Peripheral Blood Hematopoietic Stem Cell Research Articles

Analysis of Factors Affecting Hematopoietic Stem Cell Mobilization Efficiency and Early Hematopoietic Reconstruction Indicators during Autologous Peripheral Blood Hematopoietic Stem Cell Transplantation.

Purpose To analyze the factors affecting the mobilization efficiency of hematopoietic stem cells and hematopoietic reconstruction indicators during autologous peripheral hematopoietic stem cell transplantation. Methods The clinical data of 54 patients who underwent autologous peripheral blood hematopoietic stem cell mobilization and transplantation at Xuzhou Central Hospital from May 2016 to April 2023 were retrospectively analyzed. The gender, age, disease type, mobilization regimen, number of chemotherapy sessions, G-CSF (granulocyte colony-stimulating factor) dosage, and platelet number at the time of collection were also collected. Moreover, the relationship between these indicators with mobilization results and hematopoietic reconstruction was analyzed. Results Results showed that age, disease type, and number of collections were significantly related to the mobilization results (number of CD34+ hematopoietic stem cells). Furthermore, multivariate analysis showed that the number of collections was an independent factor affecting mobilization efficiency. Similarly, age, platelet value at the time of collection, CD34+ stem cell value during collection, white blood cell count, and number of chemotherapy times were significantly related to the time of megakaryocytic hematopoietic reconstruction. Multifactor analysis found that age and platelet count were independent factors affecting the reconstruction time of the megakaryocytic system. However, no factor was related to the time of granulocyte hematopoietic reconstruction. Conclusion Platelet count and age when collecting hematopoietic stem cells are closely related to megakaryocytic hematopoietic reconstruction and are key indicators of early hematopoietic reconstruction after autologous hematopoietic stem cell transplantation.

Case report: Difficult diagnosis of Mycobacterium tuberculosis infection in patients after allogeneic hematopoietic stem cell transplantation: two case reports and a literature review

BackgroundMycobacterium tuberculosis (MTB) is a relatively infrequent infection encountered during hematopoietic stem-cell transplantation (HSCT). The identification of MTB following HSCT remains a complex task, with delayed detection and misdiagnosis potentially resulting in unfavorable outcomes. Metagenomic next-generation sequencing (mNGS) represents a novel, highly sensitive, and rapid diagnostic tool in clinical settings for discerning intricate infections and detecting exceedingly rare pathogensMethodsWith the aid of mNGS, we diagnosed MTB in the lymph nodes and lungs of two patients with hematological diseases following allogeneic peripheral blood hematopoietic stem cell transplantation. Both patients presented with a fever, localized symptoms, and clinical signs. Following inconclusive results from routine tests, impractical biopsy procedures, and unsuccessful responses to empirical treatments, mNGS was employed as a final recourse, revealing DNA fragments of MTB in blood samples.ResultsThe diagnoses were ultimately confirmed in conjunction with additional clinical evidence. The application of mNGS in MTB cases after allogeneic HSCT has rarely been reported. The mNGS technique can provide a prompt and highly sensitive indication leading to the definitive diagnosis of MTB in complex post-transplant scenarios.

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.

Against all odds: The road to success in the development of human immune reconstitution mice.

The mouse genome has a high degree of homology with the human genome, and its physiological, biochemical, and developmental regulation mechanisms are similar to those of humans; therefore, mice are widely used as experimental animals. However, it is undeniable that interspecies differences between humans and mice can lead to experimental errors. The differences in the immune system have become an important factor limiting current immunological research. The application of immunodeficient mice provides a possible solution to these problems. By transplanting human immune cells or tissues, such as peripheral blood mononuclear cells or hematopoietic stem cells, into immunodeficient mice, a human immune system can be reconstituted in the mouse body, and the engrafted immune cells can elicit human-specific immune responses. Researchers have been actively exploring the development and differentiation conditions of host recipient animals and grafts in order to achieve better immune reconstitution. Through genetic engineering methods, immunodeficient mice can be further modified to provide a favorable developmental and differentiation microenvironment for the grafts. From initially only being able to reconstruct single T lymphocyte lineages, it is now possible to reconstruct lymphoid and myeloid cells, providing important research tools for immunology-related studies. In this review, we compare the differences in immune systems of humans and mice, describe the development history of human immune reconstitution from the perspectives of immunodeficient mice and grafts, and discuss the latest advances in enhancing the efficiency of human immune cell reconstitution, aiming to provide important references for immunological related researches.

