Hemopoietic Stem Cells Research Articles

Dual effects of endogenous formaldehyde on the organism and drugs for its removal.

Endogenous formaldehyde (FA) is produced in the human body via various mechanisms to preserve healthy energy metabolism and safeguard the organism. However, endogenous FA can have several negative effects on the body through epigenetic alterations, including cancer growth promotion; neuronal, hippocampal and endothelial damages; atherosclerosis acceleration; haemopoietic stem cell destruction and haemopoietic cell production reduction. Certain medications with antioxidant effects, such as glutathione, vitamin E, resveratrol, alpha lipoic acid and polyphenols, lessen the detrimental effects of endogenous FA by reducing oxidative stress, directly scavenging endogenous FA or promoting its degradation. This study offers fresh perspectives for managing illnesses associated with endogenous FA exposure.

Pericardial Delivery of SDF-1α Puerarin Hydrogel Promotes HeartRepair and Electrical Coupling.

The stromal-derived factor 1α/chemokine receptor 4 (SDF-1α/CXCR4)axis contributes to myocardial protection after myocardial infarction (MI) by recruiting endogenous stem cells into the ischemic tissue. However, excessive inflammatory macrophages are also recruited simultaneously, aggravating myocardial damage. More seriously, the increased inflammation contributes to abnormal cardiomyocyte electrical coupling, leading to inhomogeneities in ventricular conduction and retarded conduction velocity. It is highly desirable to selectively recruit the stem cells but block the inflammation. In this work, SDF-1α-encapsulated Puerarin (PUE) hydrogel (SDF-1α@PUE) is capable of enhancing endogenous stem cell homing and simultaneously polarizing the recruited monocyte/macrophages into a repairing phenotype. Flow cytometry analysis of the treated heart tissue shows that endogenous bone marrow mesenchymal stem cells, hemopoietic stem cells, and immune cells are recruited while SDF-1α@PUE efficiently polarizes the recruited monocytes/macrophages into the M2 type. These macrophages influence the preservation of connexin 43 (Cx43) expression which modulates intercellular coupling and improves electrical conduction. Furthermore, by taking advantage of the improved "soil", the recruited stem cells mediate an improved cardiac function by preventing deterioration, promoting neovascular architecture, and reducing infarct size. These findings demonstrate a promising therapeutic platform for MI that not only facilitates heart regeneration but also reduces the risk of cardiac arrhythmias.

Problem issues of law enforcement related to the donation of hemopoietic stem cells and other human anatomical materials

Problem issues of law enforcement related to the donation of hemopoietic stem cells and other human anatomical materials

Abstract 19 CD34+ Cell Isolation from Cord Blood: A Novel Option for Faster, More Consistent Outcomes

Abstract Introduction Immunomagnetic isolation of cells has been long established but still suffers from drawbacks when used for hemopoietic stem cells (HSCs) in cord blood. [Kekarainen et al., 2006] Limitations with HSC isolation from cord blood include steep learning curves, time consuming manual labor, and inconsistent outcomes. [de Wynter et al., 1999; Perdomo-Arciniegas and Vernot, 2011] FerroBioTM has developed a semi-automated system for CD34+ cell isolation from unmodified cord blood (Fig 1A) as a means to provide fast, effective, and consistent isolations. Objectives The purpose of this work is to explore process improvements for the FerroBioTM system. Additionally, this work aims to characterize the resulting cell isolates. Methods The cell isolation protocol was evaluated by flow cytometry for cell counts, viability, and purity (total n=195). Protocol modification included incubation time at various steps, magnetic bead dosing, temperatures, and volumes. The ‘percent of cells captured’ was calculated as the difference between starting CD34 and non-captured CD34 cells. Cryopreservation tolerance was evaluated by freeze-thawing cells in a dimethyl sulfoxide-based media and measuring viability via hemocytometry (n=3). Sterility testing on cell isolates was performed via BacT/ALERT iNST & iAST (n=2). Results Incubation time did not have a significant effect on the efficiency of bead-cell binding (Fig 1B). As the FerroBioTM protocol progressed, final cell purity and viability increased and became more consistent (Fig 1C, D). Additionally, over the same phases of process development, final cell recovery increased 4-fold, from 6.5%±5.9% to 28.1%±9.7%. Post-cryopreservation viability was 78.8%±3.3%. Sterility tests were negative for anaerobic and aerobic bacteria. Discussion By establishing that bead-cell incubation duration did not significantly influence outcomes, the incubation time was considerably reduced, bringing the total processing time to ~3hrs. That said, if an overnight incubation is preferable for an operator’s workflow, the data suggests the process could be flexible to meet such needs. Iterations of the process have also resulted in significant improvements to final cell recovery while maintaining high purity and viability. Additional work is being done to further improve recovery. The initial investigation of sterility and cryopreservation was encouraging, and assays for cell functionality are underway. Figure 1. (A) The FerroBioTM hardware, shown with a cartridge in which cell isolation occurs. (B) The proportion of cells that successfully bound magnetic beads as a function of bead-cell incubation time. Final cell (C) purity and (D) viability, shown at different phases of chronological process development. Statistics: GraphPad Prism 9, 1-way ANOVA followed by a Tukey’s HSD. * p < 0.05, **** p < 0.0001. Each data point corresponds to one CBU.

