Donor Stem Cell Transplantation Research Articles

5 years DKMS Chile: approach, results and impact of the first unrelated stem cell donor center in Chile.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is performed worldwide to treat blood cancer and other life-threatening blood disorders. As successful transplantation requires an HLA-compatible donor, unrelated donor centers and registries have been established worldwide to identify donors for patients without a family match. Ethnic minorities are underrepresented in large donor registries. Matching probabilities are higher when donors and patients share the same ethnic background, making it desirable to increase the diversity of the global donor pool by recruiting donors in new regions. Here, we report the establishment and the first 5 years of operation of the first unrelated stem cell donor center in Chile, a high-income country in South America with a population of over 19 million. We used online and in-person donor recruitment practices through patient appeals and donor drives in companies, universities, the armed forces, and public services. After confirmatory typing donors were subjected to medical work-up and cleared for donation. We recruited almost 170,000 donors in 5 years. There were 1,488 requests received for confirmatory typing and donor availability checks, of which 333 resulted in medical work-up, leading to 194 stem cell collections. Products were shipped to Chile (48.5%) and abroad. Even when the COVID-19 pandemic challenged our activities, the number of donors recruited and shipped stem cell products remained steady. In Chile there was an almost 8-fold increase in unrelated donor transplantation activity from 16 procedures in 2016-2018 to 124 procedures in 2019-2021, mainly for pediatric patients following the center's establishment. We estimate that 49.6% of Chilean patients would find at least one matched unrelated donor in the global DKMS donor pool. Establishing a DKMS donor center in Chile has significantly increased donor availability for Chilean patients and contributed to an increase of unrelated donor stem cell transplant activity.

FRI100 Lipoprotein X In Graft Vs. Host Disease Affecting Liver

Abstract Disclosure: D. Vedamurthy: None. C. Vitali: None. M. Cuchel: None. D. Soffer: None. D. Rader: None. Introduction: Lipoprotein-X (LpX) is an abnormal lipoprotein rich in phospholipid and unesterified cholesterol (UC) found in patients with cholestatic liver disease, lecithin-cholesterol acyl transferase (LCAT) deficiency, and after lipid emulsion infusion. LpX has been detected in patients with graft-versus-host disease (GVHD) of the liver. Cholestasis leads to the accumulation of bile salts and UC in the circulation, promoting the formation of LpX. This condition is often not well-recognized, partly because the detection of LpX is technically challenging and requires specialized laboratory assays. Case Description: A 66-year lady with acute myeloblastic leukemia (AML) underwent an allogeneic matched unrelated donor stem cell transplant (SCT) which was complicated by graft-versus-host disease (GVHD) affecting the liver, eyes, lungs, and skin. Past medical history includes hypertension. Family history was significant for coronary artery disease in the mother. She is a reformed smoker. Her post-transplant course was highly complicated with infections, GVHD affecting the liver, eyes, lungs, and skin, and vascular events including myocardial infarction and stroke. Laboratory testing revealed abnormal liver enzymes (ALT=268, AST=173, ALKP =402 U/L), and a markedly abnormal lipid profile (TC=500, Non-HDL-C=358, TG= 345 mg/dL). Her thyroid panel and viscosity were normal, but apolipoprotein B levels were discordantly low (77mg/dL). The ratio of ApoB: Non-HDL cholesterol was abnormally low (0.215). She was started on ezetimibe, evolocumab, and omega-3 fatty acids by her neurovascular team for cardiovascular risk reduction. A physical exam revealed a thin, frail woman with mild oral and nail GVHD changes. The rest of the exam was notable for the abdomen showing chronic patchy hyperpigmentation with sclerodermatous changes anteriorly and posteriorly. She had no significant focal neurologic deficits. Her lipid levels were improved with therapy, but TC, non-HDL-C, UC, and triglycerides levels were still elevated (TC=353, non-HDL=258, UC=163, TG=414 mg/dL), UC: TC ratio was high (0.46). FPLC separation of TRL-depleted plasma revealed the presence of LpX. LpX is not very atherogenic, and we recommended continuing current medical therapy as the serum viscosity was within normal limits. Conclusion: The presence of LpX should be suspected in the setting of GVHD accompanied by markedly elevated TC. LpX may cause hyperviscosity, which can induce end-organ ischemia. While the direct assessment of LpX is challenging and requires specialized techniques, ApoB and non-HDL-C levels are available in most clinical laboratories, and a very low ApoB: Non-HDL-C ratio in GVHD patients may indicate the presence of LpX. The treatment goal is to resolve the underlying causes of cholestasis. If hyperviscosity is present, Lp-X can be acutely treated by plasma exchange or lipoprotein apheresis. Presentation: Friday, June 16, 2023

Expression and Prognostic Impact of HK2 in Bone Marrow of Patients with Newly Diagnosed Acute Myeloid Leukemia

