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Abstract Introduction In vitro or in vivo depletion of alloreactive T cells can facilitate haplo-identical hematopoietic stem cell transplantation (HSCT). Very satisfactory transplant outcomes were thus reported for TCRαβ/CD19-depleted hematopoietic stem/progenitor cell (HSPC) grafts. The current semi-automatic manufacturing process on the CliniMACS Plus, although robust, still requires a significant amount of manual labor to be completed. Towards advancing and further facilitating large scale cell processing, a new TCRαβ/CD19 depletion module combined with the previously described CD45RA depletion module (to serve as allo-reactivity attenuated donor lymphocyte infusion) was established on the CliniMACS Prodigy. Methods We evaluated six apheresis products from G-CSF-mobilized volunteer donors which were split automatically by the Prodigy, one portion each depleted of CD45RA+ or of TCRαβ+ and CD19+ cells. We investigated critical quality attributes for both products. Products were assessed for recovery of HSPCs and mature subsets, as well as depletion efficiency of targeted cells using flow cytometry. Effects of apheresis and product age post 48 h storage at 2–6 °C as well as freeze-thawing on product viability and recovery of WBC and HPSCs were assessed by flow cytometry. Results Ten sequential automatic processes were completed with minimal hands-on time beyond tubing set installation. Depletion efficiency of CD45RA+ resp. TCRαβ+ and CD19+ cells was equivalent to previous reports, achieving mean depletions of 4 log of targeted cells for both products. HSPC products retained TCRγδ+ and NK cells. 48 h storage of apheresis product was associated with the expected modest loss of HSPCs, but depletions remained efficient. Depleted products were stable until at least 72 h after apheresis with stem cell viabilities > 90%. Freeze-thawing resulted in loss of NK cells; post-thaw recovery of viable CD45+ and HSPCs was > 70% and in line with expectation. Conclusion The closed, GMP-compatible process generates two separate medicinal products from the same mobilized apheresis product. The CD45RA-depleted products contained functional memory T cells, whereas the TCRαβ/CD19-depleted products included HSPCs, TCRγδ+ and NK cells. Both products are predicted to be effectively depleted of GVH-reactivity while providing immunological surveillance, in support of haplo-identical HSCT. Graphical Abstract

Introduction: In vitro or in vivo depletion of alloreactive T cells can facilitate haplo-identical hematopoietic stem cell transplantation (HSCT). Very satisfactory transplant outcomes were thus reported for TCRαβ/CD19-depleted hematopoietic stem/progenitor cell (HSPC) grafts. The current semi-automatic manufacturing process on the CliniMACS Plus, although robust, still requires a significant amount of manual labor to be completed. Towards advancing and further facilitating large scale cell processing, a new TCRαβ/CD19 depletion module combined with the previously described CD45RA depletion module (to serve as allo-reactivity attenuated donor lymphocyte infusion) was established on the CliniMACS Prodigy. Methods: We evaluated six apheresis products from G-CSF-mobilized volunteer donors which were split automatically by the Prodigy, one portion each depleted of CD45RA+ or of TCRαβ+ and CD19+ cells. We investigated critical quality attributes for both products. Products were assessed for recovery of HSPCs and mature subsets, as well as depletion efficiency of targeted cells using flow cytometry. Effects of apheresis and product age post 48 h storage at 2–6 °C as well as freeze-thawing on product viability and recovery of WBC and HPSCs were assessed by flow cytometry. Results: Ten sequential automatic processes were completed with minimal hands-on time beyond tubing set installation. Depletion efficiency of CD45RA+ resp. TCRαβ+ and CD19+ cells was equivalent to previous reports, achieving mean depletions of 4 log of targeted cells for both products. HSPC products retained TCRγδ+ and NK cells. 48 h storage of apheresis product was associated with the expected modest loss of HSPCs, but depletions remained efficient. Depleted products were stable until at least 72 h after apheresis with stem cell viabilities > 90%. Freeze-thawing resulted in loss of NK cells; post-thaw recovery of viable CD45+ and HSPCs was > 70% and in line with expectation. Conclusion: The closed, GMP-compatible process generates two separate medicinal products from the same mobilized apheresis product. The CD45RA-depleted products contained functional memory T cells, whereas the TCRαβ/CD19-depleted products included HSPCs, TCRγδ+ and NK cells. Both products are predicted to be effectively depleted of GVH-reactivity while providing immunological surveillance, in support of haplo-identical HSCT. [ABSTRACT FROM AUTHOR]

Simple Summary: Natural killer (NK) cells are key cytotoxic effectors against leukemic cells. The polymorphism of killer cell immunoglobulin-like receptor (KIR) genes plays a crucial role in the NK cell repertoire. In particular, different levels of KIR3DL1 expression on the NK cell surface are described, discriminating non-expressed vs. expressed allotypes depending on the KIR3DL1 alleles. KIR3DL1 allelic polymorphism after T-replete haploidentical hematopoietic stem cell transplantation (hHSCT) has not yet been investigated. In this study, we first assessed the extent of non-expressed versus expressed KIR3DL1 allotypes in a cohort of healthy blood donors and then evaluated their clinical impact on relapse incidence after hHSCT. Overall, we would expect that taking KIR3DL1 allelic polymorphism into consideration could help to refine the scores used for HSC donor selection. KIR3DL1 alleles are expressed at different levels on the natural killer (NK) cell surface. In particular, the non-expressed KIR3DL1*004 allele appears to be common in Caucasian populations. However, the overall distribution of non-expressed KIR3DL1 alleles and their clinical relevance after T-replete haploidentical hematopoietic stem cell transplantation (hHSCT) with post-transplant cyclophosphamide remain poorly documented in European populations. In a cohort of French blood donors (N = 278), we compared the distribution of expressed and non-expressed KIR3DL1 alleles using next-generation sequencing (NGS) technology combined with multi-color flow cytometry. We confirmed the predominance of the non-expressed KIR3DL1*004 allele. Using allele-specific constructs, the phenotype and function of the uncommon KIR3DL1*019 allotype were characterized using the Jurkat T cell line and NKL transfectants. Although poorly expressed on the NK cell surface, KIR3DL1*019 is retained within NK cells, where it induces missing self-recognition of the Bw4 epitope. Transposing our in vitro observations to a cohort of hHSCT patients (N = 186) led us to observe that non-expressed KIR3DL1 HSC grafts increased the incidence of relapse in patients with myeloid diseases. Non-expressed KIR3DL1 alleles could, therefore, influence the outcome of hHSCT. [ABSTRACT FROM AUTHOR]