Abstract 2831: Development and application of the NCG-hIL2 mouse model: A humanized platform for enhanced NK cell evaluation in ADCC efficacy testing

Abstract Natural Killer (NK) cells play a pivotal role in immune surveillance and antitumor responses, making them valuable targets in cancer immunotherapy. The assessment of therapeutic antibodies' efficacy, particularly in the context of Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC), necessitates models that faithfully recapitulate human NK cell responses. Here, we introduce the NCG-hIL2 mouse model, designed to address these requirements and advance our understanding of NK cell development. The NCG-hIL2 mouse model was engineered to express human Interleukin-2 (IL2) cytokine, a critical factor in NK cell development and activation. This humanized platform allows for the robust reconstitution of human NK cells through the transplantation of peripheral blood mononuclear cells (PBMCs) or hematopoietic stem cells (HSCs). In this study, we validate the NCG-hIL2 model's exceptional capability in supporting the reconstitution of human NK cells, highlighting the indispensable role of IL2 in NK cell development. Moreover, we demonstrate its utility in the evaluation of therapeutic antibodies, specifically Trastuzumab and the ADCC-enhanced Margetuximab, in the context of ADCC efficacy testing. Our findings reveal that the NCG-hIL2 model provides a unique advantage for assessing the impact of IL2 on NK cell development, thus facilitating a deeper understanding of the complex interplay between NK cells and therapeutic antibodies. The NCG-hIL2 mouse model serves as a valuable tool for studying NK cell development and evaluating the efficacy of immunotherapies, particularly in ADCC. By reconstituting human NK cells and leveraging the role of IL2, this model offers an enhanced platform for preclinical evaluation of therapeutic antibodies, ultimately advancing our ability to harness NK cell-mediated antitumor responses. It is poised to contribute significantly to the field of cancer immunotherapy and drug development. Citation Format: Yuan Fang, Hongyan Sun, Huiyi Wang, Jun Xing, Jialu Fan, Jing Zhao, Xiang Gao, Cunxiang Ju. Development and application of the NCG-hIL2 mouse model: A humanized platform for enhanced NK cell evaluation in ADCC efficacy testing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2831.

The Effects of Busulfan on Xenogeneic Transplantation of Human Peripheral Blood Mononuclear Cells in Recipient Mice

Background. Humanized mouse models with engraftment of human peripheral blood mononuclear cells (PBMCs) or hematopoietic stem cells (HSCs) are effective tools for the study of human immunity. Busulfan has been used as a substitute for irradiation in human hematopoietic stem cell (HSC) transplantation models, but it has not been tested in human peripheral blood mononuclear cell (PBMC) transplantation models.Materials and Methods. This study evaluated PBMC engraftment using cytometry and enzyme-linked immunosorbent assay (ELISA) in female NOD.CB17/Prkdcscid/JKrb/ IL2 receptor γ−/− (NIG) mice treated with busulfan.Results. In this model, the percentage of human CD3+ T cell engraftment in the blood was 28.2%, with dominant infiltration of CD8+ cells in the spleen 3 weeks post PBMC transplantation. Production of human cytokines, including IL-12p70, IL-4, IL-5, IFN-γ, IL-6, IL-8, IL-22, TNF-α, and IL-10, was determined in mice treated with busulfan.Conclusions. Our findings demonstrate that busulfan treatment is a beneficial alternative for simple and efficient PBMC engraftment in a rodent model, possibly helping to evaluate human immunity in preclinical studies.

Galectin-9 alleviates acute graft-versus-host disease after haplo-hematopoietic stem cell transplantation by regulating regulatory T cell/effector T cell imbalance.

