Allogeneic Peripheral Blood Research Articles

Comparison of Outcomes of Haploidentical Peripheral Blood Stem Cell Transplantation with Post-Transplant Cyclophosphamide in Older Versus Younger Patients.

Previous studies have shown that allogeneic peripheral blood stem cell transplantation (PBSCT) from an HLA haploidentical (haplo) donor followed by graft-versus-host disease (GVHD) prophylaxis with post-transplant cyclophosphamide (PTCy) results in lower relapse rates and improved DFS when compared to haplo bone marrow transplant (BMT) with PTCy. However, PBSCT leads to higher rates of GVHD. It is unknown whether the benefits of haplo PBSCT may be nullified in older patients (>60 years) by a higher susceptibility to GVHD and transplant related toxicity. Thus, we sought to determine if older patients receiving haplo PBSCT with PTCy experience significantly worse outcomes than younger patients. We evaluated 121 adult patients with hematologic malignancies treated at the Moffitt Cancer Center with allogeneic haplo PBSCT followed by PTCy and compared outcomes of patients ≥60 years (n = 55) versus patients <60 years (n = 66). The cumulative incidence of non-relapse mortality (NRM) from the competing risk regression analysis was worse for the older patient group (SHR = 4.05, 95% CI: 1.43-11.47, p = 0.008). However, there was no significant difference between groups in graft-versus-host disease (GVHD), relapse, disease-free survival (DFS), or overall survival (OS). Instead, hematopoietic comorbidity index (HCT-CI) ≥ 3 was associated with worse DFS (HR = 1.87, 95% CI: 1.04-3.34, p = 0.035) and OS (HR = 1.98, 95% CI: 1.03-3.84, p-value = 0.042). Subgroup analysis of patients ≥60 years showed a trend toward improved 2-year OS with fludarabine/cyclophosphamide/total body irradiation (Flu/Cy/TBI) versus fludarabine/busulfan: 71% versus 53% (HR = 0.47, p = 0.121). In patients over 70 years (n = 14), NRM was 8% and OS was 76% at 1 year. Given similar OS and DFS between patients aged >60 years and those <60, haplo PBSCT with PTCy appears to be an appropriate transplant platform for older patients.

Optimal timing and impact of allogeneic peripheral blood stem cell transplantation in adult T-cell lymphoblastic lymphoma: insights from a large cohort multi-center real-world study in Shanghai.

In this real-world study, 153 adult T-cell lymphoblastic lymphoma (T-LBL) patients from sixteen centers in Shanghai were enrolled. Out of them, 103 (67.3%) achieved complete remission (CR). The 2-year overall survival (OS) and progression-free survival (PFS) were 56.3% and 47.6%, respectively. In multivariate analysis, CR after induction treatment significantly improved the OS (p = 0.002) and PFS (p = 0.001). Among CR patients, allogeneic peripheral blood stem cell transplantation (allo-PBSCT) significantly lowered the cumulative incidence of relapse (CIR) compared to autologous PBSCT (p = 0.043) and non-SCT (p = 0.001). Among patients undergoing allo-PBSCT in CR, early (within four induction courses) and late CR (after four induction courses) didn't impact the prognosis with similar 2-year OS (p = 0.590), PFS (p = 0.858), CIR (p = 0.50), and non-relapse mortality (NRM) (p = 0.110). Early and deferred allo-PBSCT for early CR patients also yielded similar 2-year OS (p = 0.640), PFS (p = 0.970), CIR (p = 0.994), and NRM (p = 0.974). As a time-dependent covariate, allo-PBSCT presented a positive effect on PFS (p = 0.018) and had a trend toward better OS (p = 0.064). These data suggested that allo-PBSCT should be considered for T-LBL patients upon achieving CR to enhance survival and reduce relapse risk.

Mesenchymal Stem Cells Derived from Human Urine-Derived iPSCs Exhibit Low Immunogenicity and Reduced Immunomodulatory Profile.

Human-induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (iMSCs) represent a promising and renewable cell source for therapeutic applications. A systematic evaluation of the immunological properties and engraftment potential of iMSCs generated from urine-derived iPSCs is lacking, which has impeded their broader application. In this study, we differentiated urine-derived iPSCs into iMSCs and assessed their fundamental MSC characteristics, immunogenicity, immunomodulatory capacity and in vivo engraftment. Compared to umbilical cord-derived MSCs (UCMSCs), iMSCs demonstrated an enhanced proliferative capacity, a higher level of regenerative gene expression, and lower immunogenicity, strengthening resistance to apoptosis induced by allogeneic peripheral blood mononuclear cells (PBMCs) and the NK-92 cell line. In addition, iMSCs exhibited a diminished ability to inhibit T cell proliferation and activation compared with UCMSCs. Transcriptomic analyses further revealed the decreased expression of immune regulatory factors in iMSCs. After transfusion into mouse models, iMSCs engrafted in the lungs, liver, and spleen and exhibited the ability to migrate to tumor tissues. Our results indicated that iMSCs generated from urine-derived iPSCs have a significant replicative capacity, low immunogenicity and unique immunomodulatory properties, and hence offer obvious advantages in immune privilege and allogenic therapeutic application prospects.

Quality Assessment of Cryopreserved Peripheral Blood Stem Cell Products: Evaluation of Two Methods for Flow Cytometric Viability Testing.