To detect the expression level of HK2 gene in the bone marrow of newly diagnosed patients with acute myeloid leukemia (AML) and investigate its influence on the clinical characteristics and prognosis. The expression level of HK2 gene in the bone marrow of 90 newly diagnosed patients with AML that accompanying clinical characteristics and survival status were detected by RT-qPCR, and compared with 18 allogeneic hematopoietic stem cell transplantation (allo-HSCT) donors. The Chi-square test, Kaplan-Meier survival analysis, and Cox proportional hazards regression model were used to analyze the correlation of HK2 expression level with clinical characteristics and prognosis. Compared with allo-HSCT donors, the HK2 expression was significantly increased in newly diagnosed AML patients (P <0.01). Compared with patients with total response (OR, complete response + complete response with incomplete hematologic recovery) after 2 courses of induction chemotherapy, the expression of HK2 in patients without OR was significantly increased (P <0.05). There was a significant difference in the relative expression of HK2 between patients with and without OR after 2 courses of induction therapy (P <0.001). The median survival time of patients with high expression of HK2 was significantly shorter than that of patients with low expression of HK2 (P <0.05). The multivariate Cox proportional hazards regression analysis showed that prognostic stratification, the expression level of HK2, and whether two courses of induction therapy achieved OR were independent factors affecting the prognosis of AML patients (P <0.05). Compared with allo-HSCT donors, the expression level of HK2 gene is increased in the bone marrow of newly diagnosed AML patients. The prognosis of patients with high expression of HK2 is poor. The expression level of HK2 is an independent factor affecting the prognosis of AML patients.

Effectiveness of single-dose 6 mg pegfilgrastim in mobilizing peripheral blood stem cells in allogeneic hematopoietic cell transplantation donors.

A single injection of 12 mg pegfilgrastim was used to mobilize peripheral blood progenitor cells (PBPCs) from healthy donors in some studies. The purpose of this study was to determine if 6 mg of pegfilgrastim was effective and safe for mobilizing CD34+ cells in donors for allogeneic hematopoietic stem cell transplantation. We conducted a retrospective case-matched design. A single dosage of 6 mg pegfilgrastim was used to mobilize PBPCs from 60 healthy donors. Granulocyte colony-stimulating factor (G-CSF, 10 μg/kg) was administered daily to the matched donors. Leukapheresis was scheduled to commence on day 4 of the mobilization regimen. The median yielded CD34+ cell in the pegfilgrastim group was higher than those in the G-CSF group, at 5.06 × 106/kg recipient weight. The 73.3% of donors mobilized with pegfilgrastim yielded >4 × 106 cells/kg CD34+ cells in a single apheresis procedure when compared to the 33.3% of donors mobilized with G-CSF (P < 0.001). The myeloid-derived suppressor cells (MDSC) proportion in the pegfilgrastim group was significantly higher than that in the G-CSF group (P < 0.001). The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was higher in the G-CSF group than that in the pegfilgrastim group (26.7% vs. 11.7%), without statistical difference. In comparison to the G-CSF group, the pegfilgrastim group had a reduced median pain intensity numerical rating scale score (1 vs. 2). A single 6 mg dosage of pegfilgrastim is effective and safe for allogeneic PBPCs collection from healthy donors. Pegfilgrastim may decrease the incidence of aGVHD by boosting MDSCs, which need further investigation.

Comparison of autologous, matched sibling, and alternative donor stem cell transplant outcomes for acute myeloid leukemia patients in first remission: A propensity score matching study.

Autologous hematopoietic stem cell transplantation (auto-HSCT), matched sibling donor HSCT (MSD-HSCT), and alternative donor HSCT (AD-HSCT) are viable post-remission treatment options for acute myeloid leukemia (AML). A total of 283 de novo favorable- and intermediate-risk AML patients, based on the ELN 2022 criteria, in first complete remission were initially included for propensity score matching. Following the matching process, 126 patients were selected for further analysis, with 42 patients in each of the auto-HSCT, MSD-HSCT, and AD-HSCT groups. Among the AD-HSCT group, 38 of 42 (90.5%) patients received haploidentical HSCT. In patients with persistent undetectable measurable residual disease (uMRD) before transplant (n=83), overall survival (OS) was similar across the groups. However, auto-HSCT showed a trend of increased disease-free survival (DFS) compared to AD-HSCT (HR 2.85, P=0.09), resulting in a 3-year DFS and OS of 79.1% and 82.8%, respectively. In the non-persistent uMRD group (n=38), auto-HSCT exhibited a tendency to increase the risk of relapse, particularly when compared to AD-HSCT (HR 0.24, P=0.07), but this did not result in inferior OS. The monthly direct medical cost per patient within the first 2years after HSCT was significantly lower in auto-HSCT compared to MSD-HSCT (P=0.015) and AD-HSCT (P<0.001). Our results provide evidence for the use of auto-HSCT as a viable therapeutic option for favorable- and intermediate-risk de novo AML patients in first complete remission with persistent uMRD. Additionally, our findings demonstrated a notable cost advantage associated with auto-HSCT compared to MSD-HSCT and AD-HSCT.

Characterization of 43 novel HLA-H alleles.