Acute graft-versus-host disease (aGVHD) arises from the imbalance of host T cells. Galectin-9 negatively regulates CD4 effector T cell (Th1 and Th17) function by binding to Tim-3. However, the relationship between Galectin-9/Tim-3 and CD4+ T subsets in patients with aGVHD after Haplo-HSCT (haploidentical peripheral blood hematopoietic stem cell transplantation) has not been fully elucidated. Here, we investigated the role of Galectin-9 and CD4+ T subsets in aGVHD after haplo-HSCT. Forty-two patients underwent Haplo-HSCT (26 without aGVHD and 16 with aGVHD), and 20 healthy controls were included. The concentrations of Galectin-9, interferon-gamma (IFN-γ), interleukin (IL)-4, transforming growth factor (TGF)-β, and IL-17 in the serum and culture supernatant were measured using enzyme-linked immunosorbent assay or cytometric bead array. The expression levels of Galectin-9, PI3K, p-PI3K, and p-mTOR protein were detected by western blot analysis. Flow cytometry was used to analyze the proportions of CD4+ T cell subsets. Bioinformatics analysis was performed. In patients with aGVHD, regulatory T (Treg) cells and Galectin-9 decreased, and the Th1, Th17, and Treg cells were significantly imbalanced. Moreover, Treg and Galectin-9 were rapidly reconstituted in the early stage of patients without aGVHD after Haplo-HSCT, but Th17 cells were reconstituted slowly. Furthermore, Tim-3 upregulation on Th17 and Th1 cells was associated with excessive activation of the PI3K/AKT pathway in patients with aGVHD. Specifically, in vitro treatment with Galectin-9 reduced IFN-γ and IL-17 production while augmenting TGF-β secretion. Bioinformatics analysis suggested the potential involvement of the PI3K/AKT/mTOR pathway in aGVHD. Mechanistically, exogenous Galectin-9 was found to mitigate aGVHD by restoring the Treg/Teffs (effector T cells) balance and suppressing PI3K. Galectin-9 may ameliorate aGVHD after haplo-HSCT by modulating Treg/Teffs balance and regulating the PI3K/AKT/mTOR pathway. Targeting Galectin-9 may hold potential value for the treatment of aGVHD.

Effect of voxelotor on murine bone marrow and peripheral blood with hematopoietic progenitor cell mobilization for gene therapy of sickle cell disease

In preparation for hematopoietic stem cell mobilization and collection, current ex vivo gene therapy protocols for sickle cell disease require patients to undergo several months of chronic red cell transfusion. For health care equity, alternatives to red cell transfusion should be available. We examined whether treatment with GBT1118, the murine analog of voxelotor, could be a safe and feasible alternative to red cell transfusion. We found that 3 weeks of treatment with GBT1118 increased the percentage of bone marrow hematopoietic stem cells and upon plerixafor mobilization, the percentage of peripheral blood hematopoietic stem cells. Our data suggest that voxelotor should be further explored for its potential safety and utility as preparation for hematopoietic stem cell mobilization and collection.

Hematopoietic progenitor cell count as a potential quantitative marker in apheresis products during allogeneic stem cell transplantation.

The quality and quantity of hematopoietic stem cells in apheresis products are essential to the success of peripheral blood hematopoietic stem cell transplantation (PB-HSCT). While the flow cytometry measurement of CD34+ cells as a golden standard for stem cell count is labor and cost-intensive, hematopoietic progenitor cell number evaluated by XN Sysmex series automated hematology analyzers (XN-HPC) is suggested as a surrogate marker. We evaluated the correlation and consistency of XN-HPC and CD34+ cell count in apheresis samples from both allogeneic donors and autologous patients during PB-HSCT. Good correlation and consistency were observed between XN-HPC and CD34+ cell counts in harvests collected from healthy donors (R = .852) rather than autologous patients (R = .375). Subgroup analysis showed that the correlation was especially poor when autologous patients used plerixafor as an additional mobilizer or were diagnosed with multiple myeloma (MM). In the setting of allogeneic transplantation, the correlation coefficients were even better in samples from non-first-round apheresis (R = .951), with high white blood cell (WBC) counts (R = .941), or having successful engraftment within 2 weeks (R = .895). ROC analysis suggested that an optimal XN-HPC count of 1127 × 106 /L best predicted a sufficient yield of CD34+ stem cells, with diagnostic sensitivity and specificity being 92% and 72%, respectively (AUC = 0.852). XN-HPC is a sufficient quantitative marker for stem cell assessment of harvest yield in allogeneic but not autologous HSCT.

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.

Cryostorage of peripheral blood hematopoietic stem cells in transplantology: current status and prospects

Peripheral blood hematopoietic stem cell (HSC) transplantation is a well-established procedure for the treatment of hematological, cancer and autoimmune diseases. In cancer patients, HSC transplantation allows the use of high-dose cytotoxic drugs in combination with radiation therapy during treatment, which provides a pronounced antitumor effect. The hematological toxicity of such treatment is eliminated by the sequential introduction of stem cells, which contribute to hematopoiesis restoration. Before transplantation, peripheral blood HSCs are subjected to collection and cryopreservation for further storage. An important requirement for cryopreservation is viable HSCs responsible for hematopoietic restoration. The aim of the review was to analyze the literature devoted to the influence of various methods of cryopreservation of human peripheral blood HSCs on the preservation of cell viability after thawing, as well as the development of adverse events in patients. Issues related to the use of various cryoprotectants, as well as methods for storing HSC grafts, are considered. The presented data indicate the need for further study of the effect of cryoprotectants on the human body and the cellular composition of the graft and improvement of protocols for HSC cryopreservation.