The standard flow cytometry method for viability testing using 7-aminoactinomycin D (7-AAD) determines cells in necrosis and late apoptosis. The colony-forming unit (CFU) assay, which evaluates the proliferation ability of HSCs, is also used in graft quality assessment despite known deficiencies that make this assay impractical in routine clinical settings. The aim was to compare the effectiveness of the flow cytometry 7-AAD/annexin V method with the 7-AAD method in assessing the quality of HSCs in autologous and allogeneic peripheral blood stem cell (PBSC) products. Thirty autologous and 30 allogeneic fresh and thawed cryopreserved PBSC products were included in this study. The viability of HSCs was determined using the 7-AAD method and 7-AAD/annexin V method on a flow cytometer, while their clonogenic capacity was assessed by CFU assay. There was an excellent correlation for CD34+ cell viability between the 7-AAD and the 7-AAD/annexin V method for fresh samples (Rs = 0.930, p < 0.001) and a good correlation for thawed PBSC samples (Rs = 0.739, p < 0.001). Excellent correlation was observed for post-thaw CD34+ cell recovery between the two methods for viability (Rs = 0.980, p < 0.001). Statistical analysis showed a weak correlation between CFU-GM recovery and CD34+ cell recovery, regardless of which viability testing method was used (7-AAD method p = 0.021, Rs = 0.298; 7-AAD/annexin V method p = 0.029, Rs = 0.282). Results of this study showed that in the quality assessment of cryopreserved PBSC product viability, the 7-AAD/annexin V method had no added value compared to the 7-AAD method, which was suitable enough for routine quality control of cryopreserved autologous and allogeneic PBSC samples.

Azacitidine combined with interferon-α for pre-emptive treatment of AML/MDS after allogeneic peripheral blood stem cell transplantation: A prospective phase II study.

This prospective clinical study aimed to evaluate the efficacy and safety of the pre-emptive treatment modality of azacitidine in combination with interferon-α (IFN-α) in AML/MDS patients post-transplantation. Forty-seven patients aged 17-62 were enrolled with 14 patients having completed the planned 12 cycles. Following initiation, 72.3% responded positively after the first cycle, peaking at 77.2% by the fifth cycle. Notably, 24 patients maintained sustained responses throughout a median follow-up of 1050 days (range, 866-1234). Overall survival, leukaemia-free survival and event-free survival probabilities at 3 years were 69.5%, 60.4% and 35.7% respectively. Cumulative incidences of relapse and non-relapse mortality were 36.5% and 4.3% respectively. Multivariate analysis identified that receiving pre-emptive treatment for fewer than six cycles and the absence of chronic graft-versus-host disease after intervention was significantly associated with poorer clinical outcomes. The combination of azacitidine with IFN-α was well-tolerated with no observed severe myelotoxicity, and the majority of adverse events were reversible and manageable. In conclusion, the use of azacitidine in conjunction with IFN-α as pre-emptive therapy is a safe and effective treatment to prevent disease progression in AML/MDS patients with MRD positivity post-allo-HSCT.

Complications and the impact of hematological parameters in donors involved in allogenic peripheral blood stem cell transplantation for hematological malignancies

Hematopoietic stem cell transplantation (HSCT) is a vital treatment option for many hematological malignancies, offering a more convenient alternative to bone marrow transplantation. In allogeneic HSCT, donors provide hematopoietic stem cells for transplantation into patients, necessitating careful consideration of the donor's health and hematological parameters to ensure successful engraftment and treatment outcomes. In a study involving 20 adult donors at Apeksha Hospital, Sri Lanka key hematological parameters, comorbidities, clinical histories, and medications were analyzed. Diabetes mellitus and hypertension were the most prevalent comorbidities among donors, while anemia, primarily linked to iron and vitamin B12 deficiencies, was common. Although baseline coagulation abnormalities were rare and no significant complications occurred during transplantation, early clinical issues such as pain and paresthesia correlated with abnormal peripheral blood smear findings. Notably, a 4-day single daily G-CSF dosing schedule was favored over a 5-day twice daily regimen due to fewer reported problems. While anemia and thrombocytopenia were infrequent, these findings underscore the critical importance of meticulous donor selection and vigilant monitoring throughout the transplantation process to optimize outcomes.

Comparable outcomes of allogeneic peripheral blood versus bone marrow hematopoietic stem cell transplantation from a sibling donor for pediatric patients.