Forty-three novel HLA-H alleles, including 32 identified in cohorts of French donors for Hematopoietic Stem Cell Transplantation, have been characterized by Next-Generation Sequencing (NGS) using a long range PCR approach. A phylogenetic study confirms three main HLA-H clades.

Aortitis after administration of pegfilgrastim to a healthy donor for peripheral blood stem cell collection

A 45-year-old man who was a sibling donor for allogeneic peripheral blood stem cell transplantation (allo-PBSCT) was administered 7.2 mg of pegfilgrastim for stem cell collection. Peripheral blood stem cells were collected 4 days after administration of pegfilgrastim (Day 4) and 4.32 × 106 /kg of CD34-positive cells per recipient body weight were obtained. Fever of 38 ℃ or higher and left submandibular pain appeared on Day 6. Ultrasonography and contrast-enhanced computed tomography (CT) showed wall thickening of the carotid artery and the abdominal aorta. We carefully excluded the possibilities of cardiovascular and autoimmune diseases by thorough examination, and ultimately diagnosed pegfilgrastim-induced aortitis. The patient’s fever resolved rapidly after treatment with prednisolone (PSL) 1 mg/kg. We began to taper PSL after eight days. Sixty-one days after starting PSL, we confirmed that abdominal aortic wall thickening had improved by contrast-enhanced CT. We continued to taper off PSL and stopped 141 days later with no relapse thereafter. This is the first case report of pegfilgrastim-induced aortitis in an allo-PBSCT donor. Careful monitoring is warranted when administering pegfilgrastim to donors even without past medical history.

Joint models quantify associations between immune cell kinetics and allo-immunological events after allogeneic stem cell transplantation and subsequent donor lymphocyte infusion.

Alloreactive donor-derived T-cells play a pivotal role in alloimmune responses after allogeneic hematopoietic stem cell transplantation (alloSCT); both in the relapse-preventing Graft-versus-Leukemia (GvL) effect and the potentially lethal complication Graft-versus-Host-Disease (GvHD). The balance between GvL and GvHD can be shifted by removing T-cells via T-cell depletion (TCD) to reduce the risk of GvHD, and by introducing additional donor T-cells (donor lymphocyte infusions [DLI]) to boost the GvL effect. However, the association between T-cell kinetics and the occurrence of allo-immunological events has not been clearly demonstrated yet. Therefore, we investigated the complex associations between the T-cell kinetics and alloimmune responses in a cohort of 166 acute leukemia patients receiving alemtuzumab-based TCD alloSCT. Of these patients, 62 with an anticipated high risk of relapse were scheduled to receive a prophylactic DLI at 3 months after transplant. In this setting, we applied joint modelling which allowed us to better capture the complex interplay between DLI, T-cell kinetics, GvHD and relapse than traditional statistical methods. We demonstrate that DLI can induce detectable T-cell expansion, leading to an increase in total, CD4+ and CD8+ T-cell counts starting at 3 months after alloSCT. CD4+ T-cells showed the strongest association with the development of alloimmune responses: higher CD4 counts increased the risk of GvHD (hazard ratio 2.44, 95% confidence interval 1.45-4.12) and decreased the risk of relapse (hazard ratio 0.65, 95% confidence interval 0.45-0.92). Similar models showed that natural killer cells recovered rapidly after alloSCT and were associated with a lower risk of relapse (HR 0.62, 95%-CI 0.41-0.93). The results of this study advocate the use of joint models to further study immune cell kinetics in different settings.

CD3+TCRαβ/CD19+-Depleted Mismatched Family or Unrelated Donor Salvage Stem Cell Transplantation for Graft Dysfunction in Inborn Errors of Immunity

A minority of children experience significant graft dysfunction after an allogeneic hematopoietic stem cell transplant (HSCT) for inborn errors of immunity (IEI). The optimal approach to salvage HSCT is unclear with respect to conditioning regimen and stem cell source. This single-centre retrospective case series reports the outcomes of salvage CD3+TCRαβ/CD19 depleted mismatched family or unrelated donor stem cell transplantation (TCRαβ-SCT) between 2013 - 2022 for graft dysfunction in 12 children with IEI. Outcomes of interest were overall survival (OS), event free survival (EFS), graft-versus-host disease (GvHD)-free and event-free survival (GEFS), toxicities, GvHD, viremia and long-term graft function. A retrospective audit of patients who underwent second CD3+TCRαβ/CD19 depleted mismatched donor graft using Treosulfan-based reduced toxicity myeloablative conditioning. Median age at first HSCT was 8.76 months (range, 2.5 months - 6 years) and at second TCRαβ-SCT was 3.6 years (1.2 - 11 years). Median interval between first and second HSCT was 1.7 years (3 months - 9 years). The primary diagnoses were: severe combined immunodeficiency (SCID) (n=5) and non-SCID IEI (n=7). The indications for second HSCT were: primary aplasia (n=1), secondary autologous reconstitution (n=6), refractory aGVHD (n=3) and secondary leukemia (n=1). Donors were either haploidentical parental donors (n=10) or mismatched unrelated donors (n=2). All received TCRαβ/CD19-depleted-PBSC with a median CD34+ cell dose of 9.3 × 106/kg (2.8-32.3 × 106/kg) and a median TCRαβ+ cell dose of 4 × 104/kg (1.3-19.2 × 104/kg). All engrafted with median days to neutrophil and platelet recovery of 15 (12-24) and 12 (9-19). One developed secondary aplasia and one had secondary autologous reconstitution, but both underwent a successful third HSCT. Four (33%) had grade II aGvHD and none had grade III-IV aGvHD. None had cGvHD but one developed extensive cutaneous cGVHD after third HSCT using PBSC and ATG. Nine (75%) were noted to have at least one episode of blood viremia with HHV6 (n=6, 50%), adenovirus (n=6, 50%), EBV (n=3, 25%) or CMV (n=3; 25%). Median duration of follow-up was 2.3 years (range: 0.5 - 10 years) and the 2-year OS, EFS and GEFS were 100% (95% confidence interval, 0-100%), 73% (37-90%) and 73% (37%-90%) respectively. TCRαβ-SCT from mismatched family or unrelated donors, using a chemotherapy only regimen, is a safe alternative donor salvage transplant strategy for second HSCT in patients without a suitably matched donor.

