Haploidentical versus Cord Blood transplantation in pediatric AML. A retrospective outcome analysis on behalf of the pediatric subcommittee of GETH (Grupo Español de Trasplante Hematopoyético).

Haploidentical stem cell transplantation (Haplo-SCT) and cord blood transplantation (CBT) are both effective alternative treatments in patients suffering from Acute Myeloid Leukemia (AML) and lacking a matched HLA donor. In the last years, many centers have abandoned CBT procedure mostly due to concern about poorer immune recovery compared to Haplo-SCT. We conducted a retrospective multicenter study comparing the outcomes using both alternative approaches in AML. A total of 122 transplants (86 Haplo-SCT and 36 CBT) from 12 Spanish centers were collected from 2007 to 2021. Median age at Hematopoietic stem cell transplantation (HSCT) was 7 years (0.4-20). Thirty-nine patients (31.9%) showed positive minimal residual disease (MRD) at HSCT and a previous HSCT was performed in 37 patients (30.3%). The median infused cellularity was 14.4 × 10^6/kg CD34+ cells (6-22.07) for haplo-SCT and 4.74 × 10^5/Kg CD34+ cells (0.8-9.4) for CBT. Median time to neutrophil engraftment was 14 days (7-44) for Haplo-SCT and 17 days (8-29) for CBT (p=0.03). The median time to platelet engraftment was 14 days (6-70) for Haplo-SCT and 43 days (10-151) for CBT (p<0.001). Graft rejection was observed in 13 Haplo-SCT (15%) and in 6 CBT (16%). The cumulative incidence of acute GvHD grade II-IV was 54% and 51% for Haplo-SCT and CBT respectively (p=0.5). The cumulative incidence of severe acute GvHD (grade III-IV) was 22% for Haplo-SCT and 25% for CBT (p= 0.9). There was a tendency to a higher risk of chronic GvHD in the Haplo-SCT group being the cumulative incidence of 30% for Haplo-SCT and 12 % for CBT (p= 0.09). The cumulative incidence of relapse was 28% and 20% for Haplo-SCT and CBT respectively (p= 0.6). We did not observe statistically significant differences in outcome measures between Haplo-SCT and CBT procedures: 5-year overall survival (OS) 64% vs 57% (p=0.5), 5-year disease-free survival (DFS) 58% vs 57% (p=0.8), GvHD-free and relapse-free survival (GFRFS) 41% vs 54% (p=0.3), and cumulative incidence of transplant-related mortality (TRM) 14% vs 15% (p=0.8), respectively. In the multivariate analysis MRD positivity and a disease status >CR1 at the time of HSCT were significantly associated with poorer outcomes (p<0.05). In conclusion, our study supports that both haploidentical and cord blood transplantation show comparable outcomes in pediatric AML patients. We obtained comparable survival rates, although CBT showed a trend to lower rates of chronic GvHD and higher GFRFS, demonstrating that it should still be considered a valuable option, particularly for pediatric patients.

Impact of payment source, referral site, and place of residence on outcomes after allogeneic transplantation in Mexico.

BACKGROUND: The impact of social determinants of health in allogeneic transplant recipients in low- and middle-income countries is poorly described. This observational study analyzes the impact of place of residence, referring institution, and transplant cost coverage (out-of-pocket vs government-funded vs private insurance) on outcomes after allogeneic hematopoietic stem cell transplantation (alloHSCT) in two of Mexico's largest public and private institutions. AIM: To evaluate the impact of social determinants of health and their relationship with outcomes among allogeneic transplant recipients in Mexico. METHODS: In this retrospective cohort study, we included adolescents and adults ≥ 16 years who received a matched sibling or haploidentical transplant from 2015-2022. Participants were selected without regard to their diagnosis and were sourced from both a private clinic and a public University Hospital in Mexico. Three payment groups were compared: Out-of-pocket (OOP), private insurance, and a federal Universal healthcare program "Seguro Popular". Outcomes were compared between referred and institution-diagnosed patients, and between residents of Nuevo Leon and out-of-state. Primary outcomes included overall survival (OS), categorized by residence, referral, and payment source. Secondary outcomes encompassed early mortality, event-free-survival, graft-versus-host-relapse-free survival, and non-relapse-mortality (NRM). Statistical analyses employed appropriate tests, Kaplan-Meier method, and Cox proportional hazard regression modeling. Statistical software included SPSS and R with tidycmprsk library. RESULTS: Our primary outcome was overall survival. We included 287 patients, n = 164 who lived out of state (57.1%), and n = 129 referred from another institution (44.9%). The most frequent payment source was OOP (n = 139, 48.4%), followed by private insurance (n = 75, 26.1%) and universal coverage (n = 73, 25.4%). No differences in OS, event-free-survival, NRM, or graft-versus-host-relapse-free survival were observed for patients diagnosed locally vs in another institution, nor patients who lived in-state vs out-of-state. Patients who covered transplant costs through private insurance had the best outcomes with improved OS (median not reached) and 2-year cumulative incidence of NRM of 14% than patients who covered costs OOP (Median OS and 2-year NRM of 32%) or through a universal healthcare program active during the study period (OS and 2-year NRM of 19%) (P = 0.024 and P = 0.002, respectively). In a multivariate analysis, payment source and disease risk index were the only factors associated with overall survival. CONCLUSION: In this Latin-American multicenter study, the site of residence or referral for alloHSCT did not impact outcomes. However, access to healthcare coverage for alloHSCT was associated with improved OS and reduced NRM.