Traditionally, bone marrow (BM) has been preferred as a source of stem cells (SCs) in pediatric hematopoietic SC transplantation (HSCT); however, the use of peripheral blood SCs (PBSC) has recently increased. With advancing graft-versus-host disease (GVHD) prophylaxis, whether the BM is still a better SC source than PB in sibling donor HSCT remains controversial. Here, we compared the results of BM transplantation (BMT) and PBSC transplantation (PBSCT) in pediatric patients with malignant or non-malignant diseases receiving sibling HSCT using a total of 7.5mg/kg of anti-thymocyte globulin (ATG). We retrospectively reviewed children who received HSCT from a sibling donor between 2005 and 2020 at Seoul National University Children's Hospital. Of the 86 patients, 40 underwent BMT, and 46 underwent PBSCT. Fifty- six patients had malignant diseases, whereas thirty patients had non-malignant diseases. All conditioning regimens comprised ATG. Busulfan-based myeloablative conditioning regimens were administered to patients with malignant diseases and approximately half of those with non-malignant diseases. The remaining half of the patients with non-malignant diseases were administered cyclophosphamide-based reduced- intensity conditioning regimens. According to studies conducted at our center, all BM donors received G-CSF before harvest to achieve early engraftment. In all 86 patients (47 males and 39 females), the median age at the time of HSCT was 11.4 (range, 0.7 - 24.6) years. The median follow-up period was 57.9 (range, 0.9-228.6) months, and the corresponding values for those with BM and PBSC were 77 (range, 2.4-228.6) months and 48.7 (range, 0.9-213.2) months, respectively. Engraftment failure occurred in one patient with BM and no patient with PBSC. The cumulative incidence of acute GVHD with grades II-IV was higher in PBSC (BM 2.5%, PBSC 26.1%, p = 0.002), but there was no significant difference in those with grades III-IV acute GVHD (BM 0%, PBSC 6.5%, p = 0.3703) and extensive chronic GVHD (BM 2.5%, PBSC 11.6%, p = 0.1004). There were no significant differences in treatment-related mortality (TRM) (BM 14.2%, PBSC 6.8%, p = 0.453), 5-year event-free survival (EFS) (BM 71.5%, PBSC 76.2%, p = 0.874), and overall survival (OS) rates (BM 80.8%, PBSC 80.3%, p = 0.867) between BM and PBSC in the univariate analysis. In the multivariate analysis, which included all factors with p < 0.50 in the univariate analysis, there was no significant prognostic factor for EFS or OS. There was no significant difference in the relapse incidence between BM and PBSC among patients with malignant diseases (BM 14.2%, PBSC 6.8%, p = 0.453). Additionally, there were no significant differences in the TRM, 5-year EFS, and OS rates between malignant and non-malignant diseases nor between the busulfan-based myeloablative regimen and reduced-intensity chemotherapy using cyclophosphamide. In this study, we showed no significant differences in EFS, OS, TRM, and GVHD, except for acute GVHD grades II-IV, between BMT and PBSCT from sibling donors, using ATG (a total of 7.5mg/kg). Therefore, PB collection, which is less invasive for donors and less labor-intensive for doctors, could also be considered an acceptable SC source for sibling donor HSCT in children.

Pyogenic spondylitis after Corynebacterium striatum blood stream infection following allogeneic hematopoietic stem cell transplantation for malignant lymphoma

Patient 1 was a 70-year-old woman with refractory diffuse large B-cell lymphoma who received allogeneic peripheral blood stem cell transplantation from an HLA-haploidentical related donor. Upper back pain appeared on day63, and Th8-Th9 pyogenic spondylitis was diagnosed based on magnetic resonance imaging (MRI). Blood culture on day14 identified Corynebacterium striatum as the causative bacteria of blood stream infection (BSI). The pyogenic spondylitis resolved after treatment with daptomycin for 2 months. Patient 2 was a 65-year-old man with relapsed angioimmunoblastic T-cell lymphoma who received bone marrow transplantation from an HLA-DR single-antigen-mismatched unrelated donor. Lower back pain appeared on day30, and L4-L5 pyogenic spondylitis was diagnosed based on MRI. Blood culture was negative. Daptomycin and clindamycin were selected for treatment based on the drug susceptibility of bacteria that had caused pre-engraftment BSI (Escherichia coli on day3 and Corynebacterium striatum on day9), and the pyogenic spondylitis resolved after 6 months of this treatment. Pyogenic spondylitis should be considered in the differential diagnosis of back pain accompanied by BSI before engraftment in allogeneic hematopoietic stem cell transplant recipients.

Efficacy of Triple Prophylaxis for Prevention of Graft-Versus-Host Disease in Matched Sibling Allogeneic Peripheral Blood Hematopoietic Stem Cell Transplantation in Pediatric Patients

BACKGROUND: Graft-versus-host disease (GVHD) continues to compromise the overall success of allogenic hematopoietic stem cell transplantation. It is the most important cause of morbidity and non-relapse mortality after allogeneic hematopoietic stem cell transplantation for malignant disease. In adults, post-transplant cyclophosphamide (Cy-PT) has been shown to be a feasible, economically accessible, and effective strategy to reduce the incidence of GVHD in matched sibling hematopoietic stem cell transplantation in combination with a calcineurin inhibitor plus mycophenolate mofetil (MMF). AIM: Demonstrate the clinical benefit of Cy-PT plus a calcineurin inhibitor combined with MMF for GVHD prophylaxis in HLA-matched, related peripheral blood stem cell transplants in pediatric patients with malignant hematologic neoplasms compared to standard therapy in historical controls. METHODS: A retrospective study was conducted on 22 pediatric patients with malignant hematologic neoplasms who underwent HLA-matched related peripheral blood allogenic stem cell transplantation (alloSCT) between July 2012 and December 2022. A comparison was made between two groups, one with triple prophylaxis using Cy-PT, cyclosporine (CsA), and MMF, and a historical cohort that received standard GVHD prophylaxis based on CsA and methotrexate (MTX). Patients were identified from a hospital registry. Descriptive and inferential statistics will be reported, using SPSS version 25 for analysis. RESULTS: Twenty-two patients received HLA-matched alloSCT from first-degree relatives genotypically identical in HLA-A, HLA-B, and HLA-DRB1 alleles. The demographic characteristics of both groups are summarized in the table. No patient experienced primary graft failure, sinusoidal obstructive syndrome, or hemorrhagic cystitis. Acute GVHD grade II-IV did not develop in patients who received Cy-PT, whereas in the CsA/MTX prophylaxis group, 1 (9%) grade IV patient was observed who died due to this cause before day 100. Two patients (18%) developed Moderate/Severe GVHD in the CsA/MTX group, and 1 (9%) had moderate GVHD in the Cy-PT group. Two-year overall survival was similar between the two groups (Cy-PT 53% and CsA/MTX 67%), as was event-free survival (PTCy 48% vs. CsA/MTX 61%). CONCLUSION: Peripheral blood represents a feasible option in our setting due to rapid graft engraftment, short hospital stays, and low incidence of primary graft failure, but with a higher incidence of GVHD as reported in the literature. We explored the efficacy and safety of triple prophylaxis for HLA-matched alloSCTs from peripheral blood using Cy-PT + CsA + MMF in a small group of patients, with outcomes slightly better than standard prophylaxis. These preliminary results motivate us to continue with this new regimen.

