Hematopoietic Stem Cell Grafts Research Articles

Inpatient Rehabilitation of Hematopoietic Stem Cell Transplant Patients: Managing Challenging Impairments and Medical Fragility.

Hematopoietic stem cell transplants play an important role in the treatment of cancer, particularly hematologic malignancies. These patients can encounter functional impairments unique to hematopoietic stem cell transplant, including deconditioning, cancer-related fatigue, steroid myopathy, graft versus host disease, and capillary leak syndrome. Medical fragility and increased risk of infection may make rehabilitation challenging on the acute care and postacute care settings. Patients admitted to acute inpatient rehabilitation experience a high rate of transfer to the primary acute service and high rate of mortality after transfer back. Physical medicine and rehabilitation physicians can use a number of strategies to mitigate these patients' risk of medical complications including evidence-based predictive models to assist with postacute rehabilitation triage, physiatry-led consult-based rehabilitation, and oncology hospitalist comanagement on inpatient rehabilitation.

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.

The Non-Hematopoietic Content in Paediatric Autologous Hematopoietic Stem Cell Grafts Is Skewed Towards Regulatory Myeloid and Exhausted Phenotypes

Autologous hematopoietic stem cell transplant (aHSCT) is a central component of paediatric brain tumours and high-risk neuroblastoma management. Standardly, chemotherapy and G-CSF are used to mobilize the CD34+ hematopoietic stem/progenitor cells (HSC), which are used to support hematopoietic recovery following dose chemotherapy. Clinically, the graft infused is defined by solely by the CD34+ content. The non-hematopoietic passenger cells makeup most of the graft and are a mixture of myeloid and lymphoid cells that are potentially biologically active in the post-transplant setting. Here we study the content of the graft, focusing on the phenotypes of the cell populations, to begin to look at how the non-hematopoietic cells may facilitate anti-tumor activity, affect the tumour microenvironment, and/or immune recovery post-transplant. High parameter mass cytometry, with a custom 40-marker panel, was used to characterize 43 autologous cryopreserved grafts from children (median age 39 months, range 14-255 months) undergoing apheresis following chemotherapy and G-CSF mobilization. Healthy G-CSF-mobilized allogeneic donors (allograft) were used as a comparator group (n=10). Young children frequently have robust mobilization (peripheral blood CD34 count range from 100-1800 CD34/µL on day of collection) and generally one day collection will support multiple cycles of high dose therapy (target collections 20 x10 6 CD34+ cells/kg and often over collecting in 2-3 blood volume processed). This results in a product that is rich in CD34+ cells, with intergraft heterogeneity (median 7%; range 0.7-31%), compared to the CD34+ content of allografts (median 1.1%; range 0.3-2.4%) (autograft vs allograft median CD34 difference p<0.00005; Wilcoxon unpaired). There was variability in the non-hematopoietic component in the autografts (median T cells 10.8%; range 0.6 - 51.7%, and median monocytes 18.8%; range 4.1 - 51.4%). The allogeneic products were found to have less variability (T cells: 19.9 - 56%; monocytes: 7.3 - 19.6%). Autografts had increased expression of T cell exhaustion markers, with a median 30.8% (range 14.7 - 88.1%) of T cells expressing TIGIT and 35.1% (range 13.1 - 75.9%) expressing PD1 compared to the allografts (median TIGIT: 15.7%; range 9.3 - 28.7% and median PD1: 11%; range 4.2 - 19.7%). When grafts from high mobilizers (N= 21; >7% CD34+ cells) were analyzed by the actual number of cells infused they had had fewer regulatory cells: monocytic-myeloid derived-suppressor cells (M-MDSCs) (3.6x10 7 cells/kg; range 0.5 - 73.8x10 7; p< 0.0003), non-classical monocytes (0.9x10 7 cells/kg; range 0.5 - 21.3x10 7 cells/kg; p< 0.002) compared to the grafts from lower mobilizers (N = 22; <7.1% CD34+ cells) M-MDSC: median 7.7x10 7/kg; range 0.6 - 21.3x10 7 cells/kg, non-classical monocytes: 1.7x10 7 cells/kg; range 0.05 - 3.7x10 7 cells/kg). T cells and NK cells did not differ between high and low mobilizers. We are seeing significant differences in the regulatory cell populations infused in paediatric aHSCT based on the how robustly a patient mobilizes CD34+ cells after chemotherapy and G-CSF. It is not known whether these differences are clinically significant or affect anti-tumour immunity, tumour microenvironment perturbation, or immune recovery. With this high parameter mass cytometry strategy, we will be able to correlate engraftment kinetics and transplant outcomes (survival, relapse), which will allow us to re-envision how grafts should be optimally manufactured. Controllable variables include the timing of collection (earlier or later in the clinical course), alternative growth factor usage, enrichment or depletion of cell populations in the graft, or post-transplant growth factor administration. We suggest that the aHSCT graft can be thought of as an immunotherapy tool and not just for hematopoietic recovery.

Survey-based assessment of hematopoietic stem cell graft manipulation (minimal) by cell therapy labs supporting hematopoietic stem cell transplants in India

Background aimsHematopoietic stem cell transplants (HSCTs) are increasingly being offered to patients in India for various conditions. The Indian Stem Cell Transplant Registry shows that a total of 2533 transplants were done in India in 2019. MethodsAn epidemiological descriptive cross-sectional survey (55 questions) of centers providing HSCT in India was planned to analyze variations in policies and practices regarding HSCT graft manipulation (i.e., plasma reduction, red blood cell [RBC] depletion and cryopreservation). A total of 63 of 102 centers responded to the survey (response rate, 61.7%), mostly from the northern part of India (27 of 63 [42.8%]). ResultsThe majority of responding centers reported performing >50 HSCTs annually (n = 24 [38%]), and 92% (58 of 63) performed stem cell collections from a pediatric donor/patient (age <18 years). A total of 56 of 63 responding centers indicated that they did product manipulations involving cryopreservation (n = 45), plasma reduction (n = 42) and RBC depletion (n = 28). Cryopreservation was primarily done by blood centers (27 of 45 [60%]), with dimethyl sulfoxide (DMSO) being the primary constituent, used most commonly at a concentration of 5–10% (28 of 45 centers). Dump freezing was most commonly used (27 of 45) with a –80°C deep freezer. A 7-aminoactinomycin D based viability assessment was also most commonly used (30 of 45). Thawing of the product was done mainly at the bedside (30 of 45) using a wet-type thawer (36 of 45), and washing of DMSO was done by a few centers (seven of 45). Plasma reduction and RBC depletion were primarily done for ABO incompatibility at blood centers. ConclusionsThis survey demonstrates the lack of standardization and uniformity in the minimal manipulation of hematopoietic stem cell grafts in centers supporting HSCT in India. This work also highlights the need for more studies and country-specific recommendations to establish best practices.