Day 100 Natural Killer Cell/CD14+HLA-DRDIM ratio and survival in lymphoma post-autologous peripheral blood hematopoietic stem cell transplantation.

The infusion of autograft Natural Killer Cells (NKC)/CD14+ HLA-DRDIM ratio is a predictor of survival in lymphoma patients undergoing autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT). This study evaluated if the Day 100 NKC/CD14+ HLA-DRDIM ratio still functions as a prognostic immune-biomarker. This was a retrospective, single-institution, cohort analysis including 107 patients in this study that had clinical assessment at Day 100 post-APBHSCT from our prior phase III trial. We evaluated the prognostic ability of the Day 100 NKC/CD14+ HLA-DRDIM ratio to predict overall survival (OS) and progression-free survival (PFS) using Cox regression model for outcome analysis and survival by Kaplan-Meier method. The median follow-up from day 100 was 94.7 months (range 4.83-158.1 months) for the entire cohort. Patients with a Day 100 NKC/CD14+ HLA-DRDIM ratio ≥1.67 experienced better OS and PFS versus those with a Day 100 NKC/CD14+ HLA-DRDIM ratio <1.67: median OS was not reached versus 49.7 months, the 5-year OS rates were 91% (95% CI, 81%-96%) versus 40% (95% CI, 27%-55%), p<.0001, respectively; and median PFS was not reached versus 23.5 months, the 5-year PFS rates were 66% (95% CI, 55%-81%) versus 21% (95% CI, 15%-40%), p<.0001, respectively. Day 100 NKC/CD14+ HLA-DRDIM ratio was an independent predictor for OS and PFS in the multivariate analysis. Day 100 NKC/CD14+ HLA-DRDIM ratio is a prognostic immune-biomarker in lymphoma patients post- APBHSCT.

Chinese expert consensus on the management of patients with hematologic malignancies infected with SARS-CoV-2.

In December 2022, the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became dominant in China due to its high infectivity and lower mortality rate. The risk of critical illness and mortality among patients with hematologic malignancies who contracted SARS-CoV-2 was particularly high. The aim of this study was to draft a consensus to facilitate effective treatments for these patients based on the type and severity of the disease. Following the outbreak of the novel coronavirus in China, a steering committee consisting of experienced hematologists was formed by the Specialized Committee of Oncology and Microecology of the Chinese Anti-Cancer Association. The expert group drafted a consensus on the management and intervention measures for different types of hematologic malignancies based on the clinical characteristics of the Omicron variant of the SARS-CoV-2 infection, along with relevant guidelines and literature. The expert group drafted independent recommendations on several important aspects based on the epidemiology of the Omicron variant in China and the unique vulnerability of patients with hematologic malignancies. These included prophylactic vaccinations for those with hematologic malignancies, the use of plasma from blood donors who recovered from the novel coronavirus infection, the establishment of negative pressure wards, the use of steady-state mobilization of peripheral blood hematopoietic stem cells, the provision of psychological support for patients and medical staff, and a focus on maintaining a healthy intestinal microecology.

Cryopreserved Versus Non-Cryopreserved Peripheral Blood Haematopoietic Stem Cells for Autologous Stem Cell Transplantation in Multiple Myeloma: A Comparative Analysis from the Chronic Malignancies Working Party of EBMT and WBMT