Haploidentical and Matched Sibling Transplantation for Acute Myeloid Leukemia: A Hospital-Based Study.

Allogeneic peripheral blood stem cell transplantation (PBSCT) has been increasing for the last years in Latin America. The objective of this study was to describe clinical outcomes in acute myeloid leukemia (AML) receiving allogeneic PBSCT between 2013 and 2019 in a single center of Cali, Colombia. A retrospective cohort study was conducted in Fundacion Valle del Lili. Patients diagnosed with AML who received an allogeneic PBSCT between 2013 and 2019 using human leukocyte antigen (HLA)-matched sibling donors (MSDs) or haploidentical related donors (HRDs) with myeloablative conditioning regimen were included. Cases with diagnosis of promyelocytic leukemia, myelodysplastic syndrome-related AML and therapy-related AML were excluded. Data were obtained directly from the hospital PBSCT database and clinical records. A total of 50 patients were included (HRD, n = 32; MSD, n = 18). Sixty-two percent was in the first complete remission (CR1) at the time of the transplant, of which 26% were MSD and 74% were HRD. The European Group for Blood and Marrow Transplantation (EBMT) risk score was: 44% vs. 50% low, 28% vs. 28% intermediate and 28% vs. 22% high for MSD vs. HRD, respectively. Overall survival at 5 years for MSD was 62% (95% confidence interval (CI): 31-83%) and 43% (95% CI: 25-60%) for HRD. Event-free survival was 56% (95% CI: 26-78%) and 35.6% (95% CI: 18-53%), respectively. Non-relapse mortality at day-100 was 6% (95% CI: 0.8-35%) and 20% (95% CI: 9-39%). Relapse at5 years was 18% (95% CI: 4-58%) and 25% (95% CI: 10-52%). Overall mortality rate was 46%. The grade II-IV, III-IV acute graft-versus-host disease and severe chronic graft-versus-host disease was 44%, 11% and 12% for MSD, and 43%, 9% and 0% for HRD. These results underline that MSD remains the first donor choice for AML patients in CR1 when available. HRDs are still our next option among alternative donors. It is necessary to find strategies that have a positive impact on those outcomes that markedly affect the quality of allogeneic PBSCT and the prognosis of patients. Comparative, randomized, prospective studies with longer follow-up of haploidentical allogeneic PBSCT with other donor types are required to definitely establish its role among alternative donors.

Unrevealing Hematopoietic Reconstruction Discrepancies after Allo-UCBT and Allo-PBSCT at Single Cell Resolution

Umbilical cord blood (UCB) and G-CSF mobilizing peripheral blood stem cell (G-PBSC) are the main sources of hematopoietic stem cells for transplantation on clinic. Clinical data have shown that hematopoietic reconstruction in allogeneic cord blood transplantation (allo-UCBT) is significantly delayed compared with allogeneic peripheral blood stem cell transplantation (allo-PBSCT), suggesting that the cellular composition and reconstruction dynamics of UCB are significantly different from that of G-PBSC. Following on the heels of our recently study that found HSC/MPPs show differentiation bias to megakaryocytic-erythroid lineage and strong proliferation tendency, and defined a neutrophil progenitor population named S100A hi Neu2 which is inversely associated with the incidence of GVHD after allo-PBSCT (Yingying Huo et al, Science Immunology 2023), we next aimed to analyze the differences of hematopoietic reconstitution between allo-UCBT and allo-PBSCT and the causes of delayed hematopoietic reconstitution after allo-UCBT. In this study, we collected peripheral blood (PB) and bone marrow (BM) samples from 8 patients with bone marrow failure syndrome (BMFs) who received allo-UCBT (n=4) or allo-PBSCT (n=4) at different time points (d14, d21, d30, d60, d90, d180, d365) after transplantation. At the same time, UCB, G-PBSC and BM of normal children were collected as controls. Lin -CD34 + cells from BM, G-PBSC and UCB were separated by FACS for STRT-seq, the total nucleated cells (TNCs) of all samples were isolated for 10X transcriptome sequencing. We used 276628 hematopoietic cells to map the single cell transcriptome profiles of hematopoietic reconstruction by different transplantation methods and annotated 44 cell types. Compared with the G-PBSC, the immunogenicity of HSC/MPPs in Lin -CD34 + cells derived from UCB decreased, the proportion increased, and the differentiation bias of HSC/MPPs to monocytic and erythroid lineage was stronger, but the differentiation ability to myeloid and megakaryocytic lineage was decreased, the proportion of EBM, MEP and CMP decreased. For TNCs, the proportion of T cells and NK cells increased, and NK_CD56dim_CD16 had a stronger immune function. Compared with allo-PBSCT, the differentiation of HSC/MPPs and CMP into neutrophils in the early stage after allo-UCBT was weakened. The proportion of MEP cells decreased, and the differentiation ability of HSC/MPPs to MEP, HSC/MPPs and MEP to Mk was weakened. In summary, we found that the delayed reconstruction of neutrophils and platelets in patients with allo-UCBT are related to the nature of the graft, suggesting the importance of reasonable intervention of HSC derived from UCB to accelerate platelet implantation.