Loss of Autophagy Activity during Storage of Hematopoietic Stem Cell Grafts Is Associated with Reduced Potency

Maximizing the potency of hematopoietic stem cell (HSC) grafts including cord blood (CB) units (CBU) is essential to minimize risk of engraftment delays and failures. Low cell dose in CB transplantation is partially responsible for the slower engraftment but processing delays could also be at play since CBU can be stored at room temperature (RT) up to 48 hours before cryopreservation. We hypothesized that such prolong storage reduces graft potencies due to a loss in hematopoietic stem cell and progenitors (HSPC) content. CBU were used as HSC graft. Units were split in 2 halves; one processed shortly after collection (&amp;lt;15 hrs, fresh) or after storage at RT (~43 hrs, stored). The impact of storage on graft quality was assessed using standard assays and bioinformatic analysis used to identify molecular pathways impacted by storage. Monitoring assays revealed that all CBU samples passed the minimal FACT-criteria threshold for post-thaw CD34+ cell viability and potency. However, the net number of ISHAGE CD34+ cell counts were reduced in stored samples (-20%, p&amp;lt;0.01). The colony forming-unit (CFU) assay used to measure the impact of storage on potency also revealed a 20% reduction in CFU in stored samples (&amp;lt;0.05, n=7). Losses in potency was confirmed with a second assay, the IL-3-phospho-STAT5 (pSTAT5) assay, which revealed a 10-fold loss in STAT5 signalling in stored vs. fresh CD34+ cells (p&amp;lt;0.0001, n=3). We hypothesized that factors released by CB could be responsible for the reduction of HSPC. In support of this, plasma isolated from stored CBU induced greater apoptosis of CD34+ cells than fresh plasma (+30% AnnexinV+ cells, p&amp;lt;0.01, n=3). This translated into losses of potency detectable after 30 minutes (CFU assay, p&amp;lt;0.001) and with further reduction over time peaking around 2 hours. Next, we sought to identify the molecular programs that govern this detrimental effect within CD34+ cells. Towards this we performed RNAseq analysis of CD34+ cells exposed to fresh or stored plasma for 20 minutes and 4 hours. A time course comparative analysis of differentially expressed genes (DEG, Log 2Fold &amp;gt;1.5, and q&amp;lt;0.05) between cells exposed to fresh vs stored plasma identified a total of 810 DEG genes. Gene ontology enrichment analysis identified autophagy, cell cycle, histone and DNA methylation and mRNA regulation as the major molecular programs that might be up regulated by the paracrine factors from fresh plasma but repressed by those from stored plasma. Autophagy flux assay confirmed that CD34+ cells isolated from stored UCB samples had reduced autophagy activity, and that stored plasma induced a 50% reduction in autophagy flux (p&amp;lt;0.001, n=3). Furthermore, RT-qPCR analysis confirmed that prolonged storage of CBU samples at RT increased the cellular senescence marker p21(CDKN1B), down regulated cell cycle genes ( CDK4 and CDK7) and autophagy genes ( ATG4, ATG12 and BECN1). We hypothesized that re-activation or prevention of autophagy loss could prevent losses of HSPC within CBUs stored at RT. To test this, CBUs were divided and individually supplemented with either autophagy activators (rapamycin or trehalose), autophagy inhibitor (3-methyladenine, 3-MA) or DMSO control and stored up to 43 hours. As expected, the early autophagy inhibitor 3-MA failed to restore HSPC numbers and potency. However, addition of trehalose prior to storage restored 99% of both net number and potency of HSPCs in HSC grafts as measured by the ISHAGE CD34+ counts, CFU and pSTAT5 assays to baseline level (n=3). Interestingly, the near complete restoration mediated by trehalose coincided with restauration of autophagy activity, repression of senescence gene CDKN1B and activation of cell cycle genes. In contrast, rapamycin only partially restored HSPC numbers and potency which coincided with the activation of autophagy genes but not others mentioned above. In conclusion, the loss of potency and viability seen in CBU grafts originates in part by paracrine-mediated mechanisms that lead to loss of autophagy, down regulation of cell cycle regulators and induction of senescence in HSPCs. Interestingly, addition of trehalose as a natural supplement precludes these molecular changes and restores CBU potency during storage. Taken together, these results stress the importance of rapid processing of HSC grafts and identify an attractive new solution to maintain high HSC graft potency post-collection during storage at ambient temperature.