Introduction: Globally, most transplant centres cryopreserve peripheral blood haematopoietic stem cells (PBSC) for use in a subsequent autologous haematopoietic cell transplant (AHCT), utilizing Dimethyl sulfoxide (DMSO) as a cryoprotectant. In contrast, non-vryopreserved PBSC are used in autologous transplants for multiple myeloma (MM) in some countries with more limited resources. We therefor compared standard MM AHCT outcomes between a large transplant centre in Algeria and EBMT registry data. Patients and Methods: This was a retrospective, international, multi-centre, matched-pair analysis between a tertiary transplant center in Algeria and EBMT-affiliated centres in 23 countries. A total of 437 consecutive adult patients undergoing a first MM AHCT in Oran, Algeria, between 2009 and 2020 using non-cryopreserved PBSC. All patients had given informed consent for approved research. PBSC mobilization was performed using G-CSF alone (10µg/kg) for 5 days. Stem cell collection was performed on either the Cobe Spectra or Optia using standard protocols. PBSCs were stored in a 4°C refrigerator immediatly post-collection. PBSC viability was calculated by standard Trypan Blue and flow cytometric techniques. The conditioning regimen was either Melphalan 140 mg/m 2 or 200 mg/m 2. PBSCs were infused 24 hours following Melphalan administration. Patients from Oran were matched to a maximum of 4 patients from an overall cohort of 64,030 patients from 420 EBMT-affiliated centres receiving cryopreserved stem cells over the same time-period. Pair matching was based on the following criteria: (1) patient gender (M,F), (2) MM sub-classification (IgG, IgA, light-chain only), (3) disease status at AHCT (CR, VGPR, PR, relapse/progression), (4) Melphalan conditioning dosage (140 or 200), (5) interval from diagnosis to AHCT, (6) date of AHCT, and (7) age at AHCT. Exact matching was used for the first four variables; propensity score matching was used for the remaining three. Primary endpoints were neutrophil and platelet engraftment as defined by standard EBMT criteria. Secondary endpoints included non-relapse mortality (NRM). The cumulative incidence of neutrophil and platelet engraftment was estimated using the crude cumulative incidence estimator with death was as competing event. The same method was used to estimate NRM as a competing event. Groups were compared using Gray's test. Results: In Oran, 437 MM patients were autografted between 2009 and 2020. Induction regimens (available in 436/437) were heterogeneous (VAD (11.2%), VD (13.3%), CTD (1.4%), VTD (43.1%), VRD (1.4%), VCD (28.0%), TD (0.5%), PAD (0.5%) or others (0.7%)) reflective of local practice. Most patients had one line of induction therapy (n=333 (76.4%); 98 patients (22.5%) had a second line of therapy prior to mobilization. The mean number of collection procedures was two (range (r), 1-3). The average PBSC viability was 95% (r, 93.8-98.5%). Complete matching variable data was available in 405 Oran patients (93%) and 19/405 (4.7%) could not be matched to EBMT patients. These were mostly younger patients (16/19&amp;lt;50 years at AHCT) who received low dose melphalan (17/19 received 140 mg/m 2 melphalan). Of the 386 patients, 357 patients had the required matches of 4 patients from the EBMT database and were used in this analysis. For the patients from Oran, the median dose of PBSCs collected was 3.2x10 6 CD34+ cells/kg (interquartile range (IQR, 2.4-4.5); for EBMT patients (available in 12%), it was 3.7x10 6CD34+ cells/kg (IQR, 2.8-4.9) (p=0.22). Regarding engraftment kinetics, the median times to neutrophil engraftment for the non-cryopreserved and EBMT cryopreserved cohorts were 12 (IQR, 11 to 14) days, and 12 (IQR, 11 to 13) days, respectively (p=0.11). Moreover, no significant difference was evident in the median time to platelet engraftment&amp;gt;20x10 9/L: non-cryopreserved 12 (r, 11 to 14) days and EBMT cryopreserved 12 (r, 11 to 14) (p=0.39) (Figure 1). Non-relapse mortality at day 100 (NRM) rate was 1%(0-2%) in Oran and 1% (1-1%) in EBMT (p=0.4). Conclusion: This large co-operative study between Oran and EBMT found that neutrophil and platelet engraftment rates were similar in the cryopreserved and non-cryopreserved matched cohorts. Moreover, there was no difference in NRM. The use of non-cryopreserved PBSC for MM AHCT in countries with limited resources is more straighforward and less costly.