Higher Infused CD34+ Cell Dose Does Not Influence Clinical Outcomes in Allogeneic Peripheral Blood Stem Cell Transplantation Using Post-Transplant Cyclophosphamide in Children with High-Risk Leukemia

Background: The impact of infused graft cell dose on outcomes, including graft-versus-host disease (GVHD) and relapse, which have been major challenges in allogeneic hematopoietic stem cell transplantation (HSCT), remains unclear. Post-transplant cyclophosphamide (PTCy) has emerged as an effective and safe GVHD prophylaxis strategy, with improved GVHD incidence and relapse-free survival (RFS). Early practice of unmanipulated peripheral blood stem cell transplantation (PBSCT) using PTCy was commonly performed with a restriction on the CD34 + cell dose to minimize the risk of GVHD. However, recent studies demonstrated the protective effect of CD34 + cells on relapse, with no association with GVHD, thereby raising questions about the optimal cell dose. In this context, we aimed to study the impact of infused cell dose on outcomes in children with high-risk leukemia who underwent allogeneic PBSCT using PTCy. Methods: A retrospective analysis was conducted on 50 pediatric patients (median age at diagnosis : 9.3 years, range, 0.3-17.3) with hematologic malignancy (33 acute myeloid leukemia, 12 acute lymphoblastic leukemia, and 4 myelodysplastic syndrome/myeloproliferative neoplasm, 1 other) in first or second remission between 2019 and 2023. They received their first allogeneic PBSCT and donors included matched or mismatched unrelated donors (n=12) and haploidentical family donors (n=38). Conditioning was myeloablative, and PTCy-based GVHD prophylaxis (50mg/kg/day on days 3 and 4) was used for all patients. The patients were divided into three groups based on infused CD34 + cell dose: high dose group (&amp;gt;10 × 10 6/kg, N=10), intermediate dose group (5-10 × 10 6/kg, N=24), and low dose group (&amp;lt;5 × 10 6/kg, N=16). Results: The median age at HSCT was 11.6 years (range, 0.7-24.9). The median dose of infused CD34 + cells and CD3 + cells was 6.5 x 10 6/kg and 48.6 x 10 7/kg, respectively. There was a tendency for the mean dose of infused CD3 + cells to increase in the group with higher infused CD34 + cell dose: 47.6 x 10 7/kg for low dose group, 57.5 x 10 7/kg for intermediate dose group, and 73.4 x 10 7/kg for high dose group ( P=0.053). Patients receiving a higher dose of CD34+ cells had significantly shorter median time to neutrophil engraftment (13 days in high dose group vs. 14 days in intermediate dose group vs. 17 days in low dose group, P&amp;lt;0.001). The time to platelet engraftment was similar among the three groups. There was no difference among high dose, intermediate dose, and low dose groups in the cumulative incidence (CI) of day+100 grades II-IV acute GVHD and moderate to severe chronic GVHD (grades II to IV acute GVHD: 60.0% vs. 63.6% vs. 73.3% [ P=0.988], respectively; moderate to severe chronic GVHD: 22.2% vs. 29.2% vs. 25.0% [ P=0.961], respectively). With a median observation period of 20.4 months (range, 3.0-46.8) from transplant, RFS and overall survival (OS) showed a non-significant trend towards a higher survival rate in the high dose group compared to the other groups (RFS: 76.2% in high dose group vs. 62.1% in intermediate dose group vs. 62.6% in low dose group, P=0.694; OS: 88.9% in high dose group vs. 63.0% in intermediate dose group vs. 76.0% in low dose group, P=0.788). Conclusions: Higher number of infused CD34 + cell dose was associated with faster neutrophil engraftment. For patients in the high dose group (CD34 + cell dose &amp;gt; 10 x 10 6/kg with a relatively higher number of CD3 + cells), a non-significant trend toward a higher survival rate was observed, with no detrimental impact on GVHD. PBSCT in a pediatric patient from an unrelated or haploidentical adult donor may result in a high infused cell dose. Our findings suggest that restricting the number of infused CD34 + cell dose may not be necessary in the setting of allogeneic PBSCT with PTCy. Larger cohort studies are needed to confirm the potential benefits and drawbacks of a higher cell dose in children who receive PBSCT within a PTCy setting.

Haploidentical Donor Transplants with Cytokine Release Syndrome Have Increased Risk of Clinically Significant Early CMV Reactivation Compared with Matched Donor Transplants Receiving Post-Transplant Cyclophosphamide