Currently, the graft-versus-host disease (GVHD) prophylaxis consists of an immunosuppressive therapy mainly based on antithymocyte globulin (ATG) or post-transplant cyclophosphamide (PTCy). GVHD remains a major complication and limitation to successful allogeneic haploidentical hematopoietic stem cell transplantation (haplo-HSCT). We modified the ATG-based GVHD prophylaxis with the addition of basiliximab in the setting of haplo-HSCT and attempted to explore the appropriate dosages. We conducted a retrospective analysis of 239 patients with intermediate- or high-risk hematologic malignancies who received haplo-HSCT with unmanipulated peripheral blood stem cells combined or not with bone marrow. All patients received the same GVHD prophylaxis consisting of the combination of methotrexate, cyclosporine or tacrolimus, mycofenolatemofetil, and basiliximab with different doses of ATG (5-9mg/kg). With a median time of 11 days (range, 7-40 days), the rate of neutrophil engraftment was 96.65%. The 100-day cumulative incidences (CIs) of grade II-IV and III-IV aGVHD were 15.8 ± 2.5% and 5.0 ± 1.5%, while the 2-year CIs of total cGVHD and extensive cGVHD were 9.8 ± 2.2% and 4.1 ± 1.5%, respectively. The 3-year CIs of treatment-related mortality (TRM), relapse, overall survival (OS), and disease-free survival (DFS) were 14.6 ± 2.6%, 28.1 ± 3.4%, 60.9 ± 3.4%, 57.3 ± 3.4%, respectively. Furthermore, the impact of the reduction of the ATG dose to 6 mg/kg or less in combination with basiliximab on GVHD prevention and transplant outcomes among patients was analyzed. Compared to higher dose of ATG(>6mg/kg), lower dose of ATG (≤6mg/kg) was associated with a significant reduced risk of CMV viremia (52.38% vs 79.35%, P<0.001), while the incidences of aGVHD and cGVHD were similar between the two dose levels. No significant effect was found with regard to the risk of relapse, TRM, and OS. ATG combined with basiliximab could prevent GVHD efficiently and safely. The optimal scheme of using this combined regimen of ATG and basiliximab is that administration of lower dose ATG (≤6mg/kg), which seems to be more appropriate for balancing infection control and GVHD prophylaxis. [ABSTRACT FROM AUTHOR]

Introduction: Chimeric antigen receptor (CAR) T-cell (CAR-T) therapy followed by haploidentical hematopoietic stem cell transplantation (haplo-HSCT) markedly improves the long-term survival of patients with refractory/relapsed (R/R) B-cell acute lymphoblastic leukemia (B-ALL). Methods: We performed a parallel comparison of transplant outcomes in 168 B-ALL patients undergoing haplo-HSCT after achieving minimal residual disease (MRD)-negative complete remission (CR) from CAR-T therapy (n = 28) or chemotherapy (n = 140) between January 2016 and August 2021. We further divided the chemotherapy group into the first CR group (chemo+CR1, n = 118) and a second or more CR group (chemo+=CR2, n = 22). Results: With a median follow-up period of 31.0 months, the 2-year overall survival (OS), leukemia-free survival (LFS), non-relapse mortality (NRM), and relapse rates in the CAR-T and chemotherapy groups did not differ significantly (OS, 87.9% vs. 71.5 %; LFS, 72.0% vs. 66.8%; NRM, 3.9% vs. 13.7%; relapse, 24.1% vs. 19.4%). Multivariate analysis confirmed that =CR2 at transplantation following chemotherapy was an independent risk factor associated with poor OS (hazard ratio (HR) 4.22 [95% CI, 1.34-13.293], p = 0.014) and LFS (HR 2.57 [95% CI, 1.041-6.343], p = 0.041). The probabilities of OS and LFS at 2 years in the CAR-T group were comparable to those in the chemo+CR1 group but significantly higher than those in the chemo+=CR2 group (OS, 87.9% vs. 37.8%, p = 0.007; LFS, 72.0% vs. 41.7%, p = 0.043). No significant differences in the incidences of NRM were noted among the three groups. Conclusions: Our results demonstrated that patients with R/R B-ALL receiving haplo-HSCT after CAR-T therapy achieved comparable outcomes to patients transplanted post-chemotherapy-based MRD-negative CR1, without increased risk of transplant-related mortality and toxicity. [ABSTRACT FROM AUTHOR]

IntroductionChimeric antigen receptor (CAR) T-cell (CAR-T) therapy followed by haploidentical hematopoietic stem cell transplantation (haplo-HSCT) markedly improves the long-term survival of patients with refractory/relapsed (R/R) B-cell acute lymphoblastic leukemia (B-ALL).MethodsWe performed a parallel comparison of transplant outcomes in 168 B-ALL patients undergoing haplo-HSCT after achieving minimal residual disease (MRD)-negative complete remission (CR) from CAR-T therapy (n = 28) or chemotherapy (n = 140) between January 2016 and August 2021. We further divided the chemotherapy group into the first CR group (chemo+CR1, n = 118) and a second or more CR group (chemo+≥CR2, n = 22).ResultsWith a median follow-up period of 31.0 months, the 2-year overall survival (OS), leukemia-free survival (LFS), non-relapse mortality (NRM), and relapse rates in the CAR-T and chemotherapy groups did not differ significantly (OS, 87.9% vs. 71.5 %; LFS, 72.0% vs. 66.8%; NRM, 3.9% vs. 13.7%; relapse, 24.1% vs. 19.4%). Multivariate analysis confirmed that ≥CR2 at transplantation following chemotherapy was an independent risk factor associated with poor OS (hazard ratio (HR) 4.22 [95% CI, 1.34–13.293], p = 0.014) and LFS (HR 2.57 [95% CI, 1.041–6.343], p = 0.041). The probabilities of OS and LFS at 2 years in the CAR-T group were comparable to those in the chemo+CR1 group but significantly higher than those in the chemo+≥CR2 group (OS, 87.9% vs. 37.8%, p = 0.007; LFS, 72.0% vs. 41.7%, p = 0.043). No significant differences in the incidences of NRM were noted among the three groups.ConclusionsOur results demonstrated that patients with R/R B-ALL receiving haplo-HSCT after CAR-T therapy achieved comparable outcomes to patients transplanted post-chemotherapy-based MRD-negative CR1, without increased risk of transplant-related mortality and toxicity.

Sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a life-threatening complication after both autologous and allogeneic hematopoietic stem cell transplantation (HSCT). However, its characterization after haploidentical HSCT (haplo-HSCT) with post-transplantation cyclophosphamide (PT-Cy) is scarce. This study aimed to describe characteristics and outcomes of patients with SOS/VOD after haplo-HSCT with PT-Cy. We conducted a retrospective study of 797 patients undergoing a haplo-HSCT with PT-Cy between 2007 and 2019 in 9 centers in Spain. SOS/VOD was defined according to modified Seattle, Baltimore, or revised European Society for Blood and Marrow Transplantation (EBMT) criteria. Severity was graded retrospectively according to revised EBMT severity criteria into 4 categories: mild, moderate, severe, and very severe. From a total of 797 haplo-HSCTs performed, 46 patients (5.77%) were diagnosed with SOS/VOD at a median of 19 days (range, 4 to 84 days) after transplantation. Based on revised EBMT severity criteria, the SOS/VOD cases were classified as mild (n = 4; 8.7%), moderate (n = 10; 21.7%), severe (n = 12; 26.1%), and very severe (n = 20; 43.5%). Overall, 30 patients (65%) achieved SOS/VOD complete response, 25 (83%) of whom were treated with defibrotide. Twenty patients (43%) died before day +100 post-HSCT. Death was attributed to SOS/VOD in 11 patients, and 5 patients died of other causes without resolution of SOS/VOD. The incidence of SOS/VOD after haplo-HSCT with PT-Cy was comparable to those reported after HLA-identical HSCT series. Most of the patients developed very severe SOS/VOD according to revised EBMT severity criteria. Despite a promising SOS/VOD complete response (CR) rate (65%), 100-day mortality remained high (43%), indicating that further improvement in the management of this potentially fatal complication is needed., (Copyright © 2024 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Despite the great advances in immunosuppressive therapy for severe aplastic anemia (SAA), most patients are not completely cured. Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has been recommended as an alternative treatment in adult SAA patients. However, haplo-HSCT presents a higher incidence of graft failure and graft-versus-host disease (GVHD). The authors designed a combination of haplo-HSCT and umbilical cord-derived mesenchymal stem cells (UC-MSCs) for treatment of SAA in adult patients and evaluated its effects. Adult patients (≥18 years) with SAA (N = 25) were given HLA-haploidentical hematopoietic stem cells (HSCs) combined with UC-MSCs after a conditioning regimen consisting of busulfan, cyclophosphamide, fludarabine and anti-thymocyte globulin and intensive GVHD prophylaxis, including cyclosporine, basiliximab, mycophenolate mofetil and short-term methotrexate. Additionally, the effects of the protocol in adult SSA patients were compared with those observed in juvenile SAA patients (N = 75). All patients achieved myeloid engraftment after haplo-HSCT at a median of 16.12 days (range, 11–26). The median time of platelet engraftment was 28.30 days (range, 13–143). The cumulative incidence of grade II acute GVHD (aGVHD) at day +100 was 32.00 ± 0.91%. No one had grade III–IV aGVHD at day +100. The cumulative incidence of total chronic GVHD was 28.00 ± 0.85%. The overall survival was 71.78 ± 9.05% at a median follow-up of 42.08 months (range, 2.67–104). Promisingly, the protocol yielded a similar curative effect in both young and adult SAA patients. The authors' data suggest that co-transplantation of HLA-haploidentical HSCs and UC-MSCs may provide an effective and safe treatment for adult SAA. [ABSTRACT FROM AUTHOR]

We aimed to analyze data in children with primary hemophagocytic lymphohistiocytosis (HLH) who underwent hematopoietic stem cell transplantation (HSCT). We performed a retrospective study where children up to 18 years, with primary HLH and who underwent HSCT from January 2011 to December 2019, were included. Twenty-five children with genetic HLH underwent HSCT, including variants (Griscelli syndrome (GS2) 7, Chediak–Higashi syndrome (CHS) 2, XIAP mutation 2). Donors were matched family 8 (32%), umbilical cord blood unit 3 (12%), matched unrelated 2 (8%), haploidentical HSCT 12 (48%), (TCR alpha/beta depletion 2 and post-transplant cyclophosphamide 10). With treosulfan-based conditioning, engraftment was achieved in 23/25 (92%) transplants (100% in haplo-HSCT), with sustained complete chimerism in 87%. Disease-free survival was noted in 2/3 children with stable mixed chimerism. Graft-versus-host disease (GVHD) of grade I/II was noted in 6 (24%), grade III in 3 (13%); chronic limited skin GVHD in 2 (12%) children. Overall survival was 72% (87.5% in matched donor, 66.7% in the haplo-HSCT), 71% in GS2, 50% in CHS, 100% in XIAP. HSCT is curative in primary HLH with acceptable disease-free survival with mixed chimerism. Haplo-HSCT is a viable option for those without matched family or unrelated donors. [ABSTRACT FROM AUTHOR]

