[Pathogenesis and novel therapies for chronic GVHD].

Treatment for chronic graft-versus-host disease, the most important long-term complication of allogeneic hematopoietic cell transplantation, has changed significantly over the past decade. Development of novel targeted therapies has advanced as objective criteria for the diagnosis and evaluation of chronic GVHD have been established and understanding of the biological pathways to pathogenesis has increased. This paradigm shift is driving chronic GVHD practice significantly toward individualized therapy while minimizing exposure to steroids. Treatment using a variety of novel agents, tailored to each individual patient's condition, is expected to improve quality of life and overall survival by preventing chronic GVHD, controlling disease progression, and maintaining motor and occupational functions. This article reviews the pathogenesis of chronic GVHD and discusses prospects for the treatment of chronic GVHD, along with recently approved drugs and promising drugs in development.

[Allogeneic transplantation as a therapeutic option for atypical chronic myeloid leukemia].

Atypical chronic myeloid leukemia (aCML) is a rare disease classified as a myelodysplastic/myeloproliferative neoplasm (MDS/MPN). Recent advances in gene mutational profiling have clarified the characteristics of aCML as a disease entity relative to other MDS/MPNs. Although some studies suggest the efficacy of DNA demethylating agents and tyrosine kinase inhibitors, data about these agents are limited due to the small number of patients. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is only therapeutic option that can provide durable remission for aCML and other MDS/MPNs. Retrospective studies from Europe and Japan revealed the clinical results of allo-HSCT for aCML. This review summarizes the pathogenesis of aCML and the development of allo-HSCT and other therapeutic options.

Long-Term Survival and Immune Reconstitution of Donor-Derived Chimeric Antigen Receptor T-Cell Therapy for Childhood Molecular Relapse of B-Cell Acute Lymphoblastic Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation.

Measurable residual disease (MRD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an independent risk factor for relapse in patients with acute lymphoblastic leukemia (ALL). This study aimed to assess the efficacy, safety, and immune reconstitution of chimeric antigen receptor T-cell (CAR-T) therapy in patients with molecular relapse after allo-HSCT. Eleven patients with molecular relapse of B-cell-ALL who underwent CAR-T therapy after allo-HSCT were enrolled. The rate of MRD negativity after a month of CAR-T infusion was 81.8%. Patients who bridged to second-HSCT after CAR-T therapy (n = 3) showed a trend of higher 3-year leukemia-free survival and 3-year overall survival than those who did not (n = 8; 100% vs. 75.0%; 95% CI, 45.0-104.9%; p = 0.370). No treatment-related mortalities were observed. Among patients who did not bridge to second-HSCT and remained in complete remission until the last follow-up (n = 6), five of them had not recovered normal immunoglobulin concentrations with a median follow-up of 43 months. CAR-T therapy may be a safe and effective treatment strategy to improve survival after allo-HSCT; however, the problem of prolonged hypogammaglobulinemia in patients who do not bridge to second-HSCT is worth noting.

Insights into cytomegalovirus-associated T cell receptors in recipients following allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Cytomegalovirus (CMV) reactivation is a serious problem in recipients of allogeneic hematopoietic stem cell transplantation. Long-term latency depends on specific T cell immune reconstitution, which identifies various pathogens by T cell receptors (TCRs). However, the mechanisms underlying the selection of CMV-specific TCRs in recipients after transplantation remain unclear. METHODS: Using high-throughput sequencing and bioinformatics analysis, the T cell immune repertoire of seven CMV reactivated recipients (CRRs) were analyzed and compared to those of seven CMV non-activated recipients (CNRs) at an early stage after transplant. RESULTS: The counts of unique complementarity-determining region 3 (CDR3) were significantly higher in CNRs than in CRRs. The CDR3 clones in the CNRs exhibit higher homogeneity compared to the CRRs. With regard to T cell receptor ß-chain variable region (TRBV) and joint region (TRBJ) genotypes, significant differences were observed in the frequencies of TRBV6, BV23, and BV7-8 between the two groups. In addition to TRBV29-1/BJ1-2, TRBV2/BJ2-2, and TRBV12-4/BJ1-5, 11 V-J combinations had significantly different expression levels between CRRs and CNRs. CONCLUSIONS: The differences in TCR diversity, TRBV segments, and TRBV-BJ combinations observed between CNRs and CRRs might be associated with post-transplant CMV reactivation and could serve as a foundation for further research.

Superior survival after unrelated allogeneic stem cell transplantation with low-dose ATG compared to low-dose TBI in myeloablative fludarabine/busulfan-based regimen for MDS on behalf of the adult MDS Working Group of the JSTCT.

The fludarabine/intravenous busulfan 12.8 mg/kg (FB4) regimen is an effective conditioning regimen in allogeneic hematopoietic stem cell transplantation for myelodysplastic syndrome (MDS); however, limited data is available on the prognostic impact of FB4 with low-dose anti-thymoglobulin (ATG ≤ 5 mg/kg) or low-dose total body irradiation (TBI ≤ 4 Gy). Therefore, we retrospectively evaluated the outcomes in 280 adults with de novo MDS who underwent their first transplantation from an unrelated donor between 2009 and 2018. Median age was 61 years (range, 16 to 70 years). In the FB4 alone (FB4), FB4 plus ATG (FB4-ATG), and FB4 plus TBI (FB4-TBI) groups, 3-year overall survival (OS) rates were 39.9, 64.8, and 43.7 %; 3-year non-relapse mortality (NRM) were 32.1, 22.1, and 27.1%; and 3-year relapse incidences were 34.7, 21.2, and 28.9%, respectively. The multivariate analyses showed that FB4-ATG group significantly correlated with better OS (hazard Ratio [HR], 0.51; 95% confidence interval [CI], 0.27-0.95; P=0.032) than FB4 group. FB4-ATG group tended to correlate with lower NRM (HR, 0.36;95% CI, 0.13-1.06; P=0.063) than FB4 group. In comparison with FB4-TBI group, FB4-ATG group showed better OS (HR 0.52, 95% CI 0.27-0.99, P=0.049) and NRM (HR 0.034, 95% CI 0.11-0.92, P=0.034). No significant differences were observed in OS and NRM between the FB4-TBI and FB4 groups. The present study demonstrated that the FB4 plus low-dose ATG regimen improved OS and NRM, but FB4 plus low-dose TBI regimen had no clear benefit over FB4 alone, in MDS patients who used unrelated donors.

Chemotherapy and allo-HSCT for young patients with aggressive ATL.

Adult T-cell leukemia-lymphoma (ATL) is an aggressive malignancy with a poor prognosis, especially for patients with the aggressive subtype. While conventional chemotherapy offers short-term disease control, allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the most promising curative approach for young, transplant-eligible patients. This review focuses on current treatment strategies for aggressive ATL in this specific population. We discuss the rationale for early upfront allo-HSCT following induction chemotherapy. The advent of allo-HSCT using alternative donors, particularly haploidentical HCT, has broadened the applicability of early upfront allo-HSCT in patients with