Haunting innate immune memories of COVID-19

In addition to acute hyperinflammatory responses, SARS-CoV-2 infections can have long-term effects on our immune system leading to, for example, post-acute sequelae of COVID-19 (PASC). In this issue of Cell, Cheong etal. show that severe infections via IL-6 induce persistent epigenetic signatures in hemopoietic stem cells and their myeloid progenitors associated with increased inflammatory potential.

Blockade of tumor-derived colony-stimulating factor 1 (CSF1) promotes an immune-permissive tumor microenvironment

The macrophage colony-stimulating factor 1 (CSF1) is a chemokine essential for the survival, proliferation, and differentiation of mononuclear phagocytes from hemopoietic stem cells. In addition to its essential physiological role in normal tissues, the CSF1/CSF1 receptor axis is known to be overexpressed in many tumor types and associated with poor prognosis. High levels of CSF1 within the tumor microenvironment have been shown to recruit and reeducate macrophages to produce factors that promote tumor invasiveness and accelerate metastasis. In this study, we demonstrate, for the first time, that treating established syngeneic murine colon and breast carcinoma tumors with a CSF1R-blocking antibody also promotes the expansion of neoepitope-specific T cells. To assess the role of tumor-derived CSF1 in these model systems, we generated and characterized CSF1 CRISPR-Cas9 knockouts. Eliminating tumor-derived CSF1 results in decreased tumor growth and enhanced immunity against tumor-associated neoepitopes, potentially promoting an immune permissive tumor microenvironment in tumor-bearing mice. The combination of neoepitope vaccine with anti-PDL1 in the MC38 CSF1−/− tumor model significantly decreased tumor growth in vivo. Moreover, anti-CSF1R therapy combined with the adeno-TWIST1 vaccine resulted in tumor control, decreased metastasis, and a synergistic increase in CD8 T cell infiltration in 4T1 mammary tumors. Analysis of the tumor microenvironment demonstrated greater CD8 T cell infiltration and a reduction in tumor-associated macrophages following CSF1R inhibition in both tumor models. Our findings thus add to the therapeutic potential of CSF1 targeting agents by employing combinations with vaccines to modulate anti-neoepitope responses in the tumor microenvironment.

Primary Myelofibrosis in a Young Girl- A Case Report

Myelofibrosis (MF) is a rare disorder that is classified as one of the myeloproliferative disorders. It is a BCR-ABL1- negative myeloproliferative neoplasm characterized by abnormal proliferation of hemopoietic stem cells within the bone marrow, which leads to overproduction of fibrous tissue. Our patient a young girl of 17 year old presented with lump in left upper abdomen, shortness of breath & generalized swelling. The diagnosis was made based on severe anaemia, pancytopenia in peripheral blood film. Bone marrow trephine biopsy from the tibia revealed myelofibrosis. Splenectomy was done in an attempt to reduce the total volume of malignant cells and improve the features of hypersplenism. Myelofibrosis with hypersplenism in a 17- year- old girl is reported rarely. However, when it does, it usually runs rapid and fatal course. J Bangladesh Coll Phys Surg 2023; 41: 239-243