ABO Incompatibility Haploidentical Peripheral Blood Stem Cell Transplantation Combined with a Single Cord Blood Unit for Severe Aplastic Anemia Patients

Background: For young severe aplastic anemia (SAA) patients without HLA matched donors, haploidentical hematopoietic stem cell transplantation can be used as an alternative selection. The grafts of classic Beijing protocol in China is a combination of bone marrow and peripheral blood stem cell. For patients with major or minor blood type incompatibility, bone marrow stem cells need to undergo red blood cell or plasma removal treatment. There was rare reports about haploidentical peripheral blood stem cell combined with a single unrelated cord blood unit for ABO incompatibility haploidentical stem cell transplantation in SAA patients. Objective: To observe the efficacy of ABO incompatibility haploidentcial peripheral blood hematopoietic stem cell transplantation combined with a single unrelated cord blood unit for SAA patients. Method s : Fifty-five SAA patients underwent stem cell transplantation from August 2018 to February 2022 in the First Affiliated Hospital of Xi'an Jiaotong Univeristy were divided into two groups based on donor-recipient ABO compatibility, the donor-recipient ABO matched group（BM+PB group）using haploidentical bone marrow and peripheral blood stem cell as grafts, and donor-recipient ABO mismatched group（CB+PB group）, using unrelated cord blood and haploidentical peripheral blood stem cell as grafts. The differences of hematopoietic reconstitution, acute and chronic GVHD, CMV and EB virus infection, PFS, and OS between the two groups were compared. Result s : There were 30 cases in CB+PB group and 27 cases in the BM+PB group. Except for differences in donor-recipient ABO compatibility, the other characteristics of the two groups of patients were comparable((P&amp;gt;0.05). One patient in the BM+PB group had primary graft failure, while the rest of the patients were successfully implanted. There were no significant statistical differences in neutrophil,platelet and red blood cells recovery rates, the incidence of acute and chronic GVHD, CMV, EB virus infection, and PTLD between the two groups of patients(P&amp;gt;0.05). There was no significant statistical difference in OS between the two groups of patients(P&amp;gt;0.05)(Figure 1). Conclusion: For SAA patients with donor-recipient ABO incompatibility could use haploidentical peripheral blood cell combined with unrelated cord blood for transplantation which had compared outcome with haploidentcal bone marrow and peripheral blood cell transplantation.

Phase I/II Study of Reduced Dosing of Post-Transplantation Cyclophosphamide (PTCy) after HLA-Identical Peripheral Blood Hematopoietic Stem Cell Transplantation

Introduction Post-transplant cyclophosphamide (PTCy)-based prophylaxis for acute graft versus host disease (aGvHD) has become a standard protocol in HLA haploidentical bone marrow transplantation. Preliminary evidence indicates that compared to the standard dosage (50 mg/kg on days +3 and +4 post-transplantation), a regimen of half the typical cyclophosphamide dosage is both feasible and effective. However, the optimal dosage and timing of PTCy for aGvHD prophylaxis in a HLA identical setting, using peripheral stem cells as the graft, remain unknown. This study aims to investigate the efficacy and safety of a reduced PTCy dosage regimen in patients undergoing peripheral blood stem cell transplants (PBSCT) with HLA indentical donors. Methods This prospective, single-center phase I/II study enrolled patients scheduled for PBSCT with HLA identical donors. The aGVHD prophylaxis regimen comprised PTCy on days +3 and +4, followed by cyclosporine initiation from day 5 post-transplant. In the phase I stage, an initial cohort of five patients received PTCy at a dosage of 50 mg/kg/day on days +3 and +4 (designated as dose level 1, DL1). This was followed by a 3+3 dose de-escalation design with subsequent dose levels as follows: DL2, 50 mg/kg on day +3 and 25 mg/kg on day +4; and DL3, 25 mg/kg on both day +3 and +4. The dose-limiting toxicity for this de-escalation was defined as the occurrence of grade III-IV aGVHD within the first 100 days post-transplantation. The phase II stage comprised an expansion cohort, which was based on the optimal dose identified during phase I. aGvHD classification was established using the Mount Sinai Acute GVHD International Consortium (MAGIC) criteria, while chronic GvHD (cGvHD) was assessed per the latest National Institutes of Health Consensus on cGvHD. Patients were closely followed-up at +1, +2, +3, +4, +6, +9, +12, +18, and +24 months post-transplant. Results In the first stage, a total of 11 patients (5 in DL1, 3 in DL2, and 3 in DL3) were included, and no patient developed grade III-IV aGVHD. Based on this, DL3 was selected as the PTCy dose for phase II, which comprised 18 patients. Overall, 29 patients (17 females, 12 males) with a median age of 39 years (range 17-65) were included, and the median follow-up duration was 12.7 months (range 2.2-22.1). Patient and disease characteristics are summarized in Table 1. By day +30 post-ASCT, all patients achieved complete remission (CR) and minimal residual disease (MRD) clearance. No patient developed grade III-IV aGVHD within 100 days post-transplantation. There was no significant difference in the neutrophil and platelet engraftment interval among the three groups (Figure 1A, B). Among the 21 patients who received the DL3 dose of PTCy, the estimated cumulative incidence of grade II to IV aGVHD at day +100 was recorded at 28.6%, and the incidence of aGVHD at day +100 presented no difference among the three DL groups (Figure 1C). In addition, 1 patient in DL3 developed grade IV intestinal aGVHD on day +141 and died one month later. The estimated 1-year cumulative incidence of hemorrhagic cystitis (HC) and cytomegalovirus (CMV) reactivation was 19.3% and 19%, respectively (Figure 1D). Five patients (all in DL3) experienced relapse, with a median interval of 6.7 months and an estimated 1-year cumulative incidence of 10.6%. A total of 5 fatalities occurred during our study (1 in DL1, and 4 in DL3), 1 due to relapse, 2 from COVID-19-associated pulmonary aspergillosis, 1 from severe septicemia and 1 due to grade IV aGVHD as mentioned above. The estimated 6-month cumulative incidence of NRM was 9.5%, presenting no difference among the three DL groups (Figure 1E). Among the 20 evaluable patients, the estimated 1-year cumulative incidence of chronic GVHD (cGVHD) and moderate cGVHD was 37.3% and 16% (Figure 1F), respectively, with no severe cGVHD observed. No cases of patient relapse were reported. The estimated 1-year progression-free survival (PFS) and overall survival (OS) were 61.2% and 80.4%, respectively (Figure 1G). Conclusion The findings of this study substantiate that a two-day regimen of PTCy at 25 mg/kg/day serves as an effective and safe prophylactic measure against aGVHD, comparable to the standard dosing protocol. However, to definitively establish whether the de-escalated PTCy dosage provides superior outcomes to the standard regimen, longer-term follow-up and comparative studies are warranted.