Compassionate Use of Emapalumab in Children with Life-Threatening Disorders: Real-World Data

Introduction: Life threatening hyperinflammation occurs in hemophagocytic lymphohistiocytosis (HLH) and during acute rejection of hematopoietic stem cell (HSC) grafts. Both conditions reflect acute activation of the immune system, in part due to overproduction of proinflammatory cytokines, particularly interferon gamma (IFNγ). Emapalumab, a fully human monoclonal antibody that binds to IFNγ, is approved by the FDA for refractory or recurrent primary HLH (pHLH) or in patients intolerant to conventional therapy. Off-label use of emapalumab has been reported for treatment of secondary HLH (sHLH) and for HSC graft rejection. The European Medicines Agency did not approve emapalumab for the treatment of HLH and many other regulatory authorities, including the Israeli Ministry of Health, have yet to approve emapalumab for clinical use. Pending such regulatory approval, emapalumab is available in Israel exclusively though the Managed Access Request Program (MAP) on a compassionate basis sponsored by Sobi (Swedish Orphan Biovitrum AB,Reg. no. 556038-9321). Experience that accumulates through on- and off-label use of emapalumab obtained via MAP enriches the knowledge base regarding the uses of this drug in the real-world clinical setting. Methods: We summarized the data of patients receiving emapalumab at our tertiary pediatric center. The medication was received after application to the MAP sponsored by Sobi International with import approval of the Israel Ministry of Health on a named-patient basis. Results: Seven patients (Pt) aged 2.5 months-17.5 years were treated with emapalumab between 3/2020-6/2023. Patients 1-5 fulfilled HLH-2004 diagnostic criteria. Indications for the use of emapalumab included treatment of HLH in a newborn with severe hepatotoxicity after treatment with the standard HLH-94 protocol (Pt. 3), treatment of acute graft rejection with recurrence of HLH in a patient with pHLH (Pt.1), secondary HSC graft failure and disease relapse in a child with pHLH (Pt. 4), sHLH with multi-organ failure (MOF) requiring extracorporeal membrane oxygenation (ECMO) (Pts 2&amp;5) and HSC primary graft rejection with suspected 2 nd rejection (Pts.6&amp;7). Table 1 summarizes the clinical characteristics of all cases. The patient outcomes were closely related to their clinical status at treatment initiation. Pt.3 was able to reach remission and successfully bridge to SCT without complications after only 4 doses of VP-16 with continuation therapy using only dexamethasone and emapalumab. Pt.4, who experienced relapsed pHLH with concomitant HSC graft loss, attained complete remission with emapalumab, dexamethasone and IVIG, facilitating a successful second HSC graft. Pt. 1 expired after initial graft failure, severe sepsis and relapse of pHLH. Pts. 2&amp;5, despite showing improvement of their HLH criteria after treatment with emapalumab, succumbed to MOF that was already present when they were referred to our center for ECMO support. Following unsuccessful emapalumab treatment for primary graft rejection, Pts. 6&amp;7 underwent successful 2 nd HSC transplants with early emapalumab treatment for suspected re-rejection. Conclusions: Emapalumab is a safe, effective, and well tolerated treatment for various HLH scenarios, and for similar hyper-inflammatory medical conditions. Administration of emapalumab early in the disease course is likely to be more effective as compared to administration of the drug when MOF has occurred or when the HSC graft has already been rejected. Since these diseases are life-threatening, eliminating delays in procurement of emapalumab is essential to expedite treatment before irreversible organ failure ensues.

Impact of Non-Immune Factors on Platelet Transfusion Responses in an Allo-Immunized Cohort

Background: Patients with hematologic malignancies and/or hematopoietic stem cell transplantation (HSCT) recipients often require platelet transfusion support for extended periods. This can result in platelet transfusion refractoriness (PTR) from HLA alloimmunization in up to 30% of individuals. These medically complex patients may also have splenomegaly, fevers and other factors which contribute to PTR. Consequently, they may demonstrate variability in immediate platelet recovery (at 0-2 hours post-transfusion), and in subsequent platelet consumption (at 18-24 hours) despite receiving HLA-selected platelet products. We sought to examine patient and product related factors which impacted platelet transfusion response in a cohort of HLA-alloimmunized platelet transfusion refractory patients. Methods: From April 2021 to June 2023, HLA-alloimmunized (PRA &amp;gt;50%) subjects who required three or more HLA selected platelet units were identified at the Fred Hutchinson Cancer Center/University of Washington. Data were obtained on patient demographics, diagnoses, Panel Reactive Antibodies (PRA %) and factors shown to be associated with poor platelet responses (spleen size, disseminated intravascular coagulation (DIC), bleeding, selected medications, history of hematopoietic stem cell transplant (HSCT) and/or graft versus host disease (GVHD), ABO compatibility, and product age). Platelet corrected count increments (CCI) were calculated for each transfusion. Non-HLA factors potentially contributing to CCIs at 0-2 and 18-24 hours post-transfusion were compared among HLA-compatible (either 4/4 HLA matched without HLA antigen mismatches, or with permissive mismatches (defined as cumulative a mean fluorescent intensity (MFI) &amp;lt;10,000 on the Luminex donor specific HLA antibody testing platform)) and HLA incompatible transfusions (cumulative MFI &amp;gt;10,000 or random donor apheresis products). Results: Of the 420 patients screened, 75 had sufficient records for inclusion. These subjects received 2729 platelet transfusions, an average of 36 transfusions per patient over 5.2 (± 4.1) months. Post transfusion platelet counts were available for 1528 transfusions. All platelet products were leukoreduced, irradiated, single donor apheresis products. Patients were predominantly Caucasian (70.7%; n=53/75), female (82.7%; n=62/75), aged 57 (±14.9) years. The primary diagnosis was Acute myelogenous leukemia or myeloproliferative disorder in most cases (88%; n=66/75). 58.7% (n=44/75) of patients were HSCT recipients (3 auto-; 41 allo-HSCT). Average PRA among patients was 72.4%±22.2%. 25 patients had splenomegaly. Among HLA-compatible transfusions, average CCIs at 0-2 and 18-24 hours were 17,088 and 6,666. In HLA-mismatched/random donor transfusions, average CCIs at 0-2 and 18-24 hours were 11,489 and 2,786; HLA compatible products increased CCIs by 5,599 and 3880 at 0-2 and 18-24 hours. In both groups splenomegaly had the most consistent association with poor CCI at both time intervals (Figures A and B). Conclusions: In this cohort of individuals with HLA-alloimmunization mediated PTR, the administration of HLA-compatible products offset the impact of other detrimental factors generating adequate CCIs at 0-2 and 18-24 hours. Among patients with splenomegaly, CCIs were lower despite HLA compatible product administration. In the same individuals, HLA-incompatible/random donor products negatively impacted CCIs overall and the negative effect of other concomitant non-immune/product-related factors was additive.Our data highlights the need to account for non-HLA related conditions while evaluating CCI response following each HLA-selected product transfusion, and to further explore any interactions among such factors. Next steps include conducting a multivariate analysis and developing a predictive model for platelet transfusion response in HLA-alloimmunized recipients who have concomitant non-immune or product related risk factors.