Long-term follow-up of donor-derived CD7 CAR T-cell therapy in patients with T-cell acute lymphoblastic leukemia

BackgroundDonor-derived CD7-directed chimeric antigen receptor (CAR) T cells showed feasibility and early efficacy in patients with refractory or relapsed T-cell acute lymphoblastic leukemia (r/r T-ALL), in a previous phase I trial report, at a median follow-up of 6.3 months. Here we report long-term safety and activity of the therapy after a 2-year follow-up.MethodsParticipants received CD7-directed CAR T cells derived from prior stem cell transplantation (SCT) donors or from HLA-matched new donors after lymphodepletion. The target dose was 1 × 106 (± 30%) CAR T cells per kg of patient weight. The primary endpoint was safety with efficacy secondary. This report focuses on the long-term follow-up and discusses them in the context of previously reported early outcomes.ResultsTwenty participants were enrolled and received infusion with CD7 CAR T cells. After a median follow-up time of 27.0 (range, 24.0–29.3) months, the overall response rate and complete response rate were 95% (19/20 patients) and 85% (17/20 patients), respectively, and 35% (7/20) of patients proceeded to SCT. Six patients experienced disease relapse with a median time-to-relapse of 6 (range, 4.0–10.9) months, and 4 of these 6 patients were found to have lost CD7 expression on tumor cells. Progression-free survival (PFS) and overall survival (OS) rates 24 months after treatment were respectively 36.8% (95% CI, 13.8–59.8%) and 42.3% (95% CI, 18.8–65.8%), with median PFS and OS of respectively 11.0 (95% CI, 6.7–12.5) months and 18.3 (95% CI, 12.5–20.8) months. Previously reported short-term adverse events (< 30 days after treatment) included grade 3–4 cytokine release syndrome (CRS; 10%) and grade 1–2 graft-versus-host disease (GVHD; 60%). Serious adverse events reported > 30 days after treatment included five infections and one grade 4 intestinal GVHD. Despite good CD7 CAR T-cell persistence, non-CAR T and natural killer cells were predominantly CD7-negative and eventually returned to normal levels in about half of the participants.ConclusionsIn this 2-year follow-up analysis, donor-derived CD7 CAR T-cell treatment demonstrated durable efficacy in a subset of patients with r/r T-ALL. Disease relapse was the main cause of treatment failure, and severe infection was a noteworthy late-onset adverse event.Trial registrationChiCTR2000034762.

Autoimmune pathogenesis, immunosuppressive therapy and pharmacological mechanism in aplastic anemia.

Acquired aplastic anemia (AA) is an autoimmune disease of bone marrow failure mediated by abnormally activated T cells, manifested by severe depletion of hematopoietic stem and progenitor cells (HSPCs) and peripheral blood cells. Due to the limitation of donors for hematopoietic stem cell transplantation, immunosuppressive therapy (IST) is currently an effective first-line treatment. However, a significant proportion of AA patients remain ineligible for IST, relapse, and develop other hematologic malignancies, such as acute myeloid leukemia after IST. Therefore, it is important to elucidate the pathogenic mechanisms of AA and to identify treatable molecular targets, which is an attractive way to improve these outcomes. In this review, we summarize the immune-related pathogenesis of AA, pharmacological targets, and clinical effects of the current mainstream immunosuppressive agents. It provides new insight into the combination of immunosuppressive drugs with multiple targets, as well as the discovery of new druggable targets based on current intervention pathways.

Haploidentical vs. HLA-matched donor hematopoietic stem-cell transplantation for pediatric patients with acute lymphoblastic leukemia in second remission: A collaborative retrospective study of the Spanish Group for Bone Marrow Transplantation in Children (GETMON/GETH) and the Spanish Childhood Relapsed ALL Board (ReALLNet).

