in families, haploidentical transplants have become of more critical importance in ethnic minority groups and patients with rare HLA types. METHODS: Data was collected through clinical trials, review articles, and case reports published in the National Library of Medicine. RESULTS: The use of improved lymphodepleting conditioning regimens, graft versus host disease (GVHD) prophylaxis using regimens such as post-transplant cyclophosphamide, mycophenolate, and tacrolimus have improved engraftment to nearly 100 percent and reduced transplant-related mortality to less than 20 percent. Attention to donor-specific antibodies (DSAs) with interventions using bortezomib, rituximab, and plasmapheresis has decreased graft failure rates. CONCLUSION: With improved prevention of GVHD with interventions such as post-transplant cyclophosphamide and management of DSAs, haploidentical transplants continue to improve transplant-related mortality (TRM) compared to patients who received matched-related donor transplants. While TRM continues to improve, ongoing research with haploidentical transplants will focus on improving graft and donor immunosuppression and identifying the best regimens to improve TRM without compromising relapse-free survival.

Why Altruistic Organ Donations Are Not Meeting Demands.

Solid-organ transplantation remains the optimal therapeutic option for end-stage organ disease. Altruistic donation represents the ultimate sign of generosity and the most important gift of life. Currently, <10% of the global needs for transplant are fulfilled. Organ shortages result from an inability to provide an adequate organ supply to match demands. The recently observed stagnation in living kidney donations in the United States is related to a drop in all types of organ donations from living related donors, which has been paralleled with a steady and continuous increase in all living unrelated donations. Some forms of living unrelated donation represent a financially driven survival system within which wealthy recipients exploit poor donors. Low rates of altruistic donation are related to cultural barriers, religious obstacles, fear, and consequent distrust in the system. The low rate indicates a state of lack of societal solidarity, a consequence of the state of subconsciousness at the individual and collective levels that humanity is living in. Human domestication, the conditioning process that humans go through since birth and the primary facilitator of this subconscious state, is guarded through familial, social, cultural, religious, political, and mass media organizations, which are all under the influence of the monetary establishment. Acquired beliefs, mainly during the domestication process, influence our perception of the environment, our values, and ultimately our way of life. Unfortunately, this conditioning process is negatively enforced, leading to a stressful state. The powerful subconscious mind places humans in a permanent survival mode, resulting in loss of intelligence, indispensable for well-being and happiness. Altruistic donation requires a close cooperation between all parties involved in the donation process and necessitates a positive reprograming of our subconscious based on sharing, generosity, satisfaction, gratitude, trust, inner peace, and ultimately happiness, well-known constituents of unconditional love, which represents the peak of consciousness.

Haploidentical and matched unrelated donor allogeneic hematopoietic stem cell transplantation offer similar survival outcomes for acute leukemia.

BACKGROUND: Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has emerged as an effective approach for acute leukemia, primarily due to the inherent difficulty in finding human leukocyte antigen-matched unrelated donors (MUD). Nevertheless, it remains uncertain whether haplo-HSCT and MUD-HSCT can provide comparable outcomes in patients with acute leukemia. AIMS: This study aimed to assess the overall survival (OS) and leukemia-free survival (LFS) outcomes between the MUD-HSCT and haplo-HSCT groups. METHODS AND RESULTS: This retrospective analysis encompassed adult patients with acute leukemia undergoing the initial allo-HSCT. Among these 85 patients, we stratified 33 patients into the MUD-HSCT group and 52 to the haplo-HSCT group. The primary outcomes were OS and LFS. The median OS was not reached in the haplo-HSCT group, while it reached 29.8 months in patients undergoing MUD-HSCT (p = .211). Likewise, the median LFS periods were 52.6 months in the haplo-HSCT group and 12.7 months in the MUD-HSCT group (p = .212). Importantly, neither the OS nor LFS showed substantial differences between the MUD-HSCT and haplo-HSCT groups. Furthermore, univariate analyses revealed that haplo-HSCT did not demonstrate a significantly higher risk of worse LFS (hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.38-1.25; p = .216) or OS (HR, 0.67; 95% CI, 0.36-1.26; p = .214) than MUD-HSCT. Notably, a high European Group for Blood and Marrow Transplantation risk score (HR, 1.44; 95% CI, 1.10-1.87; p = .007) and non-complete remission (HR, 2.48; 95% CI, 1.17-5.23; p = .017) were significantly correlated with worse OS. CONCLUSION: Haplo-HSCT may serve as an alternative to MUD-HSCT for the treatment of acute leukemia, offering similar survival outcomes.