P‐BT‐20 | Survey‐Based Assessment of Hematopoietic Stem Cell Graft Manipulation (Minimal) by Cell Therapy Labs Supporting Hematopoietic Stem Cell Transplants in India

P‐BT‐20 | Survey‐Based Assessment of Hematopoietic Stem Cell Graft Manipulation (Minimal) by Cell Therapy Labs Supporting Hematopoietic Stem Cell Transplants in India

Arboviral Risk Associated with Solid Organ and Hematopoietic Stem Cell Grafts: The Prophylactic Answers Proposed by the French High Council of Public Health in a National Context.

Diseases caused by arboviruses are on the increase worldwide. In addition to arthropod bites, most arboviruses can be transmitted via accessory routes. Products of human origin (labile blood products, solid organs, hematopoietic stem cells, tissues) present a risk of contamination for the recipient if the donation is made when the donor is viremic. Mainland France and its overseas territories are exposed to a complex array of imported and endemic arboviruses, which differ according to their respective location. This narrative review describes the risks of acquiring certain arboviral diseases from human products, mainly solid organs and hematopoietic stem cells, in the French context. The main risks considered in this study are infections by West Nile virus, dengue virus, and tick-borne encephalitis virus. The ancillary risks represented by Usutu virus infection, chikungunya, and Zika are also addressed more briefly. For each disease, the guidelines issued by the French High Council of Public Health, which is responsible for mitigating the risks associated with products of human origin and for supporting public health policy decisions, are briefly outlined. This review highlights the need for a "One Health" approach and to standardize recommendations at the international level in areas with the same viral epidemiology.

Clonal hematopoiesis with DNMT3A and PPM1D mutations impairs regeneration in autologous stem cell transplant recipients.

Clonal hematopoiesis (CH) is an age-related condition driven by stem and progenitor cells harboring recurrent mutations linked to myeloid neoplasms. Currently, potential effects on hematopoiesis, stem cell function and regenerative potential under stress conditions are unknown. We performed targeted DNA sequencing of 457 hematopoietic stem cell grafts collected for autologous stem cell transplantation (ASCT) in myeloma patients and correlated our findings with high-dimensional longitudinal clinical and laboratory data (26,510 data points for blood cell counts/serum values in 25 days around transplantation). We detected CHrelated mutations in 152 patients (33.3%). Since many patients (n=54) harbored multiple CH mutations in one or more genes, we applied a non-negative matrix factorization (NMF) clustering algorithm to identify genes that are commonly co-mutated in an unbiased approach. Patients with CH were assigned to one of three clusters (C1-C3) and compared to patients without CH (C0) in a gene specific manner. To study the dynamics of blood cell regeneration following ASCT, we developed a time-dependent linear mixed effect model to validate differences in blood cell count trajectories amongst different clusters. The results demonstrated that C2, composed of patients with DNMT3A and PPM1D single and co-mutated CH, correlated with reduced stem cell yields and delayed platelet count recovery following ASCT. Also, the benefit of maintenance therapy was particularly strong in C2 patients. Taken together, these data indicate an impaired regenerative potential of hematopoietic stem cell grafts harboring CH with DNMT3A and PPM1D mutations.

An overview of cord blood stem cell transplantation in Hong Kong

Haematopoietic stem cell graft derived from cord blood is standard therapy for several haematological malignancies and other diseases. The study reports cases of public and private (family) cord blood biobanking services and the related hematopoietic stem cell transplantation ever performed in Hong Kong. The published original research papers and review articles from inception to Nov 2022 have been searched for on Pubmed, Microsoft Academic Search, and Google Scholar to identify reports on existing or terminated cord blood biobanking and transplantation service in Hong Kong. Moreover, all data publicly available on the official websites of the local cord blood banks and local mainstream media has been analysed. The public Hong Kong Red Cross Blood Transfusion Service delivers the highest quantity of haematopoietic stem cell transplants. Among the private sector, HealthBaby releases the most cord blood units for clinical use in diseases in both autologous and allogeneic administration, followed by Cordlife HK. Both public and private (family) cord blood biobanks have been and continue to contribute to the Hong Kong cord blood donor registry. However, the growth of the cord blood inventory is detrimental to donor-recipient matching for lifesaving therapy.

Ongoing Risk of Unrelated Donors Testing Positive for COVID-19 Following Medical Clearance and Impact on Operations: A Report from the National Marrow Donor Program

The global demand for hematopoietic stem cell grafts from unrelated donors (URD) continues to grow despite the COVID-19 pandemic (WMDA report 2021). The pandemic has challenged URD registries to adapt to the changing landscape of SARS-CoV-2 variants. While travel logistics have improved, the Omicron surge, particularly with the BA.5 subvariant, continues to place donors and patients at risk of developing COVID-19. The National Marrow Donor Program (NMDP) and other registries mandated cryopreservation at the beginning of the pandemic and reinstituted a mandate in January 2022 in response to the Omicron surge. NMDP removed the mandate in March 2022 but has continued to strongly recommend cryopreservation for patient safety. In this analysis, we sought to quantify the risk of donors becoming infected with COVID-19 from May 2021, when we began collecting more detailed information, to present (data cutoff 6/30/22). We quantified the total number of donors testing positive following medical clearance (Table 1). In aggregate, we observed a 2.4-fold increase in the absolute number of donors testing positive following clearance over the first half of 2022, compared to the previous first half of 2021 (53 versus 22). We next analyzed numbers based on age of intended recipients (pediatric vs adult) and graft sources (bone marrow, BM vs. peripheral blood, PB). 57 and 19 donors tested positive prior to planned collection for adults and pediatric recipients, respectively. For BM and PB, the absolute numbers were 22 and 54, respectively. Given that requests for a fresh product may place recipients at risk for prolonged pancytopenia if a donor tests positive following the initiation of conditioning but prior to graft collection, we quantified the number of donors testing SARS-CoV-2 positive based on whether the transplant center (TC) requested a fresh or cryopreserved URD graft. 33 donors who tested SARS-CoV-2 positive prior to a planned fresh product, compared to 43 donors when cryopreservation was planned. Donor SARS-CoV-2 positivity led to HCT postponement for all patients who had not yet started conditioning. 20 recipients of planned fresh products had already initiated conditioning at the time the donor tested SARS-CoV-2 positive. Of these 20 recipients, 9 eventually received a transplant with the same URD, 1 received a different URD provided by another registry, 1 received a cord blood unit, 4 received a different, but similar in match (8/8 or 7/8) URD, and 5 cases are open (i.e., infusion status unknown/pending). Realizing donor and staff safety is paramount, NMDP conducted a survey of our network apheresis centers (ACs) and BM collection centers posing a hypothetical question: "Would you collect a SARS-CoV-2 positive donor who was asymptomatic if the recipient had already started conditioning?" Of the 45 ACs responding to the survey, 65% replied no. Of the 32 responding BM collection centers, 50% replied no. Thus, in the majority of cases, an asymptomatic URD would not be collected. Overall, requests to NMDP for a cryopreserved URD product have varied over the course of the pandemic based on periodic mandates, TC preference, and requested graft source (Figure 1). While <10% of NMDP products were cryopreserved prior to the pandemic, >90% of products have been cryopreserved during the mandate periods (3/23/2020-8/10/2020 and 1/17/2022-3/14/2022). Rates have also varied by graft source: 68% PB products and 27% BM products are currently being cryopreserved. We analyzed practice patterns by TC to determine the degree of variation in requests for fresh versus cryopreserved products. While the median request rate for cryopreserved NMDP products throughout the pandemic is 58%, the lowest quartile included 10 TCs who requested >20 products over the course of the pandemic with cryopreservation request rates ranging from only 19-33%. In conclusion, the COVID-19 pandemic continues to pose logistical challenges to the NMDP and other global URD registries, particularly during the most recent Omicron subvariant BA.5 surge. TCs ordering fresh products for infusion following initiation of conditioning should be aware of and discuss with patients and inpatient teams the ongoing risk of patients undergoing conditioning without an URD product available for infusion on the day of intended transplantation. These sites should have in place a viable back-up donor plan or stem cell source in the event the intended donor tests positive. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Molecular methods in identifying the true grouping of erythrocytes in patients with blood system diseases before transplantation of hematopoietic stem cells and their donors

Background. when transplantation of hematopoietic stem cells (HSC) is performing, it is necessary to take into account the incompatibility of the donor and recipient in terms of erythrocyte antigens in order to assess the possibility of immunological complications during HSC transfusion and/or graft engraftment (acute hemolysis, delayed hemolysis, etc.). The results of serological research methods do not always allow identifying the true group affiliation due to posttransfusion chimerism in patients and/or the presence of antigen allelic polymorphism.Aim. To establish the frequency of ABO-incompatible allo-HSC transplantations in the National Research Center for Hematology, to determine by molecular methods the group affiliation of patients with a weakened expression of antigens and/or after multiple blood transfusions before HSC transplantation, to clarify the blood type of HSC donors with a weakened expression of antigens.Materials and methods. The blood of 270 HSC donor-recipient couples was examined. The blood group of the ABO, Rhesus, MNS, Kell systems was determined in a plane agglutination test using the corresponding IgM class Tsoliclones and in gel cards. Genotyping was performed by polymerase chain reaction with primers to identify the genes of the ABO, Rhesus, Kell, and MNS systems.Results. In 2018-2020 270 HSC transplantations were performed at the National Research Center for Hematology. In 141 (52.22 %) couples, incompatibility of the donor and recipient according to the ABO system was revealed: major - 23.33 %, minor - 20 %; bidirectional - 8.89 %. problems in assessing of serological results were observed in 97 (36.3 %) patients: in 78 patients with post-transfusion chimerism and 19 patients with weakened antigen expression; in 15 (5.56 %) HSC donors: in 4 due to the lack of information about the blood group of cryopreserved cells, in 10 due to weakened antigen expression, in 1 to search for informative markers for monitoring HSC engraftment. The results of the study demonstrated that the percentage of agglutinated erythrocytes in post-transfusion chimerism cannot be a reliable criterion for establishing the true phenotype of a patient. In donors and patients with weakened expression of antigens, the presence of ABO*O1, -A1, -A2, -B1, RHD weak type 1, RHD weak type 2, RHD weak type 3, RHCE*Cw genes was confirmed. for the first time in Russia gene RHCE*01.38 was found.Conclusion. The prevalence of ABO-incompatible HSC transplants was noted. problems with serological determination of the blood group in a third of patients before HSC transplantation arose due to the presence of post-transfusion chimerism and weakened expression of antigens. Determining of the genotypes of HSC donors is necessary when the expression of antigens is weakened and cryopreserved cells are received. The percentage of agglutinated erythrocytes in post-transfusion chimerism cannot be a reliable criterion for establishing the true phenotype of a patient. Detection of mixed chimerism in the determination of group factors by serological methods is an indication for genotyping, especially in the context of the predominance of incompatible HSC transplantations.

Milestones in Hematology and Oncology: From Fatal to Curable Disease.

Background: The comprehensive management of patients with Hodgkin's lymphoma (HL) is a success story in contemporary oncology. Over the past decades, the survival rate of patients with HL has significantly improved. The objective of this analysis is to evaluate and document the progress in the management of Hodgkin's lymphoma in patients in our country, reflected in their vital statistics, over time periods defined by the respective standard of treatment. Material and methods: The present study is designed as a retrospective-prospective study. We analyzed different modalities of treatment and compared 5 and 10-year overall survival rates in a total of 588 Hodgkin's lymphoma patients treated at the University Clinic for Hematology in Skopje during two consecutive time periods, before 2000 and after 2000. The entire observation period is from 1980 to 2020. All patients are above the age of 14, with a documented histopathological diagnosis of Hodgkin's lymphoma and with evaluable medical documentation, including clinical and laboratory data on their initial condition, the administered therapy, as well as the clinical follow-up of the patients. Results: The basic clinical features of the analyzed population across the two periods correlate with those reported in the relevant medical literature, with only slight deviations. Ten-year overall survival rates improved by 31.7% through the two calendar periods. During the last two decades of the previous century (1980-2000) the initial treatment options were COPP and COPP-like regimens for the vast majority of patients (94.7%), leading to disease remission in 80% of them. After 2000, 95.8% of de novo diagnosed patients have been treated with ABVD chemotherapy as a frontline choice and the complete response rate is 88.4%. We confirmed the superiority of ABVD in terms of efficacy, improved tumor and disease control, as well as its long-term clinical outcome. While in the past we had very limited options for relapsed/refractory HL patients, the analysis of the results of HL patients treated with various therapeutic approaches in the latter period, defines BEACOPP as the preferred choice. High-dose chemotherapy, followed by autologous hematopoietic stem cell graft, as a strategy for our R/R patients in the timeframe after 2000, ensures a 5-year overall survival for 51% of them, whereas 45% of the patients survive more than 10 years. Conclusion: This analysis from our Hodgkin's lymphoma database illustrates that there has been tremendous improvement in the long-term survival rates since the turn of this century. At our institution we strive to implement positive trends in practice, as suggested by relevant guidelines, regarding the evolution and progress in the diagnostic workup, treatment, and the overall management of patients with Hodgkin's disease. The objective would be to secure favorable vital statistics for our patient population, now reaching 83.5% at 10 years, which closely correlates with the data of more developed countries and centers. In future clinical trials we will also evaluate the efficacy of brentuximab-vedotin and new PD-1 blocking antibodies.

90 - Role of Hematopoietic Stem and Progenitor Cell (HSPC) Graft Composition on the Post HSCT Engraftment Kinetics

90 - Role of Hematopoietic Stem and Progenitor Cell (HSPC) Graft Composition on the Post HSCT Engraftment Kinetics

The Hematology of Tomorrow Is Here-Preclinical Models Are Not: Cell Therapy for Hematological Malignancies.

Simple SummaryCell therapy is revolutionizing the prospect of deadly hematological malignancies such as high-risk acute myeloid leukemia. Stem cell therapy of allogeneic source from compatible human leukocyte antigen donor has exceptional success promoting durable remissions, but the rate of relapse is currently still high and there is transplant-related mortality. This review presents the current knowledge on the clinical use of mesenchymal stromal cells to improve outcomes in hematopoietic stem cell transplants. As an alternative or adjuvant approach to prevent relapse, we summarize the status of the promising forms of cellular immunotherapy aimed at targeting not only the bulk but also the cells of origin of leukemia. Finally, we discuss the available in vivo models for disease modelling and treatment efficacy prediction in these contexts.The purpose of this review is to present the current knowledge on the clinical use of several forms of cell therapy in hematological malignancies and the preclinical models available for their study. In the context of allogeneic hematopoietic stem cell transplants, mesenchymal stromal cells are pursued to help stem cell engraftment and expansion, and control graft versus host disease. We further summarize the status of promising forms of cellular immunotherapy including CAR T cell and CAR NK cell therapy aimed at eradicating the cells of origin of leukemia, i.e., leukemia stem cells. Updates on other forms of cellular immunotherapy, such as NK cells, CIK cells and CAR CIK cells, show encouraging results in AML. The considerations in available in vivo models for disease modelling and treatment efficacy prediction are discussed, with a particular focus on their strengths and weaknesses for the study of healthy and diseased hematopoietic stem cell reconstitution, graft versus host disease and immunotherapy. Despite current limitations, cell therapy is a rapidly evolving field that holds the promise of improved cure rates, soon. As a result, we may be witnessing the birth of the hematology of tomorrow. To further support its development, improved preclinical models including humanized microenvironments in mice are urgently needed.

Haploidentical Donor-Derived CAR-T Cells Are Safely and Effectively Co-Infused with the Haploidentical Graft, Depleted of Ab T Cells: Report of Case Series

IntroductionAutologous chimeric antigen receptor (CAR) T cells induce high rate of deep remissions among children with relapsed/refractory B-precursor acute lymphoblastic leukemia (R/R B-ALL). In a significant proportion of patients true cure is achieved only with HSCT as post-CAR-T consolidation. Seeking to combine the cytoreductive and curative power of HSCT with the antigen-specific activity of CAR-T we devised an approach with simultaneous infusion of haploidentical ab T cell-depleted graft and CAR-T cells, derived from the same donor. The approach was offered to patients with R/R B-ALL on a compassionate use basis and here the first experience is summarized.Patients and methodsA total of 11 patients with relapsed/refractory BCP-ALL (n-10) and Burkitt leukemia(n-1), (5 female, 6 male, median age 8,3 y) were treated. Three patients had relapsed BCP-ALL after both haploidentical HSCT and autologous CD19 CAR-T cell, 3 after haploidentical HSCT, 2 after autologous CD19 CAR-T cell, 3 after intensive chemotherapy +/- blinatumomab (n=2).Seven patients had CD19 and CD22 positive leukemic cells in bone marrow (MRD+ n=1, >20% blasts n=6), 2 pts had MRD-level disease with CD22 positive blast cells and 2 pts were in CR2.Peripheral blood mononuclear cells used to produce CAR T cells were provided by the patient's transplant donor.The CliniMACS Prodigy T cell transduction (TCT) process was used to produce CD19 and СD19/22CAR-T cells.Five (45%) pts received treosulfan-based myeloablative preparative regimen, while TBI-based regimen was used in 6 (55%) pts. GvHD prophylaxis included tocilizumab at 8 mg/kg on day -1 and abatacept at 10 mg/kg on day -1, +7, +14, +28.Final product was administered without cryopreservation to the patients: 10 pts received allogeneic CAR T cell with haploidentical (n=10) and match related (n=1) TCRαβ-depleted graft (CD19 CAR- T cell n=1 and CD19/22 CAR- T cell n=10). The CAR-T cell product was administered at a dose of 0,1*10 6/kg of CAR-T cells in all pts. The median dose of CD34+ cells was 8.5 x10 6/kg (range 5-15), αβ T cells - 56x10 3/kg (range 9-172).ResultsPrimary engraftment was achieved in 10 of 11 pts (non-engraftment patient relapsed early), the median time to neutrophil and platelet recovery was 13 and 14 days, respectively.Cytokine release syndrome occurred in 7 patients (63%) and all were grade ≤3. Six patients (54%) had neurologic events (ICANS grade 3, n=1). No aGVHD 3-4 were observed, 4 pts developed grade 2 aGVHD (skin and gut).The median time to CAR-T cell peak expansion was 14 days (7-28). The median time to CAR-T cell persisted was 6 months (2-12) and B cell aplasia was 7 months.All engrafted patients achieved CR (MRD negative) at day +28 after CAR-T cell therapy, one patient died due to Mucormycosis at day +31. One patient relapsed after 2 months after HST. Eight patients are alive in CR with a median follow up 291 days (85-388).ConclusionOur early experience suggests that haploidentical CAR-T cells can be safely infused simultaneously with the hematopoietic stem cell graft on the platform of ab T cell depletion. The infusions did not compromise engraftment and GVHD control, while specific CAR-T toxicity was mild and manageable. We have documented allogeneic haploidentical CAR-T expansion and persistence. Prospective testing of the approach is warranted. DisclosuresMaschan: Miltenyi Biotec: Speakers Bureau.

Allogeneic Stem Cell Transplantation with Omidubicel: Long-Term Follow-up from a Single Center

Allogeneic Stem Cell Transplantation with Omidubicel: Long-Term Follow-up from a Single Center

ATG and Post-Transplant Cyclophosphamide Predisposes to Inferior Outcome When Using Cryopreserved Stem Cell Grafts

BackgroundDuring 2020, the novel COVID-19 pandemic lead to cryopreservation of allogeneic hematopoietic stem cell (HSCT) grafts based on NMDP and EBMT recommendations, to secure grafts before start of conditioning chemotherapy. We examined the impact of this change in practice on patient outcomes.MethodsWe retrospectively analyzed the outcomes of 483 patients who received HSCT between Aug 2017 and Aug 2020, at Princess Margaret Cancer Centre, Canada, comparing the outcomes between those who received cryopreserved (CRYO, n=135) or fresh peripheral blood stem cell grafts (FRESH, n=348). Median follow-up: 12.3 months.Probability of overall survival (OS) was calculated using the Kaplan-Meier product-limit method and heterogeneity of time-to-event distribution functions were compared by the log-rank test. Cumulative incidences of aGvHD and cGvHD, relapse, and non-relapse mortality (NRM) were estimated using the cumulative incidence method considering competing risk, and groups were compared using Gray's test. Death was considered as a competing event for relapse, aGvHD and cGvHD, and relapse was considered a competing event for NRM, aGvHD and cGvHD.ResultsMedian age was 58y; 54.5% were males. Acute myeloid leukemia was commonest HSCT indication (n=248, 49.1%). Donors: MUD 10/10 n=233; MUD 9/10 (MMUD) n=48, matched related donor (MRD) n=112, Haploidentical n=88. Transplant conditioning: 79 (23%) and 23 (17%) patients received myeloablative conditioning (MAC) in the FRESH and the CRYO groups, respectively (p ns). In the FRESH group, 253 (73%) patients and 114 (84%) patients in the CRYO group received ATG followed by posttransplant cyclophosphamide (PTCy) and Cylosporine GvHD prophylaxis.OS at the 2y timepoint, FRESH group (n=348), was 67.0% (61.1-72.3%), compared to 48.7% (38.1-58.4%) for patients in the CRYO group (n=135), p=0.002, Figure 1a. This was mainly due to MRD cohort outcomes: 2y OS in MRD FRESH group (n=65), was 85.2% (73.3-92.0%), compared to 45.1% (29.9-59.1%) in MRD CRYO group (n=47), p<0.001, Figure 2a. Multivariate analysis (MVA) for OS, significant factors were increasing patient age, DRI high/v.-high, HCT-CI ≥ 3, Donors: Haplo and MMUD, cryopreservation, Table 1.NRM at 1y for FRESH (n=348) 17% (13.2-21.2) vs CRYO (n=135) 22.1 % (14.8-30.4), p ns . However, in the MRD cohort, NRM at 1y for FRESH group (n=65), was 1.5% (0.1-7.4%), compared to 15.4% (6.6-27.4%) for CRYO group (n=47), p=0.003, Figure 2b . On MVA, NRM adverse significant factors were patient age, DRI high/v.-high, Donors: Haplo and MMUD, Table 1.Cumulative incidence (CI) of relapse at 2y for FRESH 22.4% (17.5-27.7) vs CRYO 27.0 % (18.8-35.9) p=0.07 .The CI of moderate-severe cGvHD at 1y for FRESH group (n=315) was 21.5% and 10.8% in the CRYO group, p=0.027, Figure 1c . Patients with FRESH 10/10 MUDs (n=180), had CI of moderate-severe cGvHD at 1y of 20.6%, compared to CRYO 10/10 MUDs (n=35), 6.0% p ns for MUDs; FRESH MRD (n=64) CI was 30.1%; and CRYO MRD (n=43) 10.3%, p=0.008 for MRD, Figure 1d. On MVA, significant adverse factors for chronic GvHD were increasing donor age, male recipient/female donor, whilst graft CRYO was protective, Table 1.GvHD-and Relapse free Survival (GRFS) at 2y for FRESH 54.0% (47.9-59.6) vs CRYO 43.4% (33.4-53.0) p<0.05, Figure 1b. However, in the MRD cohort, GRFS at 2y in FRESH group (n=65), was 74.2% (61.3-83.4%), compared to 40.7% (26.3-54.6%) for CRYO group (n=47), p=0.001; other donor types no difference, Figure 1c. On MVA, significant factors correlated with worse GRFS were: DRI high and very-high, cryopreservation, Donors: Haplo and MMUD, Table 1.Compared to FRESH group, CRYO group experienced reduced cGvHD, delay in neutrophil engraftment, higher graft failure and increased CMV reactivation, with no difference in relapse incidence or acute GvHD.ConclusionCryopreservation was associated with inferior outcomes post-HSCT particularly in the MRD cohort, possibly due to combination ATG and post-transplant cyclophosphamide impacting differential tolerance to cryopreservation on components of the stem cell graft; further studies are warranted to elucidate mechanisms for this observation. [Display omitted] DisclosuresLaw: Novartis: Consultancy; Actinium Pharmaceuticals: Research Funding. Lipton: Bristol Myers Squibb, Ariad, Pfizer, Novartis: Consultancy, Research Funding. Kim: Bristol-Meier Squibb: Research Funding; Paladin: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Mattsson: MattssonAB medical: Current Employment, Current holder of individual stocks in a privately-held company.