A PREDICTIVE MODEL FOR ULTRA‐HIGH RISK IN PATIENTS WITH NEWLY DIAGNOSED MULTIPLE MYELOMA: A SINGLE‐CENTER STUDY IN CHINA

Introduction: Although novel therapies have significantly improved the prognosis of multiple myeloma (MM) patients, there are still a subgroup of MM patients experienced early relapse or disease progression. To early identify the patients with compromised prognosis in our center, the study aimed to establish a predictive model for ultra-high risk (UHR) in MM. Methods: A study from a tertiary hospital in western China analyzed the patients with newly diagnosed MM (NDMM) receiving bortezomib and/or lenalidomide-included regimens from January 2015 to June 2021. The last follow-up date was December 31, 2022. The patients were randomly divided (2:1) into training and validation cohorts, and the patients with progression-free survival (PFS) less than 12 months were defined as UHR. Univariate and multivariate Cox regression analyses were performed for clinical feature selection. Independent baseline factors were incorporated and scored to develop the predictive model. The UHR group was then defined beyond the optimal cut-off value of total scores. Results: A total of 314 MM patients were enrolled and 102 (32.5%) patients underwent autologous hemopoietic stem cell transplantation (ASCT). The median time of follow-up was 36.6 months. Disease progression and death occurred in 178 (56.7%) and 69 (22.0%) patients. The median PFS (mPFS) was 36.5 months, and the median overall survival (mOS) was not reached. The mPFS of patients stratified into R-ISS III, R2-ISS III, R2-ISS IV, IMWG high-risk and mSMART double/triple hit was 23.8, 25.6, 10.0, 17.2 and 10.5 months, respectively. Among 54 patients at UHR, less than half of them could be identified by the aboved stratification systems. In the training cohort, elevated LDH, hypercalcemia, 1q21 gain/amplification (1q+) and the presence of extramedullary disease (EMD) showed significant association with UHR in NDMM. Referring to the results, the UHR predictive model was developed as 5 points for elevated LDH, 6 points for hypercalcemia, 7 points for 1q+ and 10 points for EMD. Patients with total scores of more than 12 points can be predicated as UHR. This model identified UHR and non-UHR groups with significantly different mPFS (9.8 v.s. 37.5 months, HR = 3.24, 95% CI:2.09-5.03, P < 0.001) and 5-year OS (63.3% vs. 83.8%, HR = 2.92, 95% CI: 1.47-5.81, P = 0.002). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was 0.77, and in the validation cohort, the UHR model kept good discrimination (AUC: 0.79) at the latest follow-up. Conclusions: In this study, elevated LDH, hypercalcemia, 1q+ and EMD were selected and scored to develop the UHR model for NDMM patients. At present, the extension of follow-up time and expansion of sample size in the validation cohort are still ongoing. External validity is also designed to verify the generalizability of the model. The research was funded by: Natural Science Foundation of Sichuan Province, China, Grant/Award Number: 2022NSFSC1299 Keywords: Risk Models, Multiple Myeloma No conflicts of interests pertinent to the abstract.

Abstract A38: Pediatric Germline CSF3R T618I mutation gives insight into disease progression and long-term therapy options of Chronic Neutrophilic Leukemia