[Haploidentical donor peripheral blood stem cell transplantation using third-party cord blood compared with matched unrelated donor transplantation for patients with hematologic malignancies].

Objectives: To assess the efficacy of cord blood-assisted haploid peripheral blood stem cell transplantation (haplo-cord-PBSCT) versus unrelated donor peripheral blood stem cell transplantation (UD-PBSCT) in the treatment of malignant hematological diseases. Methods: A retrospective analysis was performed on one hundred and four patients with malignant hematological diseases who underwent haplo-cord-PBSCT and fifty-two patients who underwent UD-PBSCT at Xiangya Hospital of Central South University between January 2016 and December 2021. Results: ①The median implantation time for neutrophils in the haplo-cord-PBSCT and UD-PBSCT groups was 13 (9-22) days and 13 (10-24) days, respectively (P=0.834), whereas the median implantation time for platelets was 15 (7-103) days and 14 (8-38) days, respectively (P=0.816). The cumulative implantation rate of neutrophils at 30 days after transplantation in the haplo-cord-PBSCT group and the UD-PBSCT group was 100% (P=0.314), and the cumulative platelet implantation rate at 100 days after transplantation was 95.2% (95% CI 88.3% - 98.1% ) and 100% (P=0.927), respectively. 30 days after transplantation, both groups of patients achieved complete donor chimerism, and no umbilical cord blood stem cells were implanted. ②The cumulative incidence rates of grade Ⅱ-Ⅳ acute GVHD within 100 days after transplantation in the haplo-cord-PBSCT group and the UD-PBSCT group were 29.1% (95% CI 20.1% -38.1% ) and 28.8% (95% CI 17.2% -41.6% (P=0.965), respectively. The cumulative incidence rates of grade Ⅲ/Ⅳ acute GVHD were 7.8% (95% CI 3.6% -14.0% ) and 9.6% (95% CI 3.5% -19.5% ) (P=0.725). The cumulative incidence rates of 2-year chronic GVHD in the haplo-cord-PBSCT group and the UD-PBSCT group were 45.3% (95% CI 36.1% -56.1% ) and 35.1% (95% CI 21.6% -44.1% ), respectively (P=0.237). The cumulative incidence rates of severe chronic GVHD at 2 years after transplantation were 13.6% (95% CI 7.6% -21.3% ) and 12.9% (95% CI 5.1% -24.3% ), respectively (P=0.840). ③The 2-year CIR after transplantation in the haplo-cord-PBSCT group and UD-PBSCT group were 12.8% (95% CI 7.0% -20.5% ) and 10.0% (95% CI 3.6% -20.2% ), respectively (P=0.341), and the NRM were 14.7% (95% CI 8.4% -22.6% ) and 16.2% (95% CI 7.4% -28.0% ), respectively (P=0.681). ④The 2-year OS rates in the haplo-cord-PBSCT and UD-PBSCT groups after transplantation were 82.2% (95% CI 74.8% -90.3% ) and 75.5% (95% CI 64.2% -88.7% ), respectively (P=0.276). The 2-year DFS rates were 69.9% (95% CI 61.2% -79.8% ) and 73.8% (95% CI 62.4% -87.3% ), respectively (P=0.551). The 2-year rates of GVHD-free/recurrence-free survival (GRFS) were 55.3% (95% CI 44.8% -64.8% ) and 64.7% (95% CI 52.8% -79.3% ), respectively (P=0.284) . Conclusion: The findings of this study indicate that haplo-cord-PBSCT and UD-PBSCT have comparable efficacy and safety in the treatment of malignant hematological diseases and can be used as an alternative treatment options.

Unrelated umbilical cord blood transplantation with low-dose anti-thymocyte globulin for children with severe aplastic anemia: A case series.

OBJECTIVE: This study aimed to investigate the prognosis of unrelated umbilical cord blood transplantation (UCBT) using low-dose anti-thymocyte globulin (ATG) in children diagnosed with severe aplastic anemia (SAA). METHODS: This retrospective case series study was conducted involving pediatric SAA patients treated at the Capital Institute of Pediatrics from January 2020 to February 2023. All patients underwent a reduced-intensity conditioning (RIC) regimen alongside low-dose ATG. RESULTS: The study comprised nine patients (five males) with a median age of 5 years (range: 1.7 to 7 years). The median follow-up duration was 799 days (range: 367 to 1481 days), during which all patients survived. The median time interval from diagnosis to transplantation was 3 months (range: 1 to 9 months). The median dosage of ATG administered was 5 mg/kg (range: 2.5 to 7.5 mg/kg). The median durations for granulocyte and platelet engraftment were 15 days (range: 12 to 23 days) and 26 days (range: 12 to 41 days), respectively. Three patients experienced grade 2-4 acute graft-versus-host disease (aGVHD). Epstein-Barr virus (EBV) reactivation was observed in three patients, while cytomegalovirus (CMV) reactivation occurred in seven patients, with no cases of CMV disease or post-transplant lymphoproliferative disorder (PTLD). One patient experienced recurrence 15 months after transplantation due to influenza A infection. CONCLUSION: These findings indicate that SAA patients may attain a favorable prognosis following UCBT with a RIC regimen combined with low-dose ATG.