Day 100 Inhibitory KIR2DL2 and Activating NKp30 Natural Killer Cell Receptors Predicts Survival Post-Autologous Stem Cell Transplantation in Lymphomas

Introduction: Our group previously published that the infusion autograft inhibitor KIR2DL2 (CD158b+CD337-) and activating NKp30 (CD158b- CD337+) Natural killer (NK) cells receptors were predictors of clinical outcomes in lymphoma patients undergoing autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT) (Porrata et al. Leukemia Research 2019; 81: 1-9). To assess if these subsets of NK cells still hold clinical relevance, we set up to investigate their prognostic ability to predict clinical outcomes at Day 100 post-APBHSCT. Methods: 107 lymphoma patients who participated in our double-blind phase III trail (Porrata et al, Biology of Blood and Marrow Transplantation 2016; 22(6); 1017-1023) and had clinical assessment at Day 100 post-APBHSCT were included in this study. Nkp30 and KIR2DL2 at Day 100 were assessed by flow cytometry analysis. Results: With a median follow-up for the entire cohort from Day 100 was 94.7 months (range: 4.83-158.1 months). Figure 1 shows the overall survival (OS) and progression-free survival (PFS) based on the absolute numbers of KIR2DL2 and Nkp30 NK cells. At Day 100, patients with a KIR2DL2 &amp;lt; 0.08 and Nkp30 ≥0.19 experienced superior OS and PFS compared with patients with a Day 100 KIR2DLD2 ≥0.08 and NKp30 &amp;lt; 0.19. In the multivariate analysis both the KIR2DL2 [OS: HR = 1.767, 95%CI, 1.302-30.31, p &amp;lt; 0.04; and PFS: HR = 2.663, 95%CI, 1.108-6.403, p &amp;lt; 0.03] and Nkp30 [OS: HR = 2.594, 95% CI, 1.239-5.432, p &amp;lt; 0.01; and PFS: HR = 3.676, 95% CI, 1.875-7.206, p &amp;lt; 0.01] were independent predictors for OS and PFS. Conclusion: Day 100 inhibitory KIR2DL2 and activating NKp30 NK cells are prognostic immune-biomarkers in lymphoma patients undergoing APBHSCT.