Studies addressing the role of haploidentical as alternative to HLA-matched donors for stem cell transplantation (SCT) often include patients with diverse hematological malignancies in different remission statuses. We compared outcomes of children with acute lymphoblastic leukemia (ALL) undergoing SCT in second complete remission (CR2) from haploidentical (n = 25) versus HLA-matched donor (n = 51). Patients were equally distributed across both groups according to age, immunophenotype, time to and site of relapse, relapse risk-group allocation, and minimal residual disease (MRD) before SCT. Incidence of graft failure, acute graft versus host disease (GVHD), and other early complications did not differ between both groups. We found no differences in overall survival (58.7% versus 59.5%; p = .8), leukemia free survival (LFS) (48% versus 36.4%; p = .5), event free survival (40% versus 34.4%; p = .69), cumulative incidence (CI) of subsequent relapse (28% versus 40.9%; p = .69), treatment related mortality (24% versus 23.6%; p = .83), CI of cGVHD (4.5% versus 18.7%; p = .2), and chronic GVHD-free and leukemia-free survival (44% versus 26.3%; p = .3) after haploidentical donor SCT. Chronic GVHD (HR = 0.09; p=.02) had protective impact, and MRD ≥ 0.01% before SCT (HR = 2.59; p=.01) had unfavorable impact on LFS. These results support the role of haploidentical donor SCT in children with ALL in CR2.

The effects of metamizole on hematopoietic progenitor cells: Suppression of hematopoiesis stimulation in vitro.

There is evidence that the adverse effects of metamizole occur due to the effect of the drug on the hematopoietic stem/progenitor cells, and therefore, the disruption of hematopoiesis. Therefore, our study aimed to evaluate the effects of metamizole on hematopoietic stem/progenitor cells using cell culture techniques. In our study, samples were taken from stem cell products of healthy allogeneic stem cell transplant donors. The colony-forming unit (CFU) assay was used for the cells obtained from these samples. In addition, the drug effects on cell proliferation were evaluated with the MTT. Furthermore, the cell colonies were labelled with immunofluorescent antibodies and the effects of metamizole on cell types formed in culture were evaluated. We determined that metamizole negatively affects the proliferation of cells, especially starting from 10 µM. As a result of the evaluation of colonization, we saw that the number of colonies decreased with increasing concentrations. Granulocyte-macrophage colonies were more affected at increasing concentrations than other colonies. As a result of the evaluations of our in vitro study, it was also shown as an important finding that the individual effects of the drug were highly variable. CFU method can be used as a suitable method to investigate the effects of drugs and toxic substances on hematopoiesis. We also think it may be suitable for pre-analysing hematopoietic side effects in new drug research. In addition, using stem cell samples in studies may contribute more easily to the in vitro simulation of hematopoietic differentiations (Fig. 7, Ref. 29). Text in PDF www.elis.sk Keywords: metamizole, hematopoietic progenitor cells, hematopoiesis, CFU assay, adverse effect.

Supporting family members requested to donate hematopoietic stem cells to a relative: development and pilot testing of a psycho-educational resource

Abstract Background: In light of the increased demand for related donors in allogeneic stem cell transplantation, recognition of the psychosocial issues has also emerged. While resources supporting unrelated volunteer donors exist, none address the emotional issues specific to being a related donor. Providing related donors with preparatory information could help improve the overall donation experience and donor's outcomes. Objective: The objectives of this study were to develop and pilot test a print-based psycho-educational resource to support donors in coping with the physical and emotional aspects of donating to a relative. This article describes the development and pilot testing of the resource. Methods: Seventeen related donors and eight transplant nurses and physicians (transplant professionals) completed a survey and provided quantitative and qualitative feedback on the acceptability of the resource and preferences regarding the ideal distribution time. Results: Respondents endorsed the resource and found it useful and appropriate for the information needs at different stages of the donation and transplant process. The most useful reported components of the resource were testimonials from previous donors and explanations of blood cancers and the stem cell donation process. Most donor respondents indicated that the resource should be distributed as soon as possible while transplant professionals felt this should be after tissue typing, once the donor is confirmed as suitable. Respondents requested additional information on the side effects of donating and the possibility of being asked to repeat donation if the recipient relapses. More donor testimonials were also desired. Conclusion: The resource appears to be acceptable to donors and transplant professionals and helpful for developing confidence about coping with the physical and emotional aspects of donation. Findings from this study are currently being used to further refine and deliver the resource in additional formats.

Allogenic matched sibling donor stem cell transplant in an adolescent refractory lymphoma – A case report

Allogenic matched sibling donor stem cell transplant in an adolescent refractory lymphoma – A case report

The effect of granulocyte colony stimulating factor on genotoxicity in allogeneic peripheral blood stem cell transplantation donors: a prospective case-control study.