Background: Post-transplant cyclophosphamide (PTCy) enables safe haploidentical stem cell transplantation by reducing graft-versus-host-disease (GVHD) but is associated with an increased risk of reactivation of Cytomegalovirus (CMV). PTCy has more recently been adopted for matched-donor transplants, where early CMV reactivation may also be more common. This suggests that CMV reactivation is a function of PTCy rather than donor source. However, other studies comparing the rates of CMV in transplants using PTCy-based prophylaxis suggested disparity in donor source may contribute to CMV reactivation. Aim: The goal of this single-centre, retrospective study was to determine if donor type had any impact on CMV reactivation in the setting of PTCy-based GVHD prophylaxis. Methods: The Alfred Hospital Bone Marrow Transplantation Unit has used PTCy for GVHD prophylaxis in both haploidentical and matched-donor allogeneic stem cell transplants (alloSCT) since 2015. A local database search identified 119 allogeneic peripheral blood alloSCT recipients receiving PTCy-based GVHD prophylaxis between February 2015 and December 2022. Matched-donor alloSCTs also received cyclosporin from Day +5 while haploidentical alloSCTs also received tacrolimus and mycophenolate from Day +5. One patient was excluded due to CMV viremia at the time of transplant. Recipients who were CMV seropositive received therapeutic dose valganciclovir 900 mg twice daily from the start of conditioning until the day prior to stem cell infusion. Prophylactic valganciclovir (900 mg daily) was planned upon engraftment for seropositive recipients and those receiving stem cells from a seropositive donor. CMV DNA PCR was performed weekly for the first 100 days post-transplant and beyond when clinically indicated. CMV viremia was defined as any positive CMV PCR (&amp;gt; 34.5 copies/mL) within the first 100 days post-transplant. Therapeutic valganciclovir was initiated for CMV viral loads (VL) &amp;gt; 1,000 copies/mL or earlier for rapidly rising VLs. Cytokine release syndrome (CRS) was defined as fever &amp;gt; 38 degrees Celsius between stem cell infusion and PTCy on Day +3 without an alternate explanation and graded according to CTCAE criteria. CMV donor and recipient negative transplants were excluded from the analysis of the impact of donor disparity on CMV reactivation. Statistical analyses included Fisher's Exact test, one-way ANOVA and Binomial Logistic Regression. Results: Transplant characteristics according to donor source were similar apart from conditioning intensity, where recipients of haploidentical stem cells were more likely to receive myeloablative conditioning (Table 1). The cumulative incidence of moderate-severe chronic GVHD was significantly higher in matched sibling transplants but overall, 12-month GVHD-free and relapse-free survival were similar. As previously reported, CRS (overall and grades II-IV) was significantly more common in haploidentical transplants. Day 100 CMV viremia rates were not statistically different between donor groups. However, haploidentical transplants trended for earlier CMV reactivation (p=0.08), and were significantly more likely to rise above 250 copies/mL (Table 1 and Figure 1). Consequently, haploidentical transplant recipients received significantly more anti-CMV therapy (p=0.009). Multivariable analysis identified haploidentical donor as a major risk factor for CMV &amp;gt; 250 (odds ratio, OR 1.24, p=0.011) and &amp;gt; 1,000 copies/mL (OR 1.41, p=0.032) while transplant for AML/MDS was negatively associated with CMV &amp;gt; 250 (OR 0.19, p=0.009) and CMV &amp;gt; 1,000 copies/mL (OR 0.16, p=0.003). CRS was significantly associated with CMV &amp;gt; 1,000 copies/mL (OR 3.33, p=0.032) but this was no longer significant in multivariable analysis due to the association with haploidentical donor transplantation. Conclusion: This single-center retrospective comparison of PTCy-based transplants shows that haploidentical transplants have increased risk of early and clinically significant reactivation of CMV. Potential explanations include increased immunosuppression with mycophenolate and the presence of CRS, where inflammatory cytokines may de-repress the CMV major immediate early promoter. Selecting this high-risk group (haploidentical transplants with CRS) may be a cost-effective use of letermovir, which can be initiated prior to engraftment.

Azacitidine Combined with Interferon α for Preemptive Treatment of AML/MDS after Allogeneic Peripheral Blood Stem Cell Transplantation：a Prospecitive Phase II Study

Objective : this study investigated the efficacy and safety of azacitidine and interferon α preemptive treatment in the post-transplant in patients with AML/MDS. Methods: between Octorber 1, 2019 and July 31, 2022, a total of 49 patients aged 17 to 62 years were enrolled into this prospective clinical study of post-transplant azacitidine combined with interferon α preemptive treatment. Patients with minimal residual disease (MRD) positive and / or mixed chimerism were scheduled to receive azacitidine, given as 32 mg/m 2 per day subcutaneously for 5 days, and interferon α 3 million units/m 2 per day from 8th day and continued for 28th day for 1 cycle. Results: patients who acquired treatment response were 34 (69.4%), of which turned MRD-negative and obtained complete chimerism were 22 (44.9%) and 5 (10.2%) at 1 cycle, respectively. Median follow-up time after preemptive intervention was 440(range, 45 to 927) days. Cumulative incidences of relapse (CIR) and no relapse mortality (NRM) were 36.7% and 4.1%, respectively. Probabilities of event-free survival (EFS) and overall survival (OS) were 55.1% and 71.4%, respectively. The most common adverse events were graft-versus-host disease (GVHD) (38.8%), liver toxicity (46.9%) and neutropenia (28.6%). Conclusion: these data support the notion that azacitidine combined with interferon α is better used as the preemptive therapy against relapse tendency for patients after allo-HSCT performed for AML/MDS. Side effects were mainly GVHD, reversible cytopenia and hepatic toxicity. This prospective trial in the post-transplant setting was feasible and safe but challenging. This trial was registered at www.clinicaltrials.gov as#NCT04078399.

Immune-privileged tissues formed from immunologically cloaked mouse embryonic stem cells survive long term in allogeneic hosts

The immunogenicity of transplanted allogeneic cells and tissues is a major hurdle to the advancement of cell therapies. Here we show that the overexpression of eight immunomodulatory transgenes (Pdl1, Cd200, Cd47, H2-M3, Fasl, Serpinb9, Ccl21 and Mfge8) in mouse embryonic stem cells (mESCs) is sufficient to immunologically ‘cloak’ the cells as well as tissues derived from them, allowing their survival for months in outbred and allogeneic inbred recipients. Overexpression of the human orthologues of these genes in human ESCs abolished the activation of allogeneic human peripheral blood mononuclear cells and their inflammatory responses. Moreover, by using the previously reported FailSafe transgene system, which transcriptionally links a gene essential for cell division with an inducible and cell-proliferation-dependent kill switch, we generated cloaked tissues from mESCs that served as immune-privileged subcutaneous sites that protected uncloaked allogeneic and xenogeneic cells from rejection in immune-competent hosts. The combination of cloaking and FailSafe technologies may allow for the generation of safe and allogeneically accepted cell lines and off-the-shelf cell products.