Predictive Modeling of Hematopoietic Stem Cell Mobilization and Collection Based on Peripheral Blood Marker

Background: Autologous stem cell transplantation (ASCT) is the major transplantation therapy for patients with lymphoma and MM, and the success of auto-HSCT depends on the mobilization efficiency of peripheral blood HSC. In clinical practice, CD34 + cell count in peripheral blood is often monitored to predict the collection effect and determine the collection time. However, prediction of poor mobilizers is still difficult . Methods: We retrospectively analyzed 108 patients with lymphoma and multiple myeloma(MM) at Chongqing University Cancer Hospital who underwent autologous hematopoietic stem cell (HSC) collection between January 2021 to August 2022. There are two groups: collection success group and collection failure group. Compared the differences of clinical characteristics and impact of peripheral blood related detection indexes before autologous HSC collection. Logistic regression analysis was used to establish a prediction model for the successful collection by multi-marker and further evaluated multi-marker prediction models. Results : There was no significant difference in sex, disease type, disease stage, age, disease status before mobilization, mobilization drugs and chemotherapy courses between the successful collection group and the failed collection group ( P&amp;gt; 0.05). The proportion of patients with mobilization days less than 5 days was higher in the successful collection group ( P&amp;lt; 0.05). The platelet count (PLT), mononuclear cell count (MNC) and absolute CD34 + cell count in the successful collection group were significantly higher than those in the failure group. The sensitivity, specificity and area under the curve (AUC) of combining three indexes were 80.9%, 95.9% and 0.944, respectively. Applied the Logistic regression models to the absolute count of PLT, MNC and CD34 + cells to construct the multi-marker prediction algorithms. The 3-marker model of PLT+MNC+CD34 + cells had the lowest AIC, BIC and high AUC. A prediction model was established based on the absolute count of PLT, MNC and CD34 + cells. Conclusion :Patients with less than 5 days of mobilization have a higher success rate of collection. PLT, MNC and CD34 + cell counts before collection can reflect HSC mobilization in patients with lymphoma and MM, and the combination of the three can improve the accuracy of prediction of collection effect.The predictive model based on the absolute number of PLT, MNC and CD34 + cells have good predictive value. Our study suggests that multi-markers are important diagnostic tools for predicting successful collection.

The Effect of Iron Overload on the Mobilization of Peripheral Blood Hematopoietic Stem Cells in Pediatric Patients with Thalassemia Major

Introduction: The purpose of this study was to examine the effect of iron overload on the mobilization of peripheral blood stem cells (PBSCs) in pediatric patients with β-thalassemia major (TM). Methods: We retrospectively reviewed the records of 226 patients with TM from whom PBSCs were collected. Iron overload was based on serum ferritin level, and liver and cardiac iron overload was measured by magnetic resonance imaging (MRI) T2*. Results: The mean age of the TM patients was 7.35 ± 3.41 years. Of the patients, only 171 received MRI. Of the 171 patients, 35 had normal liver iron levels, 39 mild liver iron overload, 90 intermediate liver iron overload, and 7 severe liver iron overload. The intermediate + severe group was associated with significantly higher age and BMI and lower leukapheresis product white blood cell count and CD34⁺ cell levels (all, p < 0.05). Conclusion: Leukapheresis indices were similar between patients with different degrees of iron overload according to the ferritin level and cardiac iron overload, in which the later might be due to the small number of patients with cardiac overload. In patients with TM, the intermediate and severe liver iron overload was associated with poorer mobilization of PBSCs.

Analysis of single-cell sequencing results of an elderly patient with myeloid leukemia reveals high expression of multiple oncogenes in monocytes and hematopoietic stem cells

ABSTRACTObjectiveOlder patients with acute myeloid leukemia (AML) face a higher risk of death. This study analyzed the gene sequencing results of an elderly AML patient to provide new ideas for treatment.MethodsThis study performed single-cell RNA sequencing (scRNA-seq) bioinformatics analysis of blood cells in the peripheral blood and bone marrow of a 64-year-old AML-M5 patient before chemotherapy. The differentially expressed genes (DEGs) were identified, and functional enrichment analyses were performed.ResultsA total of 7990 and 123 DEGs were identified in monocytes and hematopoietic stem cells (HSCs), respectively. Among the top 40 DEGs analyzed, MYB showed high expression in peripheral blood monocytes, while 13 other tumor-related genes exhibited high expression in monocytes in the bone marrow. Peripheral blood and bone marrow HSCs had 6 and 12 highly expressed tumor-related genes respectively, including MCL1, JUN, and JUNB. These genes may form a interconnected network contributing to the progression and heterogeneity of AML, which can have an impact on patient treatment and prognosis.ConclusionsIn conclusion, when treating elderly AML patients, it is important to consider their individual characteristics in order to optimize treatment strategies.