Reduced Intensity Hematopoietic Cell Transplantation Improves Cerebral Hemodynamics in Children with Sickle Cell Disease

IntroductionAllogeneic hematopoietic cell transplantation (HCT) is increasingly being utilized in patients with sickle cell disease (SCD) to prevent progressive organ dysfunction, including for primary or secondary stroke prevention. However, outcomes after HCT have mostly been evaluated using broad measures such as overall survival and event free survival with limited direct physiologic evidence of improved cerebral hemodynamics. Cerebral blood flow (CBF; mL blood/100 g tissue/min) is increased in SCD to compensate for chronic anemia, reduced oxygen carrying capacity and to maintain adequate oxygen delivery to the brain tissue. In SCD patients, CBF is inversely associated with intelligence quotient (Strouse JJ, et al. Blood. 2006;108(1):379-381.) and working memory (Prussien KV, et al. Stroke. 2021;52(5):1830-1834.) and has been shown to improve with blood transfusions (Guilliams KP, et al. Blood. 2018;131(9):1012-1021.). Assessment of CBF may help predict long-term neurocognitive outcomes in patients with SCD and assess therapeutic responses to therapies. Additionally, the high metabolic demand of the brain potentially makes assessment of CBF a sensitive predictor of future multiorgan damage in patients with SCD and hence may be useful to help determine eligibility of patients for curative therapies.MethodsWe performed anatomical and hemodynamic magnetic resonance imaging (MRI) of the brain prior to, and at 6 months after HCT in children with SCD undergoing a reduced intensity conditioning based HCT on a clinical study (NCT04362293). All patients received pretransplant conditioning with hydroxyurea, azathioprine, alemtuzumab, thiotepa and low dose total body irradiation (200-400 cGy). All patients received an unmanipulated mobilized peripheral blood derived hematopoietic stem and progenitor cell graft. One patient who received the graft from a haploidentical (HAPLO) donor also received post-transplant cyclophosphamide. Graft versus host disease prophylaxis comprised of sirolimus. A 3-dimensional (3D) T1 sequence was used for gray/white matter segmentation. 3D-pulsed arterial spin labeling (ASL) perfusion imaging (3 mm isotropic) was acquired to measure resting CBF. Mean CBF values were calculated from gray matter. Mean ± standard deviation and median values for various variables are presented.ResultsFour consecutive patients had 2 serial MRIs performed (one before HCT and another 6 months after HCT). Median age at HCT was 14.5 years. Indications for HCT, donor type and whether patients were receiving chronic transfusion therapy (CTT) prior to HCT are indicated in the Table. No patient had prior evidence of overt stroke. All patients engrafted and had >99% donor myeloid chimerism at the time of the post-HCT imaging. Mean pre-HCT hemoglobin was 8.7 ± 0.8 g/dL (median 8.6 g/dL) and it increased to 12.5 ± 2.1 g/dL (median 12.4 g/dL) at 6 months after HCT. All patients exhibited elevated resting CBF values prior to HCT (123.8 ± 32.2 mL blood/100 g tissue/min, median 112.8 mL blood/100 g tissue/min), that decreased following HCT (71.1 ± 32.1 mL blood/100 g tissue/min, median 72.8 mL blood/100 g tissue/min) (Table and Figure). None of the patients had any clinical neurological complications or imaging evidence of new infarcts or anatomical abnormalities in the follow up period.ConclusionOur preliminary results indicate that it is feasible to quantify CBF in patients with SCD before and after HCT using MRI. We demonstrate that cerebral hemodynamics improve after HCT in children with SCD, indicated by a decrease in CBF to near normal values (normal CBF ~80 mL blood/100 g tissue/min). The more substantial changes (-50% and -78%) are seen in children who were not receiving CTT, suggesting that CTT might partially mitigate CBF elevation prior to HCT. Nevertheless, 2 patients receiving CTT prior to HCT also had a further modest decrease in CBF after HCT (-5% and -18%). We plan to follow these changes at serial time points annually after HCT and correlate them with changes in neurocognitive functioning and other functional MRI measures. Improved CBF is expected to reduce stroke risk and may also preserve or improve neurocognitive functioning, and prospective monitoring of these outcomes are underway.Data on all the study participants who have undergone an HCT and had 2 serial MRIs performed by the ASH annual meeting will be presented. [Display omitted] DisclosuresSharma: Vertex Pharmaceuticals/CRISPR Therapeutics: Other: Salary support paid to institution; Medexus Inc: Consultancy; CRISPR Therapeutics: Other, Research Funding; Novartis: Other: Salary support paid to institution; Spotlight Therapeutics: Consultancy; Vindico Medical Education: Honoraria. Triplett: Miltenyi: Other: Travel, meeting registration. Hankins: Vindico Medical Education: Consultancy; UpToDate: Consultancy; Global Blood Therapeutics: Consultancy; Bluebird Bio: Consultancy.