Abstract Chronic Neutrophilic Leukemia (CNL) is a rare BCR-ABL negative myeloproliferative neoplasm that affects approximately 1 in a million individuals. The typical age of onset and disease presentation is in elderly patients with a median age of 63 and a range of 9-84. The oncogenic driver of CSF3R, the G-CSF receptor protein, in CNL has been classified over the last decade and has improved therapies for patients with targeted Tyrosine Kinase Inhibitors, such as Ruxolitinib (a potent JAK1/2 inhibitor). Currently, the only curative option is an allogeneic hemopoietic stem cell transplant with typical median overall survival of 2 years. Because of the low occurrence rate of CNL, there have only been 3 germline cases of CSF3R classified in literature. With these patients, they exhibit a lifelong skewing of the myeloid lineage causing gross neutrophilia. Our patient presented at 13 months with leukocytosis and neutrophilia, resulting in genetic testing revealing the diagnosis of the youngest documented case of CNL. A germline CSF3R T618I constitutive activating mutation was documented in our patient and in her father. Her father had documented lifelong leukocytosis of indeterminate origin and it was not until 33 that genetic testing was done, and he was diagnosed with CNL. He underwent an allogeneic stem cell transplant after being admitted with gross hepatosplenomegaly with a WBC of 322, the highest recorded in a germline CNL patient in literature. Our patient presented to clinic with leukocytosis ranging from 45-98 and hepatosplenomegaly. After a bone marrow aspirate and biopsy was taken to determine disease stage and severity, we immediately began Ruxolitinib therapy. We began 20 mg BID dosing based on platelets and monitored response to therapy while conducting targeted RNA-seq for myelodysplastic and myeloid leukemia genes on the bone marrow, which did not detect any secondary mutations. Ruxolitinib dosing was tapered down in a stepwise fashion, until the patient arrived at the current dose of 7.5 mg BID Ruxolitinib, resulting in stable leukocyte counts around 25. As part of monitoring, we are currently conducting 6-month BM procedures and NGS for AML/MDS genes and Ruxolitinib resistance mutations alongside monthly CBCs. Our patient has been on Ruxolitinib for 9 months and has not developed any secondary contributing mutations and remains sensitive to therapy. We continue to monitor our patient’s response to Ruxolitinib to determine if germline predisposition alters the transformative nature of the disease. Within T618I germline CNL cases, we are investigating the difference in phenotype and disease burden that we observe in our patient’s family compared to literature. Based on current cases, it seems that germline CNL does not transform during childhood and adolescence into AML without the influence of a secondary mutation. Retrospective studies into previous cases of CNL to determine if there is a higher frequency of germline origin could pave the way for potential early-stage therapies and detection of CNL prior to transformation. Citation Format: Kevin Zhang, Matthew Rees, Mahsa Khanlari, Laura Rooms, Raul Ribeiro, Marcin Wlodarski. Pediatric Germline CSF3R T618I mutation gives insight into disease progression and long-term therapy options of Chronic Neutrophilic Leukemia [abstract]. In: Proceedings of the AACR Special Conference: Acute Myeloid Leukemia and Myelodysplastic Syndrome; 2023 Jan 23-25; Austin, TX. Philadelphia (PA): AACR; Blood Cancer Discov 2023;4(3_Suppl):Abstract nr A38.

Abstract 123: Molecular mechanisms of RNA and DNA editing in leukemic transformation of hemopoietic stem and progenitor cells

Abstract Dysregulation of inflammatory cytokine responsive APOBEC3 cytosine deaminases has been shown to be a contributing factor in cancer evolution, presenting as gene expression changes and inclusion of distinct C-to-T mutation patterns. However, the context specificity and mechanisms by which APOBEC3 enzymes promote cancer initiation and progression require further elucidation. Lentiviral overexpression of APOBEC3C and an editase deficient APOBEC3C mutant in healthy cord blood, bone marrow and MPN patient hematopoietic stem/progenitor cells (HSPCs) allows us to study the effects of innate immune deaminase dysregulation in the hematopoietic niche. We are focusing on the upregulation of APOBEC3C and adenosine deaminase acting on RNA1 (ADAR1), as we have previously shown them to be contemporaneously upregulated in the high-risk myelofibrosis (MF) stem cell population compared to normal aged bone marrow. We can compare these novel differential gene expression changes, RNA hyper-editing sites, and DNA mutation signatures induced by APOBEC3 mutagenesis to abnormalities seen in both hematopoietic malignancies and solid tumor cancers. Gene set enrichment analysis (GSEA) performed on this dataset has exposed numerous deregulated pathways brought on by exaggerated levels of APOBEC3, including changes in splicing pathways. To further investigate the complex relationship between splicing and deaminase deregulation, we treated myeloproliferative neoplasm patient samples and normal HPSCs with Rebecsinib (also known as 17S-FD-895), a pharmacologically stable, potent, and selective small molecule splicing modulator, which interestingly caused significant downregulation of APOBEC3C. We will continue to investigate these findings as a potential target to correct the dysregulation seen in MPN progression. Consequently, we aim to use these findings to identify predictive biomarkers and druggable targets of leukemic initiation progression. Citation Format: Jane Marie Isquith, Jessica Pham, Thomas Whisenant, Larisa Balaian, Catriona Jamieson. Molecular mechanisms of RNA and DNA editing in leukemic transformation of hemopoietic stem and progenitor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 123.