Alteration of PBMC transcriptome profile after interaction with multipotent mesenchymal stromal cells under “physiological” hypoxia

Multipotent mesenchymal stromal cells (MSCs) have demonstrated a pronounced immunosuppressive activity, the manifestation of which depends on the microenvironmental factors, including O2 level.Here we examined the effects of MSCs on transcriptomic profile of allogeneic phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMCs) after interaction at ambient (20%) or “physiological” hypoxia (5%) O2. As revealed with microarray analysis, PBMC transcriptome at 20% O2 was more affected, which was manifested as differential expression of more than 300 genes, whereas under 5% O2 220 genes were changed. Most of genes at 20% O2 were downregulated, while at hypoxia most of genes were upregulated. Altered gene patterns were only partly overlapped at different O2 levels. A set of altered genes at hypoxia only was of particular interest. According to Gene Ontology a part of above genes was responsible for adhesion, cell communication, and immune response. At both oxygen concentrations, MSCs demonstrated effective immunosuppression manifested as attenuation of T cell activation and proliferation as well as anti-inflammatory shift of cytokine profile.Thus, MSC-mediated immunosuppression is executed with greater efficacy at a “physiological” hypoxia, since the same result has been achieved through a change in the expression of a fewer genes in target PBMCs.

Low-Dose ATG Has the Same Risk of CMV Reactivation after Allogeneic PBSCT As Ptcy, but Letemovir Is Effective in Preventing CMV Reactivation

[Introduction] Allogeneic peripheral blood stem cell transplantation (allo-PBSCT) is a curative treatment for hematological malignancies but has a risk of a chronic graft-versus-host disease (GVHD) compared to other donor sources. Post-transplant cyclophosphamide (PTCY) has been spread rapidly worldwide from HLA haploidentical-SCT (Haplo-SCT) to HLA matched-SCT. Although PTCY was theoretically thought to preserve non-alloreactive T cells which can contribute to fight infection, recent studies showed that PTCY was associated with the increased incidence of cytomegalovirus (CMV) infection. Letermovir (LTV), a novel anti-CMV agent, was useful for the prevention of CMV reactivation after SCT including Haplo-SCT using PTCY. On the other hand, low-dose antithymocyte globulin (ATG) is an alternative and useful option for GVHD prophylaxis in allo-PBSCT and often used in Japan. However, the risk of post-transplant CMV reactivation and the protective effect of LTV when using low-dose ATG remain to be elucidated. [Methods] We retrospectively analyzed 222 recipients who received allo-PBSCT using PTCY or low-dose ATG at Hokkaido University Hospital from January 2013 to July 2021. Of the 121 patients who underwent PBSCT with PTCY, 69 (all patients underwent Haplo-PBSCT) were without LTV prophylaxis and 52 (34 patients, Haplo-PBSCT) were with LTV. On the other hand, of the 101 patients who underwent PBSCT with low-dose ATG, 66 (12 patients, Haplo-PBSCT) were without LTV and 35 (2 patients, Haplo-PBSCT) were with LTV. LTV was administered on the day 0 at a dosage of 480 mg daily. All patients were monitored for CMV reactivation by using the anti-CMV pp65 monoclonal antibody HRP-C7 assay at least weekly from neutrophil engraftment to discharge and after discharge monthly until day 180 after SCT. CMV reactivation was defined as the start of CMV preemptive therapy, generally initiated when there are 2 or more CMV antigen positive cells per 50000 white blood cells. Moreover, CMV disease was defined by organ dysfunction attributable to CMV. [Results] Baseline characteristics of the patients are summarized in Table 1. Although more patients in ATG group compared to PTCY group received myeloablative conditioning regimen significantly, there was no significant difference between the groups in terms of sex, age, underlying disease, disease risk at SCT, and CMV serostatus. GVHD prophylaxis in PTCY consisted of CY (40-50 mg/kg on day 3 and 4), tacrolimus (from day 5), and mycophenolate mofetil (from day 5), whereas that in ATG consisted of ATG at a total dose of 2-3 mg/kg around day -2, tacrolimus (from day -1) and short-term methotrexate. LTV prophylaxis significantly reduced the cumulative incidence of CMV reactivation at 180 days after SCT in PTCY group (69.6% without LTV vs. 22.4% with LTV, p&amp;lt;0.001) and ATG group (62.6% without LTV vs. 18.9% with LTV, p&amp;lt;0.001; Figure 1.). Importantly, although CMV disease were occurred in 2 patients in PTCY (1 gastritis and 1 retinitis) and 8 focuses in 7 patients (3 pneumoniae, 3 enteritis, 1 retinitis, and 1 glossitis) in ATG without LTV prophylaxis, none of the patients receiving LTV developed CMV disease in both group. Moreover, LTV did not affect overall survival, the cumulative incidence of non-relapse mortality, relapse, acute GVHD, and engraftment of neutrophil and platelet. Interestingly, the cases of early CMV reactivation within 100 days after SCT under LTV prophylaxis was significantly more frequent in ATG than in PTCY (p=0.0345). [Conclusion] CMV reactivation occurred with similar frequency after allo-PBSCT with low-dose ATG as after that with PTCY. LTV was effective for prevention of CMV reactivation in both GVHD prophylaxis methods. CMV breakthrough reactivation may be likely to occur in PBSCT with low-dose ATG compared to that with PTCY even under LTV prophylaxis, and careful CMV monitoring may be required.