[Current trends in the treatment of aplastic anemia].

Aplastic anemia is a syndrome characterized by reduced hematopoietic stem cells, bone marrow hypoplasia, and pancytopenia, and is often considered a T-cell-mediated autoimmune disease. It is predominantly treated with hematopoietic stem cell transplantation and immunosuppressive therapy with anti-human thymocyte immunoglobulin (ATG) and cyclosporine. Only rabbit ATG was previously available in Japan, but equine ATG was recently approved for use in 2023. Thrombopoietin receptor agonists available in Japan are oral eltrombopag and injectable romiplostim. In hematopoietic stem cell transplantation for aplastic anemia, a conditioning regimen of reduced-dose cyclophosphamide and fludarabine has been used to reduce cardiotoxicity. Human leukocyte antigen haploidentical stem cell transplants have also been developed, and their use in patients without a donor is increasingly reported. Future advancements in novel drugs and transplantation therapies could revolutionize the management of aplastic anemia.

Haplo-cord transplant. Realizing the potential of umbilical cord blood grafts. - A review of techniques and analysis of outcomes.

The combination of cord blood transplant with progenitor cells from partially HLA-matched adult donors (haplo-cord transplant) has been used over the past two decades. In Europe and the US the adult donor graft is CD34 selected and provides early hematopoiesis, but durable engraftment derives from the cord blood graft (CD34 selected haplo-cord). Neutrophil recovery is prompt and rates of acute and chronic GVHD are low. Recent Chinese studies combine cord blood grafts with T-replete haplo-identical grafts (unmodified haplo-cord). The haplo graft usually establishes dominance and UCB chimerism is rarely detected. Comparison studies suggest considerably decreased rates of relapse and improved outcomes, compared with either haplo-identical transplant or CBU transplant, particularly in patients with advanced leukemia. A recent prospective randomized study confirms this. Haplo-cord mitigates the engraftment delay of UCB transplant. The unique biology of UCB grafts results in low GVHD and improved GVL especially beneficial in high-risk disease.

Improving Outcomes with Haploidentical Stem Cell Transplantation [HaploSCT] in Children Using Post-transplant Cyclophosphamide: a Single Center Experience.

Haplo-identical stem cell transplant using post-transplant cyclophosphamide is increasingly being used in children without a matched sibling donor. Between 2010 and June 2021, 127 children underwent 138 transplants with a median age of 7.1 years for malignant and non-malignant disorders. Conditioning regimens included both myeloablative and reduced intensity regimens with peripheral blood stem cells as the main graft source. Engraftment occurred in 113 [81.9%] at a median of 16 days [range: 10-32] with primary graft failure in 10.2%. Cumulative incidence of grade II-IV acute graft versus host disease (GVHD) was 49.5% and chronic GVHD in 40.7%. Majority [92.7%] had at least one infection with 31% incidence of bacterial infection, 76% incidence of viral and 16% incidence of fungal infection. The 2-year overall survival (OS) is 54.9 ± 4.6% with a lower survival among young children aged 0-5 years [28.2 ± 6.4%] compared to 5-10 years [71.3 ± 6.8%] and 11-15 years [55.7 ± 8.8%] [p = 0.032]. 2-year OS has gradually improved from 25.0 ± 2.1% for 2010-2013 to 47.5 ± 6.2% for 2014-2017 and 67.1 ± 6.6% for 2018-2021 [p = 0.049]. On multivariate analysis, bacterial infection [p = 0.017], invasive fungal disease [p = 0.002] and graft failure [p = 0.029] negatively impacted overall survival. Haplo-identical SCT with post-transplant cyclophosphamide is a reasonable option for children who do not have a matched sibling donor. Strategies to reduce graft failure, infection related mortality and GVHD needs to be explored.