Every year, thousands of donors are exposed to granulocyte-colony stimulating factor (G-CSF) for stem cell mobilization in hematopoietic stem cell transplantations (HSCT). Previous studies about the genotoxicity of G-CSF were inconclusive. In this study, the genotoxic effects of G-CSF in peripheral blood stem cell (PBSC) donors were evaluated prospectively by using three different validated and reliable methods for the first time in the literature to the best of our knowledge. Donors of PBSC transplantation (n=36), who received G-CSF were evaluated for genotoxicity by micronucleus test (MNT), nuclear division index (NDI), and comet assay (CA). Genotoxic effects are expected to cause an increase in MNT and CA values and decrease in NDI. Blood samples were collected at three timepoints (TP): before starting G-CSF (TP1), after G-CSF for five days (TP2), and one month after the last dose (TP3). Sixteen controls were included for baseline comparison of genotoxicity tests. CD34 cell counts and hemograms were also analyzed. MNT and CA parameters; comet and tail length, tail DNA%, and tail moment, showed no change in time whereas another CA parameter, Olive`s tail moment (OTM) was increased significantly at TP3 compared to both baseline and TP2 (p=0.002 and p=0.017, respectively). Nuclear division index decreased significantly at TP2 (p < 0.001), then increased above baseline at TP3 (p=0.004). Baseline comparison with controls showed higher MN frequency in donors without statistical significance (p=0.059). Whereas, CA results were significantly higher in controls. CD34 cell count showed moderate positive correlation with white blood cell count at TP2 (Pearson R=0.495, p=0.004). Our results showed the genotoxic effect of G-CSF in healthy donors, in two of the three tests performed, short-term effect in NDI, and long-lasting effect in OTM. So, this study provides novel information for the debate about the genotoxicity of G-CSF and supports the need for further studies with a larger sample size and longer follow-up.

Sex disparity in childhood cancer in India: a multi-centre, individual patient data analysis

Sex disparity and its determinants in childhood cancer in India remain unexplored, with scarce information available through summary statistics of cancer registries. This study analysed the degree of sex bias in childhood cancer in India and its clinical and demographical associations. In this retrospective, multicentre cohort study, we collected individual data of children (aged 0-19 years) with cancer extracted from the hospital-based records of three cancer centres in India between Jan 1, 2005, and Dec 31, 2019, and two population-based cancer registries (PBCRs; Delhi [between Jan 1, 2005, and Dec 31, 2014] and Madras Metropolitan Tumour Registry [between Jan 1, 2005, and Dec 31, 2017]). We extracted data on age, sex, and confirmed diagnosis of malignancy (according to the International Classification of Diseases-10 coding),and excluded participants if they were without a recorded diagnosis, had a benign diagnosis, had missing sex information, resided outside of India, or were a donor for haematopoietic stem cell transplantation (HSCT). The primary outcome was the male-to-female incidence rate ratio (MF-IRR) in the two PBCRs and the male-to-female ratios (MFR) from the hospital-based and the HSCT data. For PBCR data, MF-IRR was estimated by dividing the MFR by the total population at risk. MFR was analysed for patients seeking treatment at the cancer centres and for those undergoing HSCT. Logistic regression analyses were done to explore the association of clinical and demographical variables with sex of the patients seeking treatment and those undergoing HSCT in hospital-based data and multivariable analyses were done to determine independent sociodemographic predictors of sex bias. Annual time trends of MFR and MF-IRR during the 15-year study period were ascertained by time series regression analyses. We included 11 375 children from PBCRs in the study. 26 891 children from hospital-based records were screened, and data from 22 893 (85·1%) were included (including 514 who underwent HSCT). Residence details were missing for 257 (1·1%) of 22 893 patients from hospital-based records. The crude MFR of children at diagnosis was in favour of boys: 2·00 (95% CI 1·92-2·09) in the Delhi PBCR and 1·44 (1·32-1·57) in Madras Metropolitan Tumour Registry. The MF-IRRs for cancer diagnosis were also skewed in favour of boys in both PBCRs (Delhi 1·69 [95% CI 1·61-1·76]; Madras Metropolitan Tumour Registry 1·37 [1·26-1·49]). The MFR for children seeking treatment from hospital-based records was 2·06 (95% CI 2·00-2·12) in favour of boys. In subgroup analyses, the proportion of boys seeking treatment was higher in northern India than southern India (p<0·0001); in private centres than in centres providing subsidised treatment (p<0·0001); in patients with haematological malignancies than those with solid malignancies (p<0·0001); in those residing 100 km or further from the hospital than those within 100 km of a hospital (p<0·0001); and those living in rural areas than those living in urban areas (p=0·0006). The MFR of 514 children who underwent HSCT was 2·81 (95% CI 2·32-3·43) in favour of boys. Time trend analysis showed that MFR did not show any significant annual change in either the overall cohort or in any of the individual centres for hospital-based data; however, the analysis did show a declining MF-IRR in the Delhi PBCR from 2005 to 2014 (p=0·031). The sex ratio for childhood cancer in India has a bias towards boys at the level of diagnosis, which is more pronounced in northern India and in situations demanding greater financial commitment. Addressing societal sex bias and enhancing affordable health care for girls should be pursued simultaneously in India. None. For the Hindi translation of the abstract see Supplementary Materials section.