Abstract 5661: Pre-clinical development of a dopamine receptor 2, PD-1, and CD47 trispecific antibody for the treatment of solid tumors

Abstract Multispecific antibodies can have multiple independent mechanisms of action to achieve better clinical outcomes in cancers with high unmet medical needs. Here we describe the preclinical development of a trispecific antibody (KJ-101) targeting dopamine receptor 2 (DRD2), PD-1, and CD47. DRD2 is a G protein-coupled receptor upregulated in many cancer types where it correlates with decreased patient survival. In pre-clinical studies, DRD2 is associated with cancer cell stemness and tumor growth. Clinical responses were achieved with small molecules targeting DRD2 and dopaminergic drugs for neuroendocrine tumors. In SCLC, representing 15% of lung cancers, 60-70% of patients showed high expression of DRD2. Checkpoint inhibition has shown some efficacy in lung cancer where PD-L1 inhibitors were approved as first-line therapy in SCLC. SCLC patients rapidly fail chemotherapy, develop resistance to treatment and metastases. These observations suggest a link between DRD2 expression and resistance to treatment, making this receptor an attractive target for multispecific antibody therapy. The VHH components of KJ-101 (anti-DRD2, anti-PD-1 and anti-CD47) produce multiple effects to achieve a strong anti-tumor activity. The anti-DRD2 VHH induces intracellular signaling and suppresses tumor growth via ADCC. Treatment with anti-DRD2 antibody significantly suppressed tumor growth in the DRD2-positive NCI-H510A SCLC model in SCID mice. The anti-PD-1 VHH restores T cell function, and the anti-CD47 VHH recruits T cells without their generalized activation and blocks the interaction between CD47 and SIRPα. The KJ-101 anti-tumor efficacy was tested in several in vivo immuno-oncology xenograft models of human SCLC or TNBC, reconstituted with human PBMC or with CD34+ hemopoietic stem cells. KJ-101 treatment led to tumor regression in the TNBC model, blocked metastases formation in CD34+ humanized NCG mice bearing established NCI-H69 tumors, and blocked metastases formation and increased survival in tail vein metastatic models of SCLC. KJ-101 is produced at a high yield (6 g/L) in a manufacturing cell line. Conventional purification yields 99% purity and notably displays high stability under accelerated stability testing. In conclusion, the trispecific KJ-101 antibody has strong in vivo anti-tumor activity mediated via multiple mechanisms of action, is easily expressed and purified, and is very stable. Together, this data supports the clinical development of KJ-101 in advanced metastatic neuroendocrine cancer indications, including SCLC. Citation Format: Shugang Yao, Hiba Zahreddine, Dominic Hou, Elijus Undzys, Liying Gong, Richard Wargachuk, Xiaowei Wang, Alex Zhou, Lucy Lai, Luis A. Da Cruz, David Young. Pre-clinical development of a dopamine receptor 2, PD-1, and CD47 trispecific antibody for the treatment of solid tumors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5661.

Stem Cell Biology on Autoimmune Disease-Crohn’s Disease, Complex Pathogenesis Cure through Regenerative Disease

The attack on immune system in the gut which leads to bowel obstruction, severe diarrhoea, rectal bleeding are major symptoms in individual’s intestinal tissue. This disease is Crohn’s disease. The inflammation in the intestine is caused due to mucosal immune reactivity to antigen found in the lumen. The cost of cure is significantly higher in terms of health care. Now there is a chance for exploration of stem cell cure for Crohn’s disease. Although surgical restructure is required, the disease seems to appear even after surgery. It rejects restructuring unit. Hence surgery is often a failure. After careful experiments on CD patients, Mesenchymal Stem Cells and Hemopoietic Stem Cells are the best available options to cure CD. This case study shows how stem cells works and its results. The results have restructured the way stem cells have been to put to best use in patients that suffer the most with CD. At certain point, the results have high effects in its clinical emission with no medication required. CD patients had adverse effects while in medication and no serious effects with no medication. The definition of stem cells has been smeared all over this Crohn Disease patients and the results have been amazing.

A new form of familial platelet disorder caused by germline mutations in RUNX1 in a pedigree

Objective: To investigate the clinical and biological characteristics of familial platelet disorder (FPD) with germline Runt-related transcription factor (RUNX) 1 mutations. Methods: Patients diagnosed with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) with RUNX1 mutations from February 2016 to December 2021 in Wuhan No.1 Hospital underwent pedigree analysis and were screened for gene mutations (somatic and germline). Patients diagnosed with FPD with germline RUNX1 mutations were enrolled and evaluated in terms of clinical characteristics and biological evolution. Bioinformatics analysis was used to assess the pathogenicity of mutations and to analyze the effect of mutated genes on the function of the corresponding protein. Results: Germline RUNX1 mutations were detected in three out of 34 patients suffering from MDS/AML who had RUNX1 mutations. A pedigree of FPD with RUNX1 (RUNX1-FPD) c.562A>C and RUNX1 c.1415T>C mutations was diagnosed, and the mutations were of patrilineal origin. Bioinformatics analysis indicated that the locus at positions 188 and 472 in the AML-1G type of RUNX1 was highly conserved across different species, and that variations might influence functions of the proteins. The mutations were evaluated to be highly pathogenic. Of the nine cases with germline RUNX1 mutations: two patients died due AML progression; one case with AML survived without leukemia after transplantation of hemopoietic stem cells; four patients showed mild-to-moderate thrombocytopenia; two cases had no thrombocytopenia. During the disease course of the proband and her son, mutations in RUNX1, NRAS and/or CEBPA and KIT appeared in succession, and expression of cluster of differentiation-7 on tumor cells was enhanced gradually. None of the gene mutations correlated with the tumor were detected in the four cases not suffering from MDS/AML, and they survived until the end of follow-up. Conclusions: RUNX1-FPD was rare. The mutations c.562A>C and c.1415T>C of RUNX1 could be the disease-causing genes for the family with RUNX1-FPD, and these mutations could promote malignant transformation. Biological monitoring should be carried out regularly to aid early intervention for family members with RUNX1-FPD.

Long-term outcomes of corticosteroid graft versus host disease prophylaxis in peripheral blood allogeneic haemopoietic stem cell transplant: a comparative cohort analysis.

Corticosteroids (CSs) have previously been incorporated into graft versus host disease (GVHD) prophylaxis regimens for bone marrow (BM) and haemopoietic stem cell transplant (HSCT). To assess the impact of prophylactic CS in HSCT using peripheral blood (PB) stem cells. Patients were identified from three HSCT centres receiving a first PB-HSCT between January 2011 and December 2015 from a fully human leukocyte antigen (HLA)-matched sibling or unrelated donor for acute myeloid leukaemia or acute lymphoblastic leukaemia. To enable meaningful comparison, patients were divided into two cohorts. Cohort 1 included only myeloablative-matched sibling HSCT, where the only variation in GVHD prophylaxis was the addition of CS. In these 48 patients, there were no differences in GVHD, relapse, non-relapse mortality, overall survival or GVHD-relapse-free-survival (GRFS) at 4 years after transplant. Cohort 2 included the remaining HSCT recipients, where one group received CS-prophylaxis and the non-CS group received an antimetabolite, ciclosporin and anti-T-lymphocyte globulin. In these 147 patients, those receiving CS-prophylaxis experienced higher rates of chronic GVHD (71% vs 18.1%, P < 0.001) and lower rates of relapse (14.9% vs 33.9%, P = 0.02). Those receiving CS-prophylaxis had a lower 4-year GRFS (15.7% vs 40.3%, P = 0.002). There does not appear to be a role for adding CS to standard GVHD prophylaxis regimens in PB-HSCT.

Incidence of Sinusoidal Obstruction Syndrome/Veno-Occlusive Disease and Treatment with Defibrotide in Allogeneic Transplantation: A Multicenter Australasian Registry Study

Sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is an established complication in patients undergoing allogeneic hemopoietic stem cell transplantation (HSCT). Defibrotide is an effective and safe pharmacologic option for treating diagnosed SOS/VOD. By exploring data provided to the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR) by centers in Australia and New Zealand, this study aimed to describe the incidence of SOS/VOD and patterns of defibrotide use from 2016 to 2020. Patients who underwent allogeneic hemopoietic stem cell transplantation between 2016 and 2020 were identified from the ABMTRR. Data were extracted for a total of 3346 patients, 2692 from adult centers and 654 from pediatric centers, with a median follow-up of 21.5 months and 33.3 months, respectively. Descriptive statistics were used to describe the patient population, including the incidence of SOS/VOD and defibrotide use. Comparisons were made between patients without SOS/VOD and those with SOS/VOD, divided into defibrotide and no defibrotide cohorts. Associations with overall survival (OS) and day 100 survival with such variables as sex, age, disease at transplantation, stem cell source, conditioning agents, SOS/VOD diagnosis, and use of defibrotide, were determined. The reported incidence of SOS/VOD was 4.1% in adult centers and 11.5% in pediatric centers. Defibrotide was administered to 74.8% of adult patients and 97.3% of pediatric patients with SOS/VOD. Significant variability in the use, dosage, and duration of defibrotide was seen across the adult centers. The day 100 survival rate and median OS for patients managed with defibrotide was 51.8% and 103 days, respectively, for adult patients and 90.4% and not reached, respectively, for pediatric patients. In adults, older age at transplantation, an HLA-matched nonsibling relative donor, and a diagnosis of SOS/VOD treated with defibrotide were associated with reduced OS. In pediatric patients, the patient and transplantation characteristics associated with reduced OS were a diagnosis of SOS/VOD and a ≥2 HLA-mismatched related donor. A collaborative approach across Australasia to diagnosing and managing SOS/VOD, particularly with respect to consistent defibrotide use, is recommended.

Humanized MISTRG as a preclinical in vivo model to study human neutrophil-mediated immune processes.

MISTRG mice have been genetically modified to allow development of a human myeloid compartment from engrafted human CD34+ haemopoietic stem cells, making them particularly suited to study the human innate immune system in vivo. Here, we characterized the human neutrophil population in these mice to establish a model that can be used to study the biology and contribution in immune processes of these cells in vivo. We could isolate human bone marrow neutrophils from humanized MISTRG mice and confirmed that all neutrophil maturation stages from promyelocytes (CD11b-CD16-) to end-stage segmented cells (CD11b+CD16+) were present. We documented that these cells possessed normal functional properties, including degranulation, reactive oxygen species production, adhesion, and antibody-dependent cellular cytotoxicity towards antibody-opsonized tumor cells ex vivo. The acquisition of functional capacities positively correlated with the maturation state of the cell. We found that human neutrophils were retained in the bone marrow of humanized MISTRG mice during steady state. However, the mature segmented CD11b+CD16+ human neutrophils were released from the bone marrow in response to two well-established neutrophil-mobilizing agents (i.e., G-CSF and/or CXCR4 antagonist Plerixafor). Moreover, the neutrophil population in the humanized MISTRG mice actively reacted to thioglycolate-induced peritonitis and could infiltrate implanted human tumors, as shown by flow cytometry and fluorescent microscopy. These results show that functional human neutrophils are generated and can be studied in vivo using the humanized MISTRG mice, providing a model to study the various functions of neutrophils in inflammation and in tumors.

Multi-component cord blood banking: a proof-of-concept international exercise.

Most public cord blood (CB) banks currently discard more than 80% of umbilical CB units not suitable for hemopoietic stem cell transplant due to low stem cell count. Although CB platelets, plasma, and red blood cells have been used for experimental allogeneic applications in wound healing, corneal ulcer treatment, and neonatal transfusion, no standard procedures for their preparation have been defined internationally. A network of 12 public CB banks in Spain, Italy, Greece, the UK, and Singapore developed a protocol to validate a procedure for the routine production of CB platelet concentrate (CB-PC), CB platelet-poor plasma (CB-PPP), and CB leukoreduced red blood cells (CB-LR-RBC) using locally available equipment and the commercial BioNest ABC and EF medical devices. CB units with >50 mL volume (excluding anticoagulant) and ≥150×109/L platelets were double centrifuged to obtain CB-PC, CB-PPP, and CB-RBC. The CB-RBC were diluted with saline-adenine-glucose-mannitol (SAGM), leukoreduced by filtration, stored at 2-6°C, and tested for hemolysis and potassium (K+) release over 15 days, with gamma irradiation performed on day 14. A set of acceptance criteria was pre-defined. This was for CB-PC: volume ≥5 mL and platelet count 800-1,200×109/L; for CB-PPP: platelet count <50×109/L; and for CB-LR-RBC: volume ≥20 mL, hematocrit 55-65%, residual leukocytes <0.2×106/unit, and hemolysis ≤0.8%. Eight CB banks completed the validation exercise. Compliance with acceptance criteria was 99% for minimum volume and 86.1% for platelet count in CB-PC, and 90% for platelet count in CB-PPP. Compliance in CB-LR-RBC was 85.7% for minimum volume, 98.9% for residual leukocytes, and 90% for hematocrit. Compliance for hemolysis ≤0.8% decreased from 89.0 to 63.2% from day 0 to 15. K+ release increased from 3.0±1.8 to 25.0±7.0 mmol/L from day 0 to 15, respectively. The MultiCord12 protocol was a useful tool to develop preliminary standardization of CB-PC, CB-PPP, and CB-LR-RBC.

Impact of gemtuzumab ozogamicin consolidation on hematopoietic stem cells (HSCs) mobilization in AML: analysis of 20 patients.

Gemtuzumab ozogamicin (GO), is an anti-CD33 monoclonal antibody, approved for AML CD33 + , those patients with low and intermediate-risk who obtain a complete response may also be candidated for consolidation with autologous stem cell transplantation (ASCT). However, there are scant data on the mobilization of hemopoietic stem cells (HSC) after fractionated GO. We retrospectively studied data from five Italian centers and identified 20 patients (median age 54years, range 29-69, 15 female, 15 NPM1mutated) that attempted HSC mobilization after fractionated doses of GO + "7 + 3" regimen and 1-2 cycles of consolidation (GO + HDAC + daunorubicin). After chemotherapy and standard G-CSF, 11/20 patients (55%) reached the threshold of 20 CD34 + /µL, and HSC were successfully harvested, while 9 patients (45%) failed. The median day of apheresis was Day + 26 from the start of chemotherapy (range 22-39days). In good mobilizer patients, the median circulating CD34 + cells were 35.9 cells/µL and the median CD34 + harvested were 4.65 × 106/kg of patients' body weight. With a median follow-up of 12.7months, at 24months from the first diagnosis, 93.3% of all 20 patients were alive and the median overall survival was 25months. The 2-year RFS rate from the timepoint of the first CR was 72.6%, while the median RFS was not reached. However, only five patients underwent ASCT and achieved full engraftment.In conclusion, in our cohort of patients, the addition of GO reduced HSC mobilization and harvesting, which was reached in about 55% of patients. Nevertheless, further studies are warranted to evaluate the effects of fractionated doses of GO on HSC mobilization and ASCT outcomes.

Septic shock in patient undergoing hemopoietic stem cell transplantation. A case report

. Septic shock in patient undergoing hemopoietic stem cell transplantation. A case-report. This case on septic shock is the last contribution proposed on oncology emergencies. It is the case of a 66-year-old man who undergoes an autologous hemopoietic stem-cell transplantation for a multiple myeloma. The case follows the update on hemopoietic stem cell transplantation published in issue 1, 2023. The readers are invited to read the update for a useful guide to answering learning questions.

483 - Incidence of Decreased Bone Mineral Density Post Allogeneic Haemopoietic Stem Cell Transplant: Single Institution Retrospective Analysis

483 - Incidence of Decreased Bone Mineral Density Post Allogeneic Haemopoietic Stem Cell Transplant: Single Institution Retrospective Analysis