Comparison between Post-Transplant Cyclophosphamide Use and Conventional Prophylaxis of Graft-Versus-Host Disease: A Retrospective Study

Introduction: In order to modify the immune response balance between donor and recipient in the context of haploidentical transplantation, the use of post-transplant cyclophosphamide (PTCy), which reduces the population of recipient alloreactive T cells, has become the preferred strategy for graft-versus-host disease (GVHD) prophylaxis. Recently, this approach has also been tested and validated in HLA-matched related or unrelated transplants, as well as in unrelated transplants with HLA mismatch. However, high doses of PTCy can cause cardiac toxicity, hemorrhagic cystitis, and potentially increase the incidence of viral infections. Therefore, comparative studies are needed to evaluate the outcomes of PTCy use compared to other conventional GVHD prophylaxis strategies. Objective: To evaluate the outcomes of patients undergoing allogeneic peripheral blood stem cell transplantation (PBSCT) and to compare the use of post-transplant cyclophosphamide with other GVHD prophylaxis strategies. Patients and Methods: Retrospective analysis of consecutive patients transplanted between March 2014 and March 2023 at two transplant centers. The median follow-up was 24 months (range: 3-116 months). Results: A total of 118 adult patients undergoing PBSCT were included. There were 70 HLA-matched related donors, 28 HLA-matched unrelated donors, and 20 unrelated donors with one HLA mismatch. The median age was 52 years (range: 18 to 80), with a majority being male (51%). The most common diagnoses were acute myeloid leukemia (37%), acute lymphoblastic leukemia (18%), and myelodysplastic syndrome (18%). The disease risk index (DRI) was considered low or intermediate in 53% of cases, high in 31%, and very high in 16%. The majority of patients (76%) had a low risk of transplant-related complications (HCT-CI). Most patients received reduced-intensity conditioning regimens (78%), and the majority (72%) received some sort of T-cell depletion, with 36 (31%) patients receiving PTCy and 49 (41%) receiving ATG. No significant differences were found between the groups (PTCy vs. non-PTCy) in overall survival at 24 months (65% vs. 61%, p = 0.71, respectively), disease-free survival at 24 months (55% vs. 53%, p = 0.76), non-relapse mortality at 24 months (21% vs. 23%, p = 0.84), relapse rate at 24 months (24% vs. 24%, p = 0.61), neutrophil engraftment at 30 days (89% vs. 93%, p = 0.49), and incidence of grade II-IV acute GVHD at 100 days (31% vs. 29%, p = 0.99), grade III-IV acute GVHD at 100 days (6% vs. 12%, p = 0.22), chronic GVHD at 24 months (42% vs. 50%, p = 0.51), and moderate/severe chronic GVHD at 24 months (19% vs. 23%, p = 0.66). There was also no difference in the incidence of infections, including viral infections and cytomegalovirus reactivation. Conclusions: The use of PTCy demonstrated similar clinical outcomes to other GVHD prophylaxis strategies, without an increased risk of infections or mortality. Therefore, PTCy can be considered a viable, safe, and cost-effective option for GVHD prophylaxis in the context of HLA-matched and HLA-mismatched transplants.

A Case of Multiple Eccrine Poromas with a History of Chemotherapy and Allogeneic Peripheral Blood Stem Cell Transplantation

A "poroid cell neoplasm" is a general term used to describe nodular tumors that consist of poroid cells and cuticular cells. Eccrine poroma, the most common type of poroid cell neolplasm, is a tumor continuous with the epidermis and extends into the dermis in a cord-like fashion. This tumor is almost always seen as a single lesion, with cases of multiple eccrine poromas (eccrine poromatosis) being exceedingly rare. In fact, there have only been about 20 reported cases of multiple eccrine poromas worldwide; all of which were associated with some immunosuppressive state. Here we report another case of eccrine poromatosis; this time in a patient who received an allogeneic peripheral blood stem cell transplant for acute lymphocytic leukemia 18 years prior. Our case of eccrine pormatosis is particularly rare that it involved a truncal tumor distribution, whereas the other reported cases were generally isolated to the extremities.

Microtransplantation, an option to explore in hematological malignancies: A review article

Abstract Hematopoietic stem cell transplant remains a valuable option for a variety of hematological malignancies, but it has its limitations given the patient’s old age, availability of donors, and the risk of morbidity and mortality associated with the procedure like graft-versus-host disease. Microtransplantation (MT) is nonengrafting allogeneic cellular therapy performed by infusing human leukocyte antigen-mismatched allogeneic peripheral blood CD34+ stem cells mobilized with granulocyte colony-stimulating factor after chemotherapy or targeted therapy. A state of transient microchimerism without engraftment will exist postinfusion, and the patient will benefit from graft-versus-tumor effect without being at high risk for graft-versus-host disease. A total of 600 patients with a diagnosis of acute myeloid leukemia, Philadelphia positive acute lymphoblastic leukemia, myelodysplastic syndrome, Hodgkin, and non-Hodgkin’s lymphomas were included in the 11 articles in this review. The results show improved overall survival and progression-free survival, which suggest MT as a valid option to be investigated further in prospective controlled studies. The improved outcomes could be explained by combined recipient-versus-tumor and graft-versus-tumor effects as the patient immune system is preserved, natural killer cells anti-leukemic effect within MT infusion and the effects of regulatory T cells. The major toxicity is myelosuppression, while nonhematologic toxicities are rare.