CD84: A Novel Target for CAR T-Cell Therapy for Acute Myeloid Leukemia

Relapsed or refractory acute myeloid leukemia (AML) patients have scarce treatment options despite the recent emergence of novel targeted therapies. Chimeric antigen receptor (CAR) T-cell therapies have been approved for the treatment of B-cell malignancies and multiple myeloma, but it remains very challenging to treat myeloid malignancies with this therapeutic modality, in part due to the absence of specific tumor antigens in these indications. Antigens expressed on AML cells are usually shared with healthy hematopoietic stem/progenitor cells (HSPC) and targeting them can lead to life-threatening on-target/off-tumor toxicity. CD84 antigen is an immunoreceptor member of the SLAM family (SLAMF5), whose expression has been reported in certain immune cells and in B-cell malignancies. In this study, we show for the first time that CD84 is overexpressed in AML and present the first results of CD84-targeting CAR T-cells for the treatment of this disease. We analyzed AML primary samples and found that CD84 is overexpressed on the surface of AML cells, both de novo and at relapse, while lower expression was detected in CD34+ HSPC. Furthermore, immunohistochemistry analysis of healthy human tissues showed that CD84 is not expressed in the parenchyma of liver, kidney, lung, myocardium, skin, or brain (cerebral cortex and cerebellum), although expression was detected in tissue monocytes/macrophages. This expression pattern is similar to that of CD123, a clinical stage and safe CAR T target in AML. Anti-CD84 CAR T cells were engineered using both fully human and murine CD84-binding sequences. The sequences of the variable regions of the light (VL) and the heavy (VH) chain were used to design different single-chain variable fragments (scFv), changing the order (VLVH or vice versa) and the linker length. In total, we designed 21 lentiviral second-generation CARs with an anti-CD84 scFv, a CD8α hinge and transmembrane domain, a 4-1BB costimulatory and a CD3ζ signaling domain. Some constructs were discarded due to failed lentiviral transduction or target recognition; the following CAR T-cells were characterized in depth: one with a fully human scFv, CD84.01 (VHVL), and 5 with different murine scFv, CD84.02 (VLVH), CD84.03 (VHVL), CD84.04 (VHVL), CD84.05 (VHVL), and CD84.06 (VHVL). All these CAR T-cells displayed cytotoxic activity towards, and were able to proliferate and secrete cytokines in vitro when exposed to the CD84high Kasumi-1 and the CD84low U937 AML cell lines (Figure 1A). We then analyzed their cytotoxicity against monocytes, B cells and T cells purified from the same donor as the CD84 CAR T cells were generated; all CART cells exerted some cytotoxic activity against their own T cells, which was much lower than that against Kasumi-1 cells. To assess the myeloablative potential of CD84 CAR T cells, we carried out cytotoxic assays against CD34+ HSPCs purified from 1) donor cord blood; 2) directly from donor bone marrow samples, or 3) an apheresis product of a donor for an allogeneic hematopoietic stem cell transplant. We found that the cytotoxic effect against CD34+ HSPC was much lower than that against leukemic cells. Based on these in vitro results, the CARTs CD84.02 and CD84.03 were tested for their efficacy in a human NSG xenograft mouse model of AML (Kasumi-1). Although CD84.02 appeared to be more effective than CD84.03, both were able to control the disease for at least 43 days (Figure 1B), at which point no leukemic cells were detected in the bone marrow and spleen of CAR T-treated animals. In contrast, CD84 CAR T cells were found in these organs at the end of the experiment. In summary, here we report that CART cells directed against CD84 can eliminate AML cells both in vitro and in vivo. Our data support the therapeutic use of CD84 CAR T cells for relapsed/refractory (R/R) AML. However, due to its potential myelotoxicity, we encourage its first use in a clinical trial as a bridge therapy to allogeneic stem cell transplant for patients with R/R AML. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Prep@Gref: Software Streamlining for the Search for Donors for Hematopoietic Stem Cell Transplantation

Introduction: Donor recruitment in allogeneic hematopoietic stem cell transplantation (HSCT) is a multi-step process involving several stakeholders: patients, donors, coordinators, clinicians, HLA typing lab and blood collection center. With few, if any software existing on the market to perform these steps securely and efficiently, we aimed at developing an in-house academic software to streamline this process. Our objectives were: to reduce delays, facilitate interactions between stakeholders through secure real-time sharing of information and documents and limit the workload at each step. Methods: We set off by listing the steps involved in donor recruitment, analyzing their outputs and time required to accomplish them, documenting the delays between them and establishing key performance indicators. We then created the Prep@gref software that includes an interactive list of patients awaiting an allogenic HSCT, with work lists specific to each of the previously-listed steps (updated in real time), documents and information necessary for proceeding (or not) with donor recruitment and automated alerts for deadlines to accomplishing the individual tasks by each stakeholder. Training stakeholders and optimizing the software preceded its introduction into routine practices. Measurable outcomes were: median time to donor identification (related and unrelated donors), non-quantifiable variables include: stakeholder feedback and ease-of-use of the software. Results: Tracking key performance indicators shows that the time for matched related donor (MRD) identification has reduced by a median of 29% over the past 5 years: 34 days pre-Prep@gref to 24 days since the introduction of Prep@gref into routine use. Time for mismatch related donor (MMRD) has reduced by a median of 32% (36 days pre-Prep@gref versus 25 days post). Unrelated donor search reduced by 21% (67 days versus 53 days, respectively). Time for adoption of the software by stakeholders could explain the slow amelioration of indicators over time. Increase in activity of the transplant program (21% since the introduction of Prep@gref into routine use) and the COVID-19 pandemic did not significantly affect the time for donor identification. Positive feedback from clinicians and coordinators favor its positive impact on practices. Conclusion: Prep@gref software represents a prototype of complex care process modeling, evolving from the traditional organizational set up in many hospitals for donor recruitment. Saving times and being able to delegate tasks is key in addressing shortage of human resource that periodically happen in our activities, while absorbing the growing workload and increasing complexities of these tasks.