[Analysis of efficacy and prognosis of allogeneic hematopoietic stem cell transplantation for the treatment of combined immunodeficiency].

Objective: To evaluate the efficacy of allogeneic hematopoietic stem cell transplantation for the treatment of combined immunodeficiency (CID) and explore prognostic risk factors. Methods: In this retrospective cohort study, clinical characteristics, laboratory tests and prognosis of 73 CID children who underwent allogeneic hematopoietic stem cell transplantation from February 2014 to April 2022 in the Children's Hospital of Fudan University were analyzed. Based on the subtypes of diseases, all patients were divided into severe combined immunodeficiency disease (SCID) group and other CID group. Based on the types of donors, all patients were divided into matched sibling donor group, matched unrelated donor group, unrelated cord blood group, and haploidentical donor group. Kaplan-Meier method and Log-Rank test were used to analyze the survival data. Cox regression was used to analyze prognostic factors. Results: Among the 73 patients, there were 61 (84%) males and 12 (16%) females. Fifty-five (75%) patients were SCID, and 18 (25%) patients were other CID. Donor source included 2 (3%) matched sibling donors (MSD), 3 (4%) matched unrelated donors (MUD), 64 (88%) unrelated cord blood (UCB), and 4 (5%) haploidentical donors. The age at transplant was 10.7 (5.9, 27.5) months, and the follow-up time was 36.2 (2.5, 62.9) months. The 3-year overall survival rate of 73 patients with CID was (67±6) %. No significant difference was found in the 3-year overall survival rates between patients with SCID (55 cases) and other CID (18 cases) ((64±7) % vs. (78±10) %, χ2=1.31, P=0.252). And no significant difference was found in the 3-year overall survival rates among patients who received MSD or MUD (5 cases), UCB (64 cases), and haploidentical donor (4 cases) transplant (100% vs. (66±6)% vs. (50±25) %, χ2=2.30, P=0.317). Cox regression analysis showed that the medical history of sepsis (HR=2.55, 95%CI 1.05-6.20, P=0.039) and hypoalbuminemia at transplant (HR=2.96, 95%CI 1.14-7.68, P=0.026) were independent risk factors for the prognosis of allogeneic hematopoietic stem cell transplantation in pediatric patients with CID. Conclusions: Allogeneic hematopoietic stem cell transplantation is an effective treatment for CID. The medical history of sepsis and hypoalbuminemia at transplant were risk factors for prognosis. Enhancing infection prevention and nutritional intervention before transplant can improve patient prognosis.

Increased donor inhibitory KIR are associated with reduced GVHD and improved survival following HLA-matched unrelated donor HCT in paediatric acute leukaemia.

Killer immunoglobulin-like receptor (KIR) and KIR-ligand (KIRL) interactions play an important role in natural killer cell-mediated effects after haematopoietic stem cell transplantation (HCT). Previous work has shown that accounting for known KIR-KIRL interactions may identify donors with optimal NK cell-mediated alloreactivity in the adult transplant setting. Paediatric acute leukaemia patients were retrospectively analysed, and KIR-KIRL combinations and maximal inhibitory KIR ligand (IM-KIR) scores were determined. Clinical outcomes were examined using a series of graphs depicting clinical events and endpoints. The graph methodology demonstrated that prognostic variables significant in the occurrence of specific clinical endpoints remained significant for relevant downstream events. KIR-KIRL combinations were significantly predictive for reduced grade 3-4 aGVHD likelihood, in patients transplanted with increased inhibitory KIR gene content and IM-KIR = 5 scores. Improvements were also observed in associated outcomes for both ALL and AML patients, including relapse-free survival, GRFS and overall survival. This study demonstrates that NK cell KIR HLA interactions may be relevant to the paediatric acute leukaemia transplant setting. Reduction in aGVHD suggests KIR effects may extend beyond NK cells. Moving forward clinical trials utilizing donors with a higher iKIR should be considered for URD HCT in paediatric recipients with acute leukaemia to optimize clinical outcomes.

Combined effect of unrelated donor age and HLA peptide-binding motif match status on HCT outcomes.

ABSTRACT: An HLA-mismatched unrelated donor who is class I peptide-binding motif (PBM)-matched is preferred over a PBM-mismatched donor. We hypothesized that using a younger donor (aged ≤35 years vs >35 years) could compensate for the inferior overall survival (OS) associated with PBM mismatches. We compared 6 groups: HLA-matched/younger donor (n = 10 531), HLA-matched/older donor (n = 3572), PBM-matched/younger donor (n = 357), PBM-matched/older donor (n = 257), PBM-mismatched/younger donor (n = 616), and PBM-mismatched/older donor (n = 339) in patients undergoing transplantation with conventional graft-versus-host disease prophylaxis. In multivariate analysis, HLA-matched/younger donors were associated with superior OS relative to any other group. Pairwise comparisons showed that donor age significantly impacted OS in both HLA-matched and HLA-mismatched groups. Moreover, younger donors appeared to negate the detrimental effect of PBM mismatching: the PBM-matched/younger donor group had similar OS as the HLA-matched/older donor group and the PBM-mismatched/younger donor group had similar OS as the PBM-matched/older donor group. Our study suggests that older unrelated donor age and PBM mismatching confer similarly adverse effects on OS and the impacts are additive, a finding which may widen the "acceptable" donor pool. The best OS is observed with HLA-matched/younger donors and the worst with PBM-mismatched/older donors. These findings should be validated with other data sets and with posttransplantation cyclophosphamide-based prophylaxis.

PTCy versus ATG as graft-versus-host disease prophylaxis in mismatched unrelated stem cell transplantation.

There is an increased risk of GVHD and of non-relapse mortality (NRM) after allogeneic stem cell transplantations (alloSCT) when mismatched unrelated donors (MMUD) are used. In Europe, it is standard practice to use rabbit anti-thymocyte globulin (rATG) to reduce the high NRM and GVHD risks after MMUD alloSCT. As an alternative to rATG, post-transplantation Cyclophosphamide (PTCy) is in increasing clinical use. It is currently impossible to give general recommendations regarding preference for one method over another since comparative evidence from larger data sets is lacking. To improve the evidence base, we analyzed the outcome of rATG vs. PTCy prophylaxis in adult patients with hematologic malignancies undergoing first peripheral blood alloSCT from MMUD (9/10 antigen match) between Jan 2018 and June 2021 in the database of the European Society for Blood and Marrow Transplantation (EBMT). We performed multivariate analyses using the Cox proportional-hazards regression model. We included 2123 patients in the final analyses (PTCy, n = 583; rATG, n = 1540). p values and hazard ratios (HR) presented here are multivariate outcomes. Two years after alloSCT we found a lower NRM in the PTCy group of 18% vs. 24.9% in the rATG group; p = 0.028, HR 0.74. Overall survival in the PTCy cohort was higher with 65.7% vs. 55.7% in the rATG cohort; p < 0.001, HR 0.77. Progression-free survival was also better in the PTCy patients with 59.1% vs. 48.8% when using rATG; p = 0.001, 0.78. The incidences of chronic GVHD and acute GVHD were not significantly different between the groups. We found significantly lower NRM as well as higher survival in recipients of peripheral blood alloSCTs from MMUD receiving PTCy as compared to rATG. The results of the current analysis suggest an added value of PTCy as GVHD prophylaxis in MMUD alloSCT.

ATG or post-transplant cyclophosphamide to prevent GVHD in matched unrelated stem cell transplantation?

There is a high risk of GVHD and non-relapse mortality (NRM) after allogeneic stem cell transplantations (alloSCT) from unrelated donors. Prophylaxis with rabbit anti-thymocyte globulin (rATG) is standard in Europe but post-transplantation Cyclophosphamide (PTCy) is an emerging alternative. We analyzed outcomes of rATG (n = 7725) vs. PTCy (n = 1039) prophylaxis in adult patients with hematologic malignancies undergoing peripheral blood alloSCT from 10/10 antigen-matched unrelated donors (MUD) between January 2018 and June 2021 in the EBMT database. The provided P-values and hazard ratios (HR) are derived from multivariate analysis. Two years after alloSCT, NRM in the PTCy group was 12.1% vs. 16.4% in the rATG group; p = 0.016; HR 0.72. Relapse was less frequent after PTCy vs. rATG (22.8% vs. 26.6%; p = 0.046; HR 0.87). Overall survival after PTCy was higher (73.1% vs. 65.9%; p = 0.001, HR 0.82). Progression free survival was better after PTCy vs. rATG (64.9% vs. 57.2%; p < 0.001, HR 0.83). The incidence of chronic GVHD was lower after PTCy (28.4% vs. rATG 31.4%; p = 0.012; HR 0.77), whereas the incidence and severity of acute GVHD were not significantly different. GVHD-free relapse-free survival was significantly higher in the PTCy arm compared to the rATG arm (2 y incidence: 51% vs. 45%; HR: 0.86 [95% CI 0.75-0.99], p = 0.035). In the absence of evidence from randomized controlled trials, our findings support a preference for the use of PTCy in adult recipients of peripheral blood alloSCTs from MUD.

[Risk prediction and function evaluation by T-cell epitope model and expression model of HLA-DPB1 mismatching in unrelated-donor hematopoietic stem cell transplantations].

Objective: To evaluate the risk prediction and assessment function of HLA-DPB1 T-cell epitope (TCE) model and expression model in human leukocyte antigen (HLA)-matched unrelated hematopoietic stem cell transplantation (MUD-HSCT) with HLA-DPB1 mismatching. Methods: A total of 364 (182 pairs) potential MUD-HSCT donors and recipients confirmed by HLA high-resolution typing in Shaanxi Blood Center from 2016 to 2019 were analyzed retrospectively. Of the 182 recipients, there were 121 males and 61 females with an average age of (26.3±14.2) years. Of the 182 donors, there were 148 males and 34 females with an average age of (33.7±7.5) years. Polymerase chain reaction-sequence-based typing (PCR-SBT), next-generation sequencing (NGS) and polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSO) based on LABScan®3D platform were used for high-resolution typing of HLA-A, B, C, DRB1, DQB1, DPB1 gene, and PCR-SBT was used for single nucleotide polymorphism (SNP) typing. TCE model and expression model were used to predict and evaluate the HLA-DPB1 mismatch pattern and acute graft-versus-host-disease (aGVHD) risk. Results: A total of 26 HLA-DPB1 alleles and their 3'-UTR rs9277534 SNP genotypes were detected in this study population, and two new alleles HLA-DPB1*1052∶01 and HLA-DPB1*1119∶01 were found and officially named. The overall mismatch rate of HLA-DPB1 in MUD-HSCT donors and recipients was 90.66% (165/182). In TCE model, the HLA-DPB1 mismatch rates of permissible mismatch (PM) and non-permissible mismatch (non-PM) were 47.80% (87/182) and 42.86% (78/182), respectively. The non-PM in GvH direction was 13.73% (25/182), and which in HvG direction was 29.12% (53/182). A total of 73 pairs of donors and recipients in TCE model met the evaluation criteria of expression model. Among of TCE PM group, recipient DP5 mismatches accounted for 34.25% (25/73) were predicted as aGVHD high risk according to expression model. For the TCE non-PM group, both the recipient DP2 mismatches of 6.85% (5/73) and recipient DP5 mismatches of 10.86% (8/73) were predicted to be at high risk for aGVHD. Risk prediction by TCE model and expression model was 27.27% concordant and 16.97% unconcordant. Conclusions: TCE model and expression model are effective tools to predict aGVHD risk of MUD-HSCT. Comprehensive application of the two models is helpful to the hierarchical assessment of HSCT risk.

Providing hematopoietic stem cell products from unrelated donors to the world: DKMS donor centers and DKMS Registry.

Allogeneic hematopoietic stem cell (HSC) transplantation is a curative therapy for many severe blood diseases. As many patients have no suitable family donor, large unrelated donor registries and donor centers have been established in many countries, along with an international system for the provision of unrelated donor HSC products. As an essential part of this system, DKMS operates donor centers in 7 countries with a total of 12.2 million donors and over 114,000 donations so far, and a multinational donor registry. In 2022, DKMS donors contributed 57.5% of all cross-border donations worldwide. In this review, we describe the international system for the provision of unrelated donor HSC products as well as tasks and responsibilities of donor registries and donor centers. We also discuss relevant aspects of DKMS donor centers, namely donor file composition, matching and donation probabilities and actual donations, and the unique multinational approach of the DKMS Registry.

Risk factors for graft-versus-host-disease after donor lymphocyte infusion following T-cell depleted allogeneic stem cell transplantation.

Introduction: Unmodified donor lymphocyte infusions (DLI) after allogeneic stem cell transplantation (alloSCT) can boost the beneficial Graft-versus-Leukemia (GvL) effect but may also induce severe Graft-versus-Host-Disease (GvHD). To improve the balance between GvL and GvHD, it is crucial to identify factors that influence the alloreactivity of DLI. Methods: We investigated the effects of the presence of patient-derived antigen-presenting cells at time of DLI as estimated by the bone marrow (BM) chimerism status, lymphopenia as measured by the absolute lymphocyte count (ALC) at time of DLI, and the presence of a viral infection (de novo or reactivation) close to DLI on the risk of GvHD after DLI. The cohort consisted of patients with acute leukemia or myelodysplastic syndrome who prophylactically or pre-emptively received DLI as standard care after alemtuzumab-based alloSCT. In patients at high risk for relapse, DLI was administered at 3 months after alloSCT (n=88) with a dose of 0.3x106 or 0.15x106 T cells/kg in case of a related or unrelated donor, respectively. All other patients (n=76) received 3x106 or 1.5x106 T cells/kg, respectively, at 6 months after alloSCT. Results: For both DLIs, patients with reduced-intensity conditioning and an unrelated donor had the highest risk of GvHD. For DLI given at three months, viral infection within 1 week before and 2 weeks after DLI was an additional significant risk factor (hazard ratio (HR) 3.66 compared to no viral infection) for GvHD. At six months after alloSCT, viral infections were rare and not associated with GvHD. In contrast, mixed BM chimerism (HR 3.63 for ≥5% mixed chimerism compared to full donor) was an important risk factor for GvHD after DLI given at six months after alloSCT. ALC of <1000x106/l showed a trend for association with GvHD after this DLI (HR 2.05 compared to ≥1000x106/l, 95% confidence interval 0.94-4.45). Furthermore, the data suggested that the presence of a viral infection close to the DLI at three months or ≥5% mixed chimerism at time of the DLI at six months correlated with the severity of GvHD, thereby increasing their negative impact on the current GvHD-relapse-free survival. Conclusion: These data demonstrate that the risk factors for GvHD after DLI depend on the setting of the DLI.

Effect of allogeneic hematopoietic stem cell transplantation for chronic granulomatous disease in children: A multicentre, retrospective cohort study in China.

Chronic granulomatous disease (CGD) in children is a rare primary immunodeficiency disorder that can lead to life-threatening infections and inflammatory complications. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is increasingly being used to treat severe CGD in children. We conducted a multicenter retrospective analysis of children with CGD who were treated with allo-HSCT at four pediatric hematopoietic stem cell transplant centers in China from September 2005 to December 2019. The study included a total of 171 patients (169 males and 2 females). The median age at the time of transplantation was 6.1 (0-16.4) years. Among them, 154 patients had X-linked recessive inheritance caused by CYBB gene mutations, 12 patients were autosomal recessive, 1 patient had DNAH11 and HYDIN gene mutations, and 4 patients had no gene mutations. The median follow-up period was 36.3 (1.9-79) months. All participating patients were applied to myeloablative conditioning (MAC) regimens. The rates of OS, EFS, and GEFS within three years were 87.5%, 85.3%, and 75.2%, respectively. The total graft failure and the total mortality rate were 5.3% and 11.1%. The cumulative incidence of acute GVHD was 53.8% and the incidence of chronic GVHD was 12.9%, The incidence of chronic GVHD was higher for patients who received unrelated donor cord blood stem cell transplantation (UD-CB) (P = 0.001). Chronic GVHD and coinfections are the risk factors for OS and EFS in patients with CGD after receiving allo-HSCT. UD-CB is a risk factor for EFS and the presence of pneumonia before transplantation is a risk factor for OS. In conclusion, through this study, we have demonstrated that allo-HSCT has excellent efficacy in the treatment of CGD in children, especially, RD-haplo is associated with a lower rate of graft failure incidence and mortality than the treatment modalities of other donor type. Therefore, allo-HSCT is strongly recommended when a well-matched donor is available. If a well-matched donor is not available, the HLA-mismatched donor should be carefully evaluated, and the conditioning regimen modified accordingly.

Cytomegalovirus Reactivations in Allogeneic Hematopoietic Stem Cell Transplantation from HLA-Matched and Haploidentical Donors with Post-Transplantation Cyclophosphamide.

Cytomegalovirus (CMV) reactivations cause significant morbidity in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. Graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide (PTCy) is associated with an increased risk of CMV infections. Data are limited comparing HSCT with PTCy performed from matched sibling donors (MSDs), matched unrelated donors (MUDs), and haploidentical (Haplo) donors. In the present study, we aimed to characterize CMV reactivation and recurrence in patients with hematologic malignancies undergoing HSCT from MSD, MUD, and Haplo donors using PTCy as GVHD prophylaxis in the pre-letermovir era. We also analyzed risk factors of CMV reactivation, including GVHD as a time-dependent variable, on the incidence and mortality associated with CMV infections. We analyzed CMV reactivation in patients undergoing HSCT from 160 MSDs, 124 MUDs, and 82 Haplo donors from a single institution. Uniform GVHD prophylaxis with PTCy, sirolimus, and mycophenolate mofetil was given irrespective of donor type. Overall, 46% of patients had at least 1 CMV reactivation. The 1-year cumulative incidence of CMV infection was 39% for MSD, 44% for MUD, and 62% for Haplo donors (P < .001), with 96% of reactivations occurring before day +100. Multivariate analysis identified factors associated with the first CMV reactivation, including Haplo donor, positive recipient CMV serology, older patient age, and grade II-IV acute GVHD. The 1-year cumulative incidence of second reactivation from HSCT was 13%. Recipient CMV seropositivity, older patient age, and grade II-IV acute GVHD, but not type of donor, were identified as adverse factors for second CMV reactivation in multivariate analysis. The 1-year cumulative incidence of a third reactivation post HSCT was 4.4%. Ten cases of CMV disease were recorded, with no attributable deaths. Nevertheless, the risk for nonrelapse mortality was greater for patients who experienced CMV reactivation in multivariate time-dependent Cox model analysis. CMV reactivation is frequent in HSCT with PTCy in patients not receiving letermovir prophylaxis. Identified risk factors include the use of a Haplo donor, recipient CMV seropositivity, and grade II-IV acute GVHD. The prevalence of recurrent CMV reactivations is a noteworthy issue, especially after acute GVHD, warranting trials of secondary prophylaxis strategies.

Factors Associated with Opting Out of an Unrelated Hematopoietic Stem Cell Donor Registry: Differences and Similarities across Five Key Groups of Young Race/Ethnically Diverse Potential Donors in the United States.

Young adults from underserved racial/ethnic groups are critically needed as unrelated hematopoietic stem cell (HSC) donors, yet they are more likely than other groups to opt out of donation after having matched a patient. Understanding which factors are most strongly associated with opting out among young underserved racial/ ethnic registered donors compared with their White counterparts will provide the basis for specific interventions to improve donor retention. We sought to determine the key, modifiable psychosocial, registry-related, and donation-related characteristics that are uniquely associated with opting out across 5 key racial/ethnic groups of young HSC donor registry members who had been contacted as a potential match for a patient. This study examines data from a large cross-sectional survey of young (age 18 to 30) registry members shortly after they preliminarily matched a patient (CT-stage) and continued toward or opted out of donation (CT-C and CT-NI), stratified by racial/ethnic group and sex. We assessed psychosocial, registry-related, and donation-related characteristics for all participants. We used chi-squared and F tests to assess differences between racial/ethnic groups. A separate logistic regression analysis for each racial/ethnic group was conducted to quantify adjusted associations between each variable and opting out. Then, we compared these associations across the racial/ethnic groups by evaluating the interaction effect between each variable and racial/ethnic group, with the same outcome (CT-C versus CT-NI) in question. Nine hundred thirty-five participants were surveyed, including 284 White, 165 Hispanic, 191 Black, 192 Asian/Pacific Islander, and 103 Multiracial/multiethnic participants. There were significant differences across racial/ethnic groups in values/goals, religious objections to donation, HSC-related medical mistrust, and parental involvement in donation decisions. Adjusted logistic regression subgroup analyses indicated that ambivalence was strongly associated with opting out across all racial/ethnic groups. Greater focus on intrinsic life goals (e.g., raising a family, becoming a community leader, influencing social values) was associated with opting out in the Multiracial/multiethnic, Hispanic, and Asian/Pacific Islander groups. Healthcare mistrust and insufficient registry contact was a significant factor for Hispanic participants. Protective factors against opting out included remembering joining the registry (Black participants), and parental support for donation decision (Asian/Pacific Islander participants). The performance of each logistic regression model was strong, with area-under-the curve ≥.88, CT-stage outcome classification accuracy ≥89%, and good fit between expected and observed opt-out probabilities. In the analysis across different racial/ethnic groups, the only significant interaction was race/ethnicity by whether more contact with the registry would have changed the decision at CT-stage; this variable was significant only for the Hispanic group. In the within-group analysis for Hispanic participants, the "more registry contact" variable was strongly associated with opting out (odds ratio 5.8, P = .03). Consistent with a growing body of HSC donor research, ambivalence was a key factor associated with opting-out for all racial/ethnic groups. Other key variables were differentially associated with opting-out depending on racial/ethnic group. Our study highlights key variables that registries should focus on as they develop targeted and tailored strategies to enhance commitment and reduce attrition of potential donors.

Improving Unrelated Donor Equity: Assessing Mismatched Donor Opportunities with Real-World Data in a Minority-Predominant Cohort.

Recent advances in graft-versus-host disease (GVHD) prophylaxis including post-transplant cyclophosphamide (PTCy) and abatacept have significantly improved outcomes following HLA-mismatched allogenic hematopoietic stem cell transplantation (allo-HSCT) and have tremendous potential for reducing racial disparities in donor availability. A recent small study employing bone marrow as the source of stem cells showed similar outcomes after 5/8 versus 7/8 matches and is currently being tested in a larger study using peripheral blood stem cells. In this study, we examine real-world alternative donor HSCT options for a minority-predominant cohort in the Bronx, NY, focusing on the availability of lesser-matched (5/8 to 7/8) donors. Records of patients who underwent HLA typing at Montefiore Medical Center (2019 to 2022) were reviewed. The National Marrow Donor Program registry was queried to evaluate the availability of donors with at least 99% likelihood of HLA match at various levels (5/8, 6/8, 7/8, 8/8). Two hundred forty-one patients were included, 70% were non-White. Although the availability of ≥7/8 donors was less common in non-White patients, 100% of patients from each group had at least one or more 5/8 and 6/8 HLA-matched donors and more than 80% of these patients had >100 potential 5/8 and 6/8 HLA-matched donors. There was no statistical difference by race or ethnicity in the mean number of donors at 5/8 and 6/8 HLA-match levels. We demonstrate through real-world data that patients from diverse ethnic and racial backgrounds have access to 5/8 and 6/8 HLA-matched donors for allo-HSCT, potentially eliminating disparities in donor availability and allowing prioritization of other donor selection characteristics such as donor age, sex, ABO, and B leader matching. Further work is needed to study whether the use of mismatched donors offers a more potent graft-versus malignancy effect and optimal GVHD prophylaxis.

Hematopoietic stem cell transplantation in children with chronic granulomatous disease: the Spanish experience.

Introduction: Hematopoietic stem cell transplantation (HCT) can cure chronic granulomatous disease (CGD). However, transplant-associated morbidity or mortality may occur, and it is still controversial which patients benefit from this procedure. The aim of this retrospective study was to evaluate the outcome of pediatric patients who received HCT in one of the Spanish pediatric transplant units. Results: Thirty children with a median age of 6.9 years (range 0.6-12.7) were evaluated: 8 patients received a transplant from a sibling donor (MSD), 21 received a transplant from an unrelated donor (UD), and 1 received a haploidentical transplant. The majority of the patients received reduced-intensity conditioning regimens based on either busulfan plus fludarabine or treosulfan. Relevant post-HCT complications were as follows: i) graft failure (GF), with a global incidence of 28.26% (CI: 15.15-48.88), 11.1% in patients with MSD (1.64-56.70) and 37.08% in unrelated donors (19.33-63.17); and ii) chronic graft-versus-host disease (GVHD), with an incidence of 20.5% (8.9-43.2), 11.1% in patients with MSD (1.64-56.70) and 26.7% in unrelated donors (10.42-58.44). Post-HCT infections were usually manageable, but two episodes of pulmonary aspergillosis were diagnosed in the context of graft rejection. The 2-year OS was 77.3% (55.92-89.23). There were no statistically significant differences among donor types. Discussion: HCT in patients with CGD is a complex procedure with significant morbidity and mortality, especially in patients who receive grafts from unrelated donors. These factors need to be considered in the decision-making process and when discussing conditioning and GVHD prophylaxis.

Long-term lymphocyte subset number reconstitution is unique but comparable between umbilical cord blood and unrelated bone marrow transplantation.

The number of umbilical cord blood transplantation (U-CBT) procedures has been growing annually, but little research has been done on long-term immune recovery after U-CBT. Infection risk is high in U-CBT recipients, and this can be partially attributed to immature immunocompetent cells in umbilical cord blood. In this study, we analyzed lymphocyte subset (LST) number to determine the long-term recovery timeline. We included 36 U-CBT and 10 unrelated bone marrow transplantation (U-BMT) recipients who survived more than 2 years after transplantation, and followed them for up to 10 years post-transplant. Recovery kinetics in the early phase post-transplant was different for each LST. Recovery of CD19+ B cells was faster after U-CBT than after U-BMT in the first 5 years after transplantation. Although CD4+ T cells increased in the first several months after U-CBT, long-term cell count recovery was impaired in approximately 20% of patients. Thus, although the LST recovery pattern after U-CBT was unique, LST number recovery was statistically comparable between U-CBT and U-BMT past 5 years post-transplantation.