Background: Haploidentical HSCT is a good option for children with PIDs lacking an HLA‐matched donor. Co‐transplantation of MSCs during haploidentical HSCT in patients with PIDs may enhance engraftment, decrease the risk of GVHD, and ensure stable donor chimerism. Methods: Twenty‐seven pediatric patients (median age, 1.4 years; range,.3–10.9) with PIDs undergoing thirty haploidentical HSCT with TCR αβ depletion and co‐transplantation of MSCs were enrolled to study. Most patients (73.3%) received myeloablative conditioning consisting of treosulfan or busulfan, fludarabine, and thiotepa. The median duration of follow‐up was 14.3 months (range, 1–69 months). Results: Acute GVHD occurred in 7 patients (grade I‐II n = 5, grade III‐IV n = 2). Chronic GVHD was observed in only one patient. Twenty‐one patients (70.2%) had 100% donor chimerism in all cell lines including T‐cell and B‐cell lineages. Primary graft failure was observed in 7 patients (25.9%). The cumulative incidences of TRM were 20% at day 100, and 26.7% at one year and five years. Probabilities of OS were 80% at day 100, and 71.9% at 1 year and 5 years. Infants transplanted younger than 6 months of age had the highest 5‐year survival rate (85.7%). Conclusion: We conclude that use of TCR αβ depleted haploidentical transplantation with MSCs may ensure a rapid engraftment rate, low incidence of significant acute and chronic GVHD, and acceptable post‐transplantation morbidity, especially in patients diagnosed with SCID and may be considered in children with PIDs. In younger patients (≤6 months), survival is comparable between HLA‐matched graft and CD3+ TCRαβ depleted HLA‐mismatched graft recipients. [ABSTRACT FROM AUTHOR]

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is a widely available curative option for patients with sickle cell disease (SCD). Our original non-myeloablative haplo-HSCT trial employing post-transplant (PT) cyclophosphamide had a low incidence of GVHD but had high rejection rates. Here, we aimed to evaluate immune reconstitution following haplo-HSCT and identify cytokines and cells associated with graft rejection/engraftment. 50 cytokines and 10 immune cell subsets were screened using multiplex-ELISA and flow cytometry, respectively, at baseline and PT-Days 30, 60, 100, and 180. We observed the most significant differences in cytokine levels between the engrafted and rejected groups at PT-Day 60, corresponding with clinical findings of secondary graft rejection. Of the 44 cytokines evaluated, plasma concentrations of 19 cytokines were different between the two groups at PT-Day 60. Factor analysis suggested two independent factors. The first factor (IL-17A, IL-10, IL-7, G-CSF, IL-2, MIP-1a, VEGF, and TGFb1 contributed significantly) was strongly associated with engraftment with OR = 2.7 (95%CI of 1.4 to 5.4), whereas the second factor (GROa and IL-18 contributed significantly) was not significantly associated with engraftment. Sufficient donor myeloid chimerism (DMC) is critical for the success of HSCT; here, we evaluated immune cells among high (H) DMC (DMC≥20%) and low (L) DMC (DMC

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is a widely available curative option for patients with sickle cell disease (SCD). Our original non-myeloablative haplo-HSCT trial employing post-transplant (PT) cyclophosphamide had a low incidence of GVHD but had high rejection rates. Here, we aimed to evaluate immune reconstitution following haplo-HSCT and identify cytokines and cells associated with graft rejection/engraftment. 50 cytokines and 10 immune cell subsets were screened using multiplex-ELISA and flow cytometry, respectively, at baseline and PT-Days 30, 60, 100, and 180. We observed the most significant differences in cytokine levels between the engrafted and rejected groups at PT-Day 60, corresponding with clinical findings of secondary graft rejection. Of the 44 cytokines evaluated, plasma concentrations of 19 cytokines were different between the two groups at PT-Day 60. Factor analysis suggested two independent factors. The first factor (IL-17A, IL-10, IL-7, G-CSF, IL-2, MIP-1a, VEGF, and TGFb1 contributed significantly) was strongly associated with engraftment with OR = 2.7 (95%CI of 1.4 to 5.4), whereas the second factor (GROa and IL-18 contributed significantly) was not significantly associated with engraftment. Sufficient donor myeloid chimerism (DMC) is critical for the success of HSCT; here, we evaluated immune cells among high (H) DMC (DMC≥20%) and low (L) DMC (DMC<20%) groups along with engrafted and rejected groups. We found that early myeloid-derived suppressor cell (eMDSC) frequencies were elevated in engrafted patients and patients with HDMC at PT-Day 30 (P< 0.04 & P< 0.003, respectively). 9 of 20 patients were evaluated for the source of eMDSCs. The HDMC group had high mixed chimeric eMDSCs as compared to the LDMC group (P< 0.00001). We found a positive correlation between the frequencies of eMDSCs and Tregs at PT-Day 100 (r=0.72, P <0.0007); eMDSCs at BSL and Tregs at PT-Day 100 (r=0.63, P <0.004). Of 10 immune regulatory cells and 50 cytokines, we observed mixed chimeric eMDSCs and IL-17A, IL-10, IL-7, G-CSF, IL-2, MIP-1a, VEGF, TGFb1 as potential hits which could serve as prognostic markers in predicting allograft outcome towards engraftment following haploidentical HSCT employing post-transplant cyclophosphamide. The current findings need to be replicated and further explored in a larger cohort. [ABSTRACT FROM AUTHOR]

Background: We aimed to describe an algorithm for the management of cytokine release syndrome (CRS) associated with haploidentical hematopoietic stem cell transplantation (haploSCT). Patients and methods: We performed a prospective study where children up to 18 years of age undergoing haploSCT with post‐transplant cyclophosphamide from September 2014 to March 2020 were included. Supportive care included low‐dose adrenaline, high‐flow nasal cannula, and N‐acetylcysteine (NAC). Methylprednisolone and tocilizumab were administered in the peri‐engraftment phase for grade 2 CRS or one‐log increase and grade 3 CRS or a two‐log increase in ferritin, respectively. Results: Data were analyzed in 135/148 children as 13 children died before engraftment due to sepsis. CRS was noted in 97% transplants (grade 1—74.1%, grade 2—15.6%, grade 3—6.7%, grade 4—1.4%). Grade 2 and above CRS was higher in non‐malignant conditions (33% vs 13%, P‐value.009). The percentage median rise in ferritin was 129%—grade 1, 171%—grade 2, and 344%—grade 3. Seven children received tocilizumab, and two of whom had ferritin values greater than 100 000 ng/mL with no mortality in this group. Low‐dose adrenaline, high‐flow nasal cannula, and ventilator support were needed in 13%, 10%, and 4%, respectively. Mortality in our cohort was 3/135 (2.2%), with two deaths due to sepsis and one due to grade 4 CRS. Conclusions: A risk‐stratified approach using steroids in grade 2 and tocilizumab in grade 3/4 in the setting of haploSCT with NAC infusion and early use of low‐dose adrenaline and HFNC can help provide adequate control of CRS, thereby ensuring optimal outcomes and survival. [ABSTRACT FROM AUTHOR]

Background: We present comparative data of children with Fanconi anemia undergoing haploidentical hematopoietic stem cell transplantation (HSCT) with or without the addition of rabbit anti-thymocyte globulin (r-ATG) to the conditioning regimen., Patients and Methods: This retrospective study included children with Fanconi anemia aged up to 18 years who underwent haploidentical HSCT between January 2015 and December 2022. The children were included in two cohorts in this study. Cohort 1 included children who received conditioning with fludarabine/cyclophosphamide/single fraction of 2 Gy TBI. The children in cohort 2 received the same conditioning along with r-ATG. Post-transplant cyclophosphamide was administered at a dose of 25 mg/kg on day3 and day4 in both cohorts., Results: A total of 35 children were included in the study, 25 in cohort 1 and 10 in cohort 2. Neutrophil engraftment was documented around day 14-16 post infusion in 21 children (84%) in cohort 1 and in 8 children (80%) in cohort 2. There was a significant difference in the incidence of the severity of graft versus host disease (GVHD) between the two cohorts ( p = 0.003). In cohort 1, acute GVHD was documented in 17 children (68%), with grade 1/2 skin GVHD in 10 children, and grade 3/4 skin and gut GVHD in 7 children. Grade 4 gut GVHD was the cause of death in three children in cohort 1. In cohort 2, acute GVHD was documented in one child (10%) who had grade 4 skin and gut GVHD and succumbed to the above. Chronic GVHD was noted in nine (36%) children in cohort 1, and in one child (10%) in cohort 2. Cytomegalovirus reactivation was documented in 11 children (44%) in cohort 1 and three children (30%) in cohort 2. Overall survival was found to be 16/25 (64%) in cohort 1, with a median follow-up of 49 months, and 7/10 (70%) in cohort 2, with a median follow-up of 12 months., Conclusion: Serotherapy with r-ATG significantly reduced the incidence of GVHD from 68% to 10% in children with Fanconi anemia, with an increase in overall survival from 64% to 70%, although it did not affect graft failure. Further studies should focus on decreasing graft failure rates with early HSCT before multiple transfusions., Competing Interests: The authors declare no conflict of interest. Disclosure forms provided by the authors are available on the website., (Copyright Ⓒ2024 Asia-Pacific Blood and Marrow Transplantation Group (APBMT).)

Hepatic veno-occlusive disease or sinusoidal obstruction syndrome (VOD/SOS) is a threatening complication after both autologous and allogeneic hematopoietic stem cell transplantation (HSCT), with high mortality rates despite early medical treatment, including the use of defibrotide (DF). We retrospectively analyzed 185 unmanipulated haploidentical (haplo-) HSCT with post-transplantation cyclophosphamide as graft-versus-host disease prophylaxis performed consecutively between 2011 and June 2019 in a single center. Seventeen patients (9.2%) were diagnosed with VOD/SOS. Based on revised European Society for Blood and Marrow Transplantation severity criteria, the VOD/SOS cases were classified as mild in 2 patients (11.7%), moderate in 2 (11.7%), severe in 2 (11.7%), and very severe in 11 (64.9%). Thirteen patients (76%) were treated with DF, including all patients with severe or very severe VOD/SOS, except 1 patient with CNS hemorrhage. Sixteen patients (94%) were alive at day +100 after HSCT. Seven patients (41%) with very severe VOD/SOS were treated with transjugular intrahepatic portosystemic shunt (TIPS) owing to rapid clinical or analytical deterioration or refractory hepatorenal syndrome despite medical treatment, including DF. TIPS insertion was performed at a median time since VOD/SOS diagnosis of 4 days (range, 1 to 28 days) without technical complications in any case. The median hepatic venous pressure gradient before and after TIPS treatment was 24 mmHg (range, 14 to 29 mmHg) and 7 mmHg (range, 2 to 11 mmHg), respectively, with a median drop of 16 mmHg (range, 9 to 19 mmHg). Following TIPS insertion, all patients showed clinical improvement with hepatomegaly, ascites, and renal failure resolution, and all showed analytical improvement with reduced alanine aminotransferase (ALT), creatinine, and international normalized ratio values, except for patient 2, whose indication for TIPS was refractory hepatorenal syndrome with a normal ALT level. The 6 patients who had initiated DF before TIPS insertion completed 21 days of treatment. All patients met the criteria for complete remission (CR) at a median of 8 days after TIPS insertion (range, 2 to 82 days). The 100-day overall survival was 100%. For patients with rapid progressive VOD/SOS, early TIPS insertion allowed completion of DF therapy. The use of TIPS together with DF resulted in CR and no associated complications with no VOD/SOS-associated mortality despite high severity. In our experience, timely and individualized use of TIPS significantly improves outcomes of very severe VOD/SOS after haplo-HSCT. Therefore, TIPS should be promptly considered in rapidly progressive cases. [ABSTRACT FROM AUTHOR]

Key Clinical Message The principal limitation of allogeneic hematopoietic stem cell transplantation except relapse remains the transplant-related mortality ( TRM). In addition to graft-versus-host disease ( Gv HD), infections contribute to TRM in many patients. We describe herein a case of an adult patient presenting 5 months after haplo-identical transplantation an isolated fulminant hepatitis due to adenovirus. [ABSTRACT FROM AUTHOR]

The outcomes of adult acute lymphoblastic leukemia (ALL) patients with chemotherapy or autologous hematopoietic stem cell transplantation (HSCT) are unsatisfactory. Therefore, allogeneic (allo) HSCT has been applied to those patients in first complete remission (CR1), and has shown a long-term survival rate of approximately 50 %. In terms of myeloablative conditioning (MAC) regimen, higher dose of cyclophosphamide (CY) and total body irradiation (TBI) (the standard CY + TBI) has been generally applied to allo HSCT. Other MAC regimens such as busulfan-based or etoposide-based regimens have also been used. Among those, medium-dose etoposide (ETP) in addition to the standard CY + TBI conditioning regimen appears to be promising for allo HSCT in adult ALL when transplanted in ALL patients aged under 50 years in CR1 and also in CR2, showing an excellent outcome without increasing relapse or transplant-related mortality (TRM) rates. By contrast, reduced-intensity conditioning (RIC) regimens have also been applied to adult ALL patients and favorable outcomes have been obtained; however, relapse and TRM rates remain high. Therefore, an allo HSCT conditioning regimen which deserves further study for adult ALL patients aged under 50 years in CR1 and CR2 appears to be medium-dose ETP + CY + TBI and RIC is suitable for patients aged over 50 years or for younger patients with comorbid conditions. On the contrary, new therapeutic strategies for adult ALL patients are increasingly utilized with better outcomes; namely, various tyrosine kinase inhibitors for Philadelphia chromosome (Ph)-positive ALL, human leukocyte antigen-haploidentical HSCT, and pediatric-inspired regimens for Ph-negative ALL. Therefore, the optimal treatment modality should be selected considering patient's age, Ph-positivity, donor availability, risk classification, efficacy, and safety. [ABSTRACT FROM AUTHOR]

The long-term outcome of allogeneic hematopoietic stem cell transplantation (HSCT) in chemorefractory acute myeloid leukemia (AML) remains suboptimal because of a high relapse rate. Enhancement of conditioning regimens by the incorporation of targeted anti-leukemia agents is a potential approach to improve the efficacy of HSCT. In a pilot trial and extended access cohort, we evaluated the safety and potential value of adding combinations of venetoclax and daratumumab to a preparative regimen among children with chemorefractory acute myeloid leukemia grafted with αβ T-cell-depleted peripheral blood stem cells. All 20 patients had active disease status of AML at the time of transplantation. The preparative regimen included myeloablative conditioning based on either total body irradiation or treosulfan. A haploidentical related donor was used as a graft source for all patients. Engraftment was not compromised, and no excess toxicity was noted. Minimal residual disease-negative complete remission was achieved in 17 patients (85%). The cumulative incidence of grade II to IV acute graft-versus-host disease (GVHD) was 17%, and the cumulative incidence of chronic GVHD was 7%. At 2 years, nonrelapse mortality was 10%, relapse incidence was 46%, event-free survival was 44%, and overall survival was 65%. Our data show the possibility of safely adding targeted agents to conditioning regimens; however, no evidence of a significant improvement in long-term transplantation outcomes in this cohort of patients was observed., (Copyright © 2022 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

In a cohort of β-Thalassemia (β-Thal) transplanted with haploidentical-HSCT we identified one transplanted patient characterized by persistent mixed chimerism (PMC) for several months after HSCT. In this unique β-Thal patient we assessed the donor engraftment overtime after transplantation, the potential loss of the non-shared HLA haplotype, and the presence of CD49b+LAG-3+T regulatory type 1 (Tr1) cells, previously demonstrated to be associated with PMC after HLA-related HSCT for β-Thal. The majority of the patient's erythrocytes were of donor origin, whereas T cells were initially mostly derived from the recipient, no HLA loss, but an increased frequency of circulating Tr1 cells were observed. For the first time, we showed that when the proportion of residual donor cells decreases, the frequency of CD49b+LAG-3+Tr1 cells declines, reaching the levels present in healthy subjects. These findings confirm previous results obtained in transplant related settings for β-Thal, and supported the central role of Tr1 cells in promoting and maintaining PMC after allo-HSCT. [ABSTRACT FROM PUBLISHER]

Clofarabine is a novel purine nucleoside analogue with immunosuppressive and anti-leukemic activity in acute lymphoblastic and myeloid leukemia (AML, ALL). This retrospective study was performed to evaluate the feasibility and anti-leukemic activity of a sequential therapy using clofarabine for cytoreduction followed by conditioning for haploidentical hematopoietic stem cell transplantation (HSCT) in patients with non-remission acute leukemia. Patients received clofarabine (5 × 30 mg/m IV) followed by a T cell replete haploidentical transplantation for AML ( n = 15) or ALL ( n = 3). Conditioning consisted of fludarabine, cyclophosphamide plus either melphalan, total body irradiation or treosulfan/etoposide. High-dose cyclophosphamide was administered for post-grafting immunosuppression. Neutrophil engraftment was achieved in 83 % and complete remission in 78 % at day +30. The rate of acute graft versus host disease (GvHD) grade II-IV was 22 %, while chronic GvHD occured in five patients (28 %). Non-relapse mortality (NRM) after 1 year was 23 %. At a median follow-up of 19 months, estimated overall survival and relapse-free survival at 1 year from haploidentical HSCT were 56 and 39 %, respectively. Non-hematological regimen-related grade III-IV toxicity was observed in ten patients (56 %) and included most commonly transient elevation of liver enzymes (44 %), mucositis (40 %), and skin reactions including hand-foot syndrome (17 %), creatinine elevation (17 %), and nausea/vomiting (17 %). The concept of a sequential therapy using clofarabine for cytoreduction followed by haploidentical HSCT proved to be feasible and allows successful engraftment, while providing an acceptable toxicity profile and anti-leukemic efficacy in patients with advanced acute leukemia. NRM and rate of GvHD were comparable to results after HSCT from HLA-matched donors. [ABSTRACT FROM AUTHOR]

Background and objectives Since HHV-6 reactivation after transplant has been reported to increase the risk of CMV infection, we tested this hypothesis in the HLA-haploidentical hematopoietic stem cell transplantation setting. Study design From February 2011 to October 2015, 75 patients received hematopoietic stem cell transplantation using a T-cell replete graft from a HLA-haploidentical donor at our Institution. Results Interestingly, 87% of HHV-6 reactivations were followed by a CMV reactivation, at a median of 15 days between the two viruses. Incidence of CMV reactivation was 14.5-fold higher in those patients with prior HHV-6 reactivation vs. those without it (p-value < 0.001). Conclusion The present results suggest that HHV-6 can be considered as a predicting indicator of cellular immunosuppression preceding the onset of CMV infection. [ABSTRACT FROM AUTHOR]

The use of alternative hematopoietic stem cell (HSC) donors has been witnessing important progress, mainly due to: (i) better HLA matching at the allelic level between donor and recipient in unrelated HSC transplantation (HSCT) translating into better patient outcome; (ii) better donor choice and patient selection in unrelated, often HLA-mismatched, cord blood transplantation and (iii) new strategies of adoptive cell therapy aimed at improving the results of T-cell-depleted haploidentical HSCT from a relative. Currently, it is possible to find an HSC donor for virtually almost all children with an indication to receive allogeneic HSCT and lacking an HLA-identical sibling. Each of the three options of HSCT from alternative donors has advantages and limitations. Therefore, any physician has to carefully evaluate, for each single pediatric patient in need of an allograft, all the possible alternatives to choose the best HSC donor, taking into account type of disease to be treated, urgency of transplantation, donor characteristics and center's experience. This review will analyze in detail the advantages and limitations of each of the three options of alternative donor HSCT and the main criteria to be used for choosing the most suitable donor for pediatric patients lacking an HLA-identical sibling.Bone Marrow Transplantation (2008) 41, 207–214; doi:10.1038/sj.bmt.1705963; published online 17 December 2007 [ABSTRACT FROM AUTHOR]

Clinical outcomes of hematopoietic stem cell transplantation (HSCT) using a haploidentical stem cell graft and an unrelated umbilical cord blood unit (haplo-cord HSCT) for the treatment of B cell acute lymphoblastic leukemia (B-ALL) remain unclear. This study was conducted to explore the clinical outcomes of haplo-cord HSCT in patients with B-ALL. A total of 112 B-ALL patients who underwent haplo-cord HSCT and 64 B-ALL patients who underwent haploidentical HSCT (haplo-HSCT) at our center between 2010 and 2020 were retrospectively included in this study, and clinical outcomes and prognostic factors were further analyzed. Of the 112 haplo-cord HSCT recipients, 106 (94.6%) achieved complete haploidentical chimerism and 6 (5.4%) had mixed cord blood chimerism. No differences in neutrophil and platelet recovery or in the incidences of graft-versus-host disease, cytomegalovirus/Epstein-Barr virus viremia, bloodstream infection, or hemorrhagic cystitis were observed between the haplo-cord HSCT and haplo-HSCT groups. Compared with the haplo-HSCT group, the haplo-cord HSCT group had a higher absolute number of CD3 + cells (P = .029) and a lower ratio of CD3 + CD4 + /CD3 + CD8 + cells (P = .049) at 1 month post-transplantation. Moreover, the haplo-cord HSCT group had lower minimal residual disease (MRD) levels at 1 month (P = .020) and 100 days (P = .038) post-transplantation and a better 3-year prognosis (overall survival, P = .016; disease-free survival, P = .041; cumulative incidence of relapse [CIR], P = .016). The CIRs in patients with adverse genomic features (P = .040) or flow cytometry-based MRD (FCM-MRD) ≥1 × 10 -4 (P = .033) were improved by haplo-cord HSCT. Multivariate analysis revealed that haplo-cord HSCT could independently improve the 3-year OS, DFS, and CIR of B-ALL patients (OS, P = .029; DFS, P = .024; CIR, P = .024). In addition, allo-HSCT at first complete remission was an independent parameter associated with 3-year OS for B-ALL patients (P = .014). An FCM-MRD ≥1 × 10 -4 pre-HSCT could independently predict unfavorable 3-year DFS and CIR (DFS, P = .020; CIR, P = .036) in B-ALL patients. Our data suggest that the use of haplo-cord HSCT can independently improve survival in patients with B-ALL., (Copyright © 2021 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Allogeneic hematopoietic stem cell transplantation (allo-HSCT), including haploidentical HSCT (haplo-HSCT), is a potentially curative treatment for several hematologic disorders. However, the occurrence of poor graft function (PGF) can lead to mortality. Advances in the use of novel conditioning regimens and strategies to improve engraftment while reducing PGF, are expected to improve outcomes. This review has examined recent evidence that will provide insights into reducing graft failure in haplo-HSCT. [ABSTRACT FROM AUTHOR]

Primary immunodeficiencies (PIDs) are inherited disorders of the immune system with allogeneic hematopoietic stem cell transplantation (HSCT) as the only curative treatment in some of them. In case an HLA-matched donor is not available, HSCT from a haploidentical family donor may be considered. We compared the outcomes of HSCT from HLA-matched unrelated or related donors (MUDs or MRDs) and mismatched related haploidentical donors (MMRDs) in patients with a variety of PIDs in 2 centers. A total of 44 pediatric patients were evaluated. We reviewed the outcomes of 25 children who underwent transplantation with HLA-matched grafts (MRD, n = 13; MUD, n = 12) and 19 patients receiving haploidentical stem cells. Bone marrow (BM) was transplanted in 85% (MRD) and 75% (MUD) of the matched cohort and peripheral blood stem cells (PBSCs) in 15% (MRD), 25% (MUD), and 100% (MMRD). All but 9 patients (MRD, n = 6; MMRD, n = 3) with severe combined immunodeficiency (SCID) received a chemotherapy-based conditioning regimen. Immune reconstitution of T, B, and natural killer cells was comparable for all groups with an advantage of recipients of MRD grafts in early CD4 reconstitution. However, deaths due to viral infections occurred more often in the haploidentical cohort. The disease-free survival was 91.7% (MRD), 66.7% (MUD), and 62.7% (MMRD), respectively. Grade II to IV acute graft-versus-host disease (GVHD) occurred in 15% (MRD), 8% (MUD), and 21% (MMRD) of the patients. Only 1 patient had severe grade IV GVHD in the MRD group, whereas no grade >II GVHD was observed in the MUD or MMRD cohort. These data indicate that in the absence of a suitable HLA-identical family donor, haploidentical HSCT may be a viable option for patients with life-threatening disease and urgent need of HSCT., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Allogeneic hematopoietic stem cell transplantation (HSCT) is, to date, the only curative treatment for sickle cell disease (SCD). Because an human leukocyte antigen (HLA)-matched sibling donor is not always available, alternative stem cell sources such as unrelated or haploidentical related donors have been explored. To date, few series of SCD patients transplanted with an unrelated donor, cord blood, and haploidentical related donor have been reported, but the high rates of rejection and chronic graft versus host disease have limited their widespread application. We describe the outcomes of a retrospective, registry-based, survey on 144 alternative donor HSCT performed for SCD in 30 European Society for Blood and Marrow Transplantation centers between 1999 and 2017. Data on 70 unrelated adult donors (49%), six cord blood (4%), and 68 haploidentical donors (47%; including post-HSCT Cy, ex vivo T-cell depleted, and other haplo-HSCTs) were reported and missing information was updated by the centers. Overall, 16% patients experienced graft failure, Grade II-IV acute GVHD at 100 days was 24%, whereas Grade III-IV was 10%. Chronic GVHD was observed in 24% (limited for 13 patients and extensive for 18 patients). Overall, the 3-year overall survival (OS) was 86% ± 3% and 3-year event-free survival (EFS; considering death and graft failure as events) was 72% ± 4%. We therefore conclude that alternative donor HSCT for SCD can be feasible but efforts in decreasing relapse and GVHD should be promoted to increase its safe and successful utilization. Moreover, a better knowledge of HLA matching and the tailoring of conditioning could help improve EFS and OS., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 King Faisal Specialist Hospital & Research Centre. Published by Elsevier Ltd. All rights reserved.)

The application of haploidentical hematopoietic stem cell transplantation (HSCT) with mesenchymal stem cell (MSC) infusion as a treatment regimen for severe aplastic anemia (SAA) has been reported to be efficacious in single-arm trials. However, it is difficult to assess without comparing the results with those from a first-line, matched-sibling HSCT. Herein, we retrospectively reviewed 91 patients with acquired SAA. They received HSCT from haploidentical donors combined with MSC transfer (HID group). We compared these patients with 103 others who received first-line matched-sibling HSCT (MSD group) to evaluate relative treatment efficacy. Compared with the patients in the MSD group, those in the HID group presented with higher incidences of grades II-IV and III-IV acute graft versus host disease (aGvHD) and chronic graft versus host disease (cGvHD) ( p  < 0.05). However, the incidence of myeloid and platelet engraftment, graft failure, poor graft function, and extensive cGvHD were comparable for both groups. The median follow-up was 36.6 months and the 3-year overall survival rate was similar for both groups (83.5% versus 79.1%). Univariate and multivariate analyses revealed that time intervals greater than 4 months from diagnosis to transplantation, experienced graft failure, poor graft function, or grade III-IV aGvHD were significantly associated with adverse outcomes. All HID patients received MSC co-transplantation with hematopoietic stem cells. However, the infused MSCs were derived from umbilical cord (UC-MSC group; 43 patients) or bone marrow (BM-MSC group; 48 patients) and were administered at different medical centers. We first compared the outcomes between the two groups and detected that the BM-MSC group exhibited lower incidences of grade III-IV aGvHD and cGvHD ( p  < 0.05). This study suggests that co-transplantation of hematopoietic and MSCs significantly reduces the risk and incidence of graft rejection and may effectively improve overall survival in patients with SAA even in the absence of closely related histocompatible donor material., Competing Interests: Conflict of interest statement: The authors declare that there is no conflict of interest., (© The Author(s), 2020.)

Human leukocyte antigen (HLA) mismatches are targets of alloreactive T cells, mediators of graft-versus-leukemia (GvL) and graft-versus-host disease (GvHD) after alternative donor transplantation. Exploitation of HLA mismatching in order to reduce relapse is hampered by necessary interventions aimed at controlling GvHD on the one hand, and by the possibility of immune escape through selective loss of mismatched HLA in relapsing leukemia on the other. Retrospective studies reporting the impact of HLA mismatches on post-transplant relapse need to be interpreted with caution, due to many confounding factors, including disease and use of T-cell depletion, and to be constantly updated to the rapidly changing clinical protocols. Current evidence suggests similar relapse rates for 8/8, 7/8 HLA-matched unrelated, T-cell-replete haploidentical and umbilical cord blood transplantation; however, investigations of locus-specific effects are still scarce in the latter two settings. In unrelated transplantation, a specific role for mismatches at HLA-C and HLA-DPB1, and therein of permissive mismatches defined on the basis of T-cell alloreactivity and/or expression levels, in reducing relapse has been demonstrated in independent studies. This observation suggests new approaches to utilize HLA matching in unrelated donor searches, and the need for further research in the field., (Copyright © 2016 Elsevier Inc. All rights reserved.)