Daratumumab for De-sensitization of Donor Specific Antibodies: Is it a Quicker and Easier way?

Antibodies directed against donor-specific HLA loci (DSA) has been proved as a main culprit for graft rejection, more specifically in HLA mismatched and haplo-identical transplant settings. There is no standardized regimen to manage the presence of DSAs in allogeneic stem cell transplantations (allo-SCTs). Most widely regimen includes combination of rituximab (anti CD20 antibody), Immunoglobulin (IVIG), plasma exchange, and buffy coat infusion, which is costly and time-consuming. Daratumumab (anti CD38 monoclonal antibody) is an effective therapeutic agent to deplete plasma cells and hence, it has a potential to reduce DSA. It has been utilized widely in solid organ transplantation for this purpose. We used this agent in two haplo-identical transplant patients to eliminate or reduce DSA. We observed definite either reduction or elimination in DSA levels in these cases and we could perform haplo-identical transplantation without much delay and with successful primary engraftment in both scenarios. We emphasize that literature on real-world utilization of daratumumab in allo-SCTs is limited. However, it has been utilized widely in solid organ transplantation for this purpose. Our experience with daratumumab regarding effective reduction of DSA followed by successful engraftment might encourage its use in de-sensitization protocols without much delay in transplantation.

211At-Labeled Anti-CD45 Antibody as a Nonmyeloablative Conditioning for Canine DLA-Haploidentical Stem Cell Transplantation.

The α-emitter 211At deposits a high amount of energy within a few cell diameters, resulting in irreparable DNA double-strand breaks while minimizing off-target toxicity. We investigated the use of the 211At-labeled anti-CD45 monoclonal antibody (mAb) 211At-CD45-B10 as a nonmyeloablative conditioning regimen for dog-leukocyte-antigen-haploidentical hematopoietic cell transplantation. Methods: Seventeen healthy dogs were injected with either a 0.50 (n = 14) or 0.75 (n = 3) mg/kg dose of anti-CD45 mAb labeled with 211At (8.436-23.199 MBq [0.228-0.627 mCi/kg]) on day -3. Peripheral blood stem cells from dog-leukocyte-antigen-haploidentical donors were given on day 0. Peripheral blood chimerism was calculated by polymerase chain reaction assays, and blood clearance of the radioimmunoconjugate was studied using enzyme-linked immunosorbent assay and radioactivity measurements of serial blood samples. Results: All dogs achieved donor chimerism by day 28 (range, 27%-100%). The hematopoietic engraftment rate was 100%, though engraftment durability was variable. No difference in absorbed dose to blood was seen for the 2 mAb dosing levels studied. Neutropenia (0-29 cells/µL), lymphocytopenia (36-130 cells/µL), and thrombocytopenia (1.5-9 × 103/µL) with prompt recovery were observed. The main adverse nonhematologic event related to 211At-CD45-B10 was mild reversible transaminitis. Graft-versus-host disease was not seen. Twelve of the 17 dogs survived over 30 d, with donor chimerism ranging from 3% to 99%. Conclusion: The results suggest that nonmyeloablative conditioning with 211At-CD45-B10 could be used in haploidentical hematopoietic cell transplantation though with variable engraftment.

Case report: TP53 c.848G>A germline mutation as a possible screening target at initial diagnosis for acute lymphoblastic leukemia.

BACKGROUD: Li-Fraumeni syndrome is a hereditary tumor syndrome characterized by an elevated risk of malignancy, particularly acute lymphoblastic leukemia (ALL), which can be caused by the heterozygous germline mutation. TP53 gene germline mutation is considered a potential risk factor and crucial prognostic parameter for acute leukemia development and diagnosis, but rarely occurs in adults, and its specific pathogenic significance in acute leukemia is unclear. CASE PRESENTATION: We describes a case of a 45-year-old woman diagnosed with ALL. Whole-exome sequencing approach identified one of the TP53 germline mutations from her bone marrow sample with possible pathogenic significance, c.848G>A (p.Arg283His) heterozygous missense mutation located on exon 8, which was further verified in her hair, oral mucous and nail samples. Family pedigree screening revealed that the same TP53 genetic variant was present in the patient's father and non-donor son, whereas not in the donor. Digital PCR observed that this point mutation frequency dropped post-transplantation but remained low during maintenance therapy when the patient was leukemia-free. CONCLUSION: This suspected Li-Fraumeni syndrome case report with a likely pathogenic heterozygous TP53 variant expands the cancer genetic spectrum. Screening her family members for mutations facilitates identifying the optimal relative donor and avoids unnecessary treatment by monitoring TP53 germline mutations for minimal residual disease following hematopoietic stem cell transplantation. Its potential roles in hematological malignant tumor development and clinical pathogenic implications necessitate further probing.

Haploidentical Versus Mismatched Unrelated Donor Hematopoietic Cell Transplantation: HLA Factors and Donor Age Considerations.

HLA-mismatched unrelated donors and haploidentical related donors are suitable stem cell sources for hematopoietic cell transplantation (HCT) when patients lack HLA-matched donors. Clinical outcome after mismatched HCT is influenced by HLA factors including the similarity of peptide-binding motifs (PBMs) between the patient and unrelated donor, and of the HLA-B leader in unrelated and haploidentical donors. Whether these factors can aid in the selection between mismatched unrelated and haploidentical donors is not known. To address this question, we investigated outcomes between the two donor types defined by matching for the PBM and leader peptide. We compared PBM-matched (n = 614) and mismatched (n = 958) MMUDs with calcineurin-inhibitor-based prophylaxis to four haploidentical groups that received post-transplant cyclophosphamide (PTCy)-based prophylaxis. The haploidentical groups were B-leader matched/DRB1-mismatched (n = 722), B-leader matched/DRB1-matched (n = 154), B-leader mismatched/DRB1-mismatched (n = 493), and B-leader mismatched/DRB1-matched (n = 63). Multivariate analysis showed that the B-leader matched/DRB1-mismatched haploidentical group had the best overall survival (OS) compared to the PBM-matched MMUD, while other haploidentical groups had comparable OS. The PBM-mismatched MMUD showed the poorest outcomes, similar to the B-leader mismatched/DRB1-matched haploidentical group. Among non-HLA factors, donor age was the most significant predictor of OS. These results suggest that a B-leader matched/DRB1 mismatched haploidentical donor might be the preferred choice among donors of similar age. If such a donor is not available, the youngest donor from either PBM-matched unrelated or other haploidentical groups could be a beneficial choice. These findings need validation with both donor groups receiving PTCy-based graft-versus-host disease prophylaxis.

Early Tapering of Cyclosporine Is Feasible in Haploidentical Stem Cell Transplantation: A Single Center Experience.

INTRODUCTION: Cyclosporine-A (CsA) and post transplantation cyclophosphamide (PTCy) are common agents used for graft versus host disease (GVHD) prophylaxis in Haploidentical hematopoietic cell transplantation (haplo-HCT). However, the impact of CsA cessation timing in the posttransplant setting on clinical outcomes is uncertain. We aimed to investigate the impact of a novel approach that integrated early CsA cessation with PTCy utilization. PATIENTS AND METHODS: This study was a single arm retrospective study carried out at a tertiary referral hospital hematology and bone marrow transplantation center between 2009 and 2022. The patients who received haplo-HCT with ATG, PTCy and CsA as GVHD prophylaxis were included. CsA was planned for cessation starting at day 45 to day 60. Acute and chronic GVHD were evaluated and graded. CsA blood concentrations and its impact on acute and chronic GVHD was evaluated. RESULTS: Thirty-one patients composed of 19 (61.3%) male and 12 (38.7%) female patients with a median age of 31 years (20-58). Busulfan and TBI based conditioning regimens were the most utilized regimens. The majority of donors were first degree relatives. Stem cell origin was peripheral blood for all patients. GVHD prophylaxis consisted of ATG, CsA and PTCy. Acute GVHD was observed in 9 (29%) cases, whereas chronic GVHD was seen in 3 (9.7%) cases, with 2 of them having overlapping GVHD. Age, gender, number of chemotherapy lines, transplant characteristics, infused CD34 cell count, and engraftment durations were similar among patients with and without GVHD. Patients with GVHD had similar 1st, 2nd, 3rd and 4th week CsA concentrations compared to patients without GVHD (p > 0.05). The presence of GVHD was not associated with worse progression free survival and overall survival (p = 0.6, p = 0.5, respectively). CMV reactivation was more common in the GVHD group. CONCLUSION: In the current study, we did not find an impact of CsA concentration on GVHD and post-transplant outcomes in Haplo-HCT setting. Therefore, together with the use of PTCy, early CsA cessation can be an option; further studies are needed to understand all aspects of this approach.

Effect of peptide-binding motif on survival of HLA-haploidentical transplantation with post-transplant cyclophosphamide.

Peptide-binding motif (PBM) model, a hierarchical clustering of HLA class I based on their binding specificity, was developed to predict immunopeptidome divergence. The effect of PBM mismatches on outcomes is unknown in HLA-haploidentical haematopoietic cell transplantation with post-transplant cyclophosphamide (PTCy-haplo). We therefore conducted a retrospective study using national registry data in PTCy-haplo. Overall, 1352 patients were included in the study. PBM-A bidirectional mismatch was associated with an increased risk of overall mortality in multivariable analysis (hazard ratio, 1.26; 95% confidence interval, 1.06 to 1.50; p = 0.010). None of relapse, non-relapse mortality (NRM) and graft-versus-host disease showed significant differences according to PBM-A bidirectional mismatch status in the entire cohort. The impact of PBM-A bidirectional mismatch on overall survival (OS) was preserved within the HLA-A genotype bidirectional mismatch population, and their lower OS stemmed from higher relapse rate in this population. The worse OS due to high NRM with PBM-A bidirectional mismatch was prominent in lymphoid malignancies receiving reduced-intensity conditioning. The PBM model may predict outcomes more accurately than HLA genotype mismatches. In conclusion, this study demonstrated that the presence of PBM-A bidirectional mismatch elevated the risk of mortality of PTCy-haplo. Avoiding PBM-A bidirectional mismatch might achieve better outcomes in PTCy-haplo.

Low-dose anti-thymocyte globulin plus low-dose posttransplant cyclophosphamide-based regimen for prevention of graft-versus-host disease in haploidentical peripheral blood stem cell transplantation for pediatric patients with hematologic malignancies.

The low-dose anti-thymocyte globulin (ATG) plus low-dose post transplantation cyclophosphamide (PTCy) -based (low-dose ATG/PTCy-based) regimen had a promising activity in preventing of graft-versus-host disease (GVHD) in adult patients. However, its efficacy in pediatric patients remain to be defined. Here, we presented the findings from 35 pediatric patients undergoing haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) with the new regimen for GVHD prophylaxis. The cumulative incidences (CIs) of grades II-III and III-IV acute GVHD (aGVHD) were 34% (95% CI, 17-48%) and 11% (95% CI, 0-21%) within 180 days post-transplantation, respectively. The CIs of chronic GVHD (cGVHD) and moderate-to-severe cGVHD within 2 years were 26% (95% CI, 7-41%) and 12% (95% CI, 0-25%), respectively. The 2-year probabilities of overall survival, relapse-free survival, and graft-versus-host disease and relapse-free survival were 89% (95% CI, 78-100%), 82% (95% CI, 68-98%) and 59% (95% CI, 43-80%), respectively. The CIs of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivation by day 180 were 37% (95% CI, 19-51%) and 20% (95% CI, 6-32%) respectively. These results strongly advocate for the efficacy of the low-dose ATG/PTCy-based regimen as a robust strategy for GVHD prevention in haplo-PBSCT for pediatric patients.

Clinical characteristics and outcomes of overt gastrointestinal bleeding in children undergoing haploidentical hematopoietic stem cell transplantation: a single-center retrospective analysis.

BACKGROUND: Overt gastrointestinal bleeding (GIB) is a potentially serious and life-threatening condition in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, relatively little information is available regarding overt GIB in children. OBJECTIVES: To assess the prevalence, clinical patterns, and outcomes of overt GIB in children undergoing haploidentical hematopoietic stem cell transplantation (haplo-HSCT). METHODS: A total of 123 consecutive patients with malignant or non-malignant blood disorders who received haplo-HSCT were reviewed in our hospital between October 2017 and October 2022. Overt GIB was determined as hematemesis, melena or hematochezia. Continuous variables were compared by Mann Whitney U test. Categorical parameters were compared by the χ2 test or Fisher's exact test. Kaplan-Meier curves and log-rank tests were used to assess overall survival (OS), non-relapse mortality (NRM) and relapse. Univariate and multivariate analyses were performed to identify potential risk factors of overt GIB development. RESULTS: The median follow-up was 26.3 (range,1.7-74.8) months. Overt GIB occurred in 31 patients (25.2% incidence), with a median time elapsed after haplo-HSCT of 376 days (range, 58-1275 days). Compared with the non-GIB group, patients with overt GIB had reduced OS and increased NRM. In multivariate analysis, grade III-IV gut acute graft versus-host disease (aGvHD), thrombotic microangiopathy (TMA) and cytomegalovirus (CMV) viremia were significant risk factors for the occurrence of overt GIB after haplo-HSCT. CONCLUSIONS: Overt GIB is a frequent complication after haplo-HSCT in pediatric patients, and associated with worse survival. Grade III-IV gut aGvHD, TMA and CMV viremia were associated with its development.

ABO incompatibility haploidentical peripheral blood stem cell transplantation combined with a single cord blood unit for severe aplastic anemia patients.

Objective: To observe the efficacy of haploidentcial peripheral blood stem cell transplantation combined with a single unrelated cord blood unit for severe aplastic anemia patients with donor-recipient ABO incompatibility. Methods: This was a retrospective cohort study and data of 57 severe aplastic anemia patients underwent haploidentical stem cell transplantation from August 1, 2018 to February 28, 2022 in the First Affiliated Hospital of Xi'an Jiaotong University was retrospectively analyzed. All patients were divided into two groups, the donor-recipient ABO matched group (bone marrow+peripheral blood group) using haploidentical bone marrow and peripheral blood stem cells as grafts, and donor-recipient ABO mismatched group (cord blood+peripheral blood group), using unrelated cord blood and haploidentical peripheral blood stem cells as grafts. The differences of hematopoietic reconstitution, acute and chronic graft-versus-host disease, Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infection, and overall survival between the two groups were compared. Results: There were 30 cases in cord blood+peripheral blood group and 27 cases in bone marrow+peripheral blood group. One patient in bone marrow+peripheral blood group had primary graft failure, while other patients were successfully implanted. There were no significant differences of neutrophil and platelet recovery rates between two groups. The erythrocyte recovery time of cord blood+peripheral blood group was slower than that of bone marrow+peripheral blood group (p < 0.05). There was no significant difference of the incidence of graft-versus-host disease, CMV, EB virus infection and post-transplant lymphoproliferative disorders between two groups (p > 0.05). The incidence of grade III-IV acute graft-versus-host disease in cord blood+peripheral blood group was higher than that of bone marrow+peripheral blood group (p < 0.05). The incidence of intestinal graft-versus-host disease was higher in minor ABO-mismatched transplantation than that in major ABO-mismatched transplantation (p < 0.05). There was no significant difference of overall survival between two groups (p > 0.05). Conclusion: These findings suggest that haploidentical peripheral blood stem cell transplantation combined with a single cord blood unit may be an alternative option for severe aplastic anemia patients with donor-recipient ABO incompatibility.

[Clinical Observation on Haploid Hematopoietic Stem Cells Combined with Umbilical Cord Blood Double Transplantation for Aplastic Anaemia in Children].

OBJECTIVE: To explore the efficacy and safety of haploidentical hematopoietic stem cell transplantation combined with umbilical cord blood infusion for the treatment of aplastic anaemia in children. METHODS: Nine cases of children with aplastic anaemia treated with umbilical cord blood combined with haploidentical hematopoietic stem cell transplantation at the People's Hospital of Henan University of Chinese Medicine from January 1, 2021 to September 15, 2023 with a median age of 11(2-13) years and a median follow up of 18(7.5-21) months were included, and the clinical data were retrospectively analyzed. Hematopoiesis reconstitution, the incidence of graft-versus-host disease(GVHD), infections and survival of the patients were analyzed. RESULTS: All 9 children were successfully implanted. The median time to neutrophil and platelet implantation was 11.11±1.27 d and 12.44±3.36 d, respectively. One case developed acute gastrointestinal GVHD of degree I, which was improved after treatment, and the patient developed superficial gastritis and chronic gastrointestinal GVHD at a later stage, which is currently under clinical follow-up. Acute GVHD of II-IV degree was 0%. Hemorrhagic cystitis in 3 cases, CMV infection in 5 cases and bacterial and fungal infections in 5 cases improved with symptomatic treatment.All 9 children demonstrated complete donor chimerism within 1 month after transplantation, at two years of follow-up, all nine children survived without recurrence or development of grade II-IV GVHD, and there were no children with transplant-related deaths. CONCLUSION: Haploidentical hematopoietic stem cell transplantation combined with umbilical cord blood transfusion for aplastic anaemia in children has a low incidence and mild degree of GVHD, with significant efficacy, and can be used as a therapeutic option for children without an HLA full donor chimeric match.

Successful Treatment of Severe Steroid-Resistant Engraftment Syndrome Following Haploidentical Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia with Emapalumab: A Case Report.

Engraftment syndrome (ES) is an early complication of hematopoietic stem cell transplantation (HSCT) characterized by fever and additional clinical manifestations including rash, diarrhea, lung infiltrates, weight gain, and neurological symptoms. Steroid-resistant ES following HSCT significantly affects the efficacy of transplantation and may even result in patient mortality. As ES essentially represents a cytokine storm induced by engrafted donor cells with interferon-gamma (IFN-γ) playing a central role, we hypothesized that emapalumab (an anti-IFN-γ monoclonal antibody) may be an effective approach to treat steroid-resistant ES. Here, we present a case report of a 14-year-old female patient who received a second haploidentical HSCT due to a relapse of acute myeloid leukemia. Nine days after the transplantation, the patient developed a fever and exhibited a poor response to antimicrobials (ceftazidime/avibactam). A few days later, the patient presented with a new-onset rash, weight gain, and impaired liver function, leading to a diagnosis of ES. Initial immunosuppressive (tacrolimus and mycophenolate mofetil) treatment failed to control the disease. On day 16 post-transplantation, the patient received two infusions of 50 mg of emapalumab. Following the initiation of emapalumab treatment, the patient's fever returned to normal and ES was effectively controlled. This case report demonstrated that emapalumab had a possible efficacy for steroid-resistant ES and provided a novel therapeutic strategy to treat this clinical complication.

Memory T-cell enriched haploidentical transplantation with NK cell addback results in promising long-term outcomes: a phase II trial.

BACKGROUND: Relapse remains a challenge after transplantation in pediatric patients with hematological malignancies. Myeloablative regimens used for disease control are associated with acute and long-term adverse effects. We used a CD45RA-depleted haploidentical graft for adoptive transfer of memory T cells combined with NK-cell addback and hypothesized that maximizing the graft-versus-leukemia (GVL) effect might allow for reduction in intensity of conditioning regimen. METHODS: In this phase II clinical trial (NCT01807611), 72 patients with hematological malignancies (complete remission (CR)1: 25, ≥ CR2: 28, refractory disease: 19) received haploidentical CD34 + enriched and CD45RA-depleted hematopoietic progenitor cell grafts followed by NK-cell infusion. Conditioning included fludarabine, thiotepa, melphalan, cyclophosphamide, total lymphoid irradiation, and graft-versus-host disease (GVHD) prophylaxis consisted of a short-course sirolimus or mycophenolate mofetil without serotherapy. RESULTS: The 3-year overall survival (OS) and event-free-survival (EFS) for patients in CR1 were 92% (95% CI:72-98) and 88% (95% CI: 67-96); ≥ CR2 were 81% (95% CI: 61-92) and 68% (95% CI: 47-82) and refractory disease were 32% (95% CI: 11-54) and 20% (95% CI: 6-40). The 3-year EFS for all patients in morphological CR was 77% (95% CI: 64-87) with no difference amongst recipients with or without minimal residual disease (P = 0.2992). Immune reconstitution was rapid, with mean CD3 and CD4 T-cell counts of 410/µL and 140/µL at day + 30. Cumulative incidence of acute GVHD and chronic GVHD was 36% and 26% but most patients with acute GVHD recovered rapidly with therapy. Lower rates of grade III-IV acute GVHD were observed with NK-cell alloreactive donors (P = 0.004), and higher rates of moderate/severe chronic GVHD occurred with maternal donors (P = 0.035). CONCLUSION: The combination of a CD45RA-depleted graft and NK-cell addback led to robust immune reconstitution maximizing the GVL effect and allowed for use of a submyeloablative, TBI-free conditioning regimen that was associated with excellent EFS resulting in promising long-term outcomes in this high-risk population. The trial is registered at ClinicalTrials.gov (NCT01807611).

Dual T-cell depletion with individually tailored anti-thymocyte globulin and attenuated dose of post-transplant cyclophosphamide in haploidentical peripheral stem cell transplantation.

This study aimed to assess the efficacy of dual T-cell suppression using individually tailored doses of antithymocyte globulin (ATG) and attenuated dose of post-transplant cyclophosphamide (PTCy) in haploidentical hematopoietic stem cell transplantation (haplo-HSCT). We conducted a retrospective analysis of 78 adults with acute leukemia or myelodysplastic syndrome who underwent haplo-HSCT using intravenous busulfan and fludarabine conditioning. Thirty-two patients received attenuated ATG/PTCy, while 46 patients received ATG (7.5 mg/kg) as GVHD prophylaxis. The 100-day cumulative incidence of grade III-IV (9.7% vs. 32.4%, P = 0.018) acute GVHD, as well as 2-year moderate-severe chronic GVHD (13.9% vs. 43.9%, P = 0.018) in the ATG/PTCy group were significantly lower than those in the ATG group. The 2-year overall survival was comparable between the two groups. However, 2-year GVHD-free, relapse-free survival in the ATG/PTCy group was significantly higher compared to that in the ATG group (38.9% vs. 21.7%, P = 0.021). Moreover, during post-engraftment period, the ATG/PTCy group exhibited lower incidences of life-threatening bacterial (12.5% vs. 37%, P = 0.033) and viral infection (0% vs. 17.4%, P = 0.035) than the ATG group. In conclusion, the combination of individually tailored ATG and low-dose PTCy appears to be a promising strategy in haplo-HSCT.

SOHO State of the Art Updates and Next Questions | Current Status and Future Directions of Donor Selection.

The landscape of HLA matching in hematopoietic cell transplantation (HCT) is continuously advancing, introducing more nuanced criteria beyond traditional 10/10 HLA-A, -B, -C, and -DRB1 allele matching. For 10/10 matched donors, prioritizing a donor with a "core" permissive HLA-DPB1 mismatch is recommended over "noncore" permissive mismatches, with nonpermissive mismatches being the least prefered. In the one-antigen mismatched setting (7/8 HLA-matched), HLA-C matching, particularly avoiding high-expression mismatches at residues 116 or 77/80, is preferred over HLA-A or HLA-B mismatches. HLA B-leader matching is beneficial in both one-antigen mismatched and haploidentical HCT. Additionally, specific HLA mismatches in haploidentical HCT, such as DRB1 mismatches with DQB1 matches and DPB1 nonpermissive mismatches are linked to better outcomes. Among non-HLA factors, evidence consistently underscores the pivotal impact of donor age on overall survival. For HLA-mismatched transplants, including haploidentical HCT, avoidance of donors against whom the recipient has preformed donor-specific antibodies is paramount. Selecting a cytomegalovirus (CMV) seronegative donor is important particularly for CMV-negative recipients; however, more research is needed in the letermovir prophylaxis era. The impact of ABO-matching on transplant outcomes is debatable. Other unanswered questions include defining "younger" donors and establishing hierarchy in donor selection based on factors like CMV status, ABO compatibility, or sex-mismatch, to name a few. Future research addressing these issues will refine donor selection algorithms and improve transplant success. In conclusion, selecting a donor for HCT requires multifaceted considerations, integrating evolving HLA-matching criteria and non-HLA factors, to optimize HCT outcomes in this rapidly advancing field.

Future directions in haploidentical hematopoietic stem cell transplantation.

Outcomes of haploidentical hematopoietic stem cell transplantation (haplo-SCT) have improved over time. Graft failure and graft-versus-host disease (GVHD), which were important complications in major human leukocyte antigen (HLA)-disparity stem cell transplantation, have significantly decreased. These improvements have led to an exponential increase in the use of haploidentical donors for transplantation, as well as in the number of publications evaluating haplo-SCT outcomes. Many studies focused on factors important in donor selection, novel conditioning regimens or GVHD prophylaxis, the impact of donor-specific anti-HLA antibodies (DSA), as well as strategies to prevent disease relapse post-transplant. DSA represents an important limitation and multimodality desensitization protocols, including plasma exchange, rituximab, intravenous immunoglobulin and donor buffy coat infusion, can contribute to the successful engraftment in patients with high DSA levels and is currently the standard therapy for highly allosensitized individuals. With regards to donor selection, younger donors are preferred due to lower risk of complications and better transplant outcomes. Moreover, recent studies also showed that younger haploidentical donors may be a better choice than older-matched unrelated donors. Improvement of disease relapse remains a top priority, and several studies have demonstrated that higher natural killer (NK) cell numbers early post-transplant are associated with improved outcomes. Prospective studies have started to assess the role of NK cell administration in decreasing post-transplant relapse. These studies suggest that the incorporation of other cell products post-transplant, including the administration of chimeric antigen receptor T-cells, should be explored in the future.