Haploidentical Donor Vs. Mismatch Unrelated Donor in Reduced Intensity Conditioning Transplant: A Study from the Spanish Group of Hematopoietic Transplant and Cell Therapy (GETH-TC)

The most suitable donor for allogeneic stem cell transplant is still a matter for debate when there is no matched related or unrelated donor. In this setting, information comparing MMURD vs. HAPLO remains scarce and do not show differences between both sources (Piemontese, S et al., Hematol Oncol. 2017; Shem-Tov N et al., Leukemia 2020; Battipaglia G et al., BMT 2022). This study analyzes the outcomes of HAPLO vs. MMURD stem cell transplant recipients in reduced intensity conditioning scenarios (allo-RIC) in a retrospective analysis from the GETH-TC study group. Methods: Consecutive patients receiving a first allo-RIC between 1/2012 and 3/2021 at 9 GETH/EBMT centers with HAPLO or MMURD (mismatch at HLA-A, B, C, or DRB1 by molecular techniques) were included. Patients undergoing HAPLO received post-transplant cyclophosphamide (PTCY) based graft vs. host disease (GVHD) prophylaxis associated with rapamycin, tacrolimus, or cyclosporine, +/- mycophenolate. For MMURD, prophylaxis was diverse, including PTCY. Baseline characteristics and outcomes were compared according to the donor type through logistic regression. To balance the two groups, the Propensity Score Weighting method was performed with the variables that were significant in the logistic regression. Survival was calculated using the Kaplan-Meier method and the HR using the Cox model. The primary objective was the comparison of the aGVHD III-IV or severe chronic GVHD-free/relapse-free survival (GRFS). Secondary endpoints were overall survival (OS), relapse/progression-free survival (DFS), non-relapse-related mortality (NRM), relapse, and acute and chronic GVHD. Results: A total of 411 patients were included, 287 HAPLO and 124 MMURD (Table 1), with a median follow-up of 46.1 and 48.2 months, respectively. The GRFS at 24 months was similar in both groups, 48.5% vs. 53.9% in HAPLO and MMURD, respectively [HR 0.9, P=0.79). There were no differences in 2 year-OS 58.9% vs. 60.7% (HR 1.04, P=0.93), or in 2-year DFS 55.1% vs. 55.8% (HR 1.05, P=0.9). Similarly, NRM (32.3% vs. 32.1% (HR 1.09, P=0.85) and relapse (18.6% vs. 17.9% (HR 0.96 [95%CI 0.31;2.96] P=0.94) did not present statistically significant differences between HAPLO and MMURD. In addition, there was no difference between groups in time to neutrophil (19 days [95%CI 18;20] HAPLO vs 18 days [95%CI 15;19] MMURD, P= 0.08) and platelet engraftment (27 days [95%CI 23;29] HAPLO vs 20 days [95%CI 13; 33] MMURD, P= 0.15). Regarding 2-4 acute GVHD, the incidence at 6 months was 51.7% vs. 63.2% in the HAPLO vs. MMURD recipients (HR 1.44 [95%CI 0.8; 2.6], P=0.23), without significant differences in 3-4 acute GVHD grade. Seventy-seven HAPLO patients and 42 MMURD patients developed global chronic GVHD, with no significant differences in incidence between groups. Remarkably, MMURD (1% [95%CI 0; 2.6]) had lower incidence of severe forms of chronic GVHD than HAPLO (6.7% [95%CI 2.5; 10.6]) (HR 0.11 95%CI [0.02;0.57], P=0.01). When the analysis was restricted to PTCY-based prophylaxis patients (48 MMURD vs. 287 HAPLO), the outcomes were similar, with a significantly lower incidence of severe forms of chronic GVHD in the MMURD group. Finally, events defining GRSF were similarly distributed between both groups (Figure 1), except for chronic GVHD. However, the latter had a low incidence in both groups, so this difference did not impact the primary endpoint. Conclusion: In this cohort of patients, no differences in terms of OS, DFS, NRM, relapse, or GRSF were observed between HAPLO and MMURD. Transplantation with MMURD was associated with less severe chronic GVHD, even when considering the group of patients with PTCY prophylaxis exclusively. This advantage of MMURD compared to HAPLO is not translated into an improvement on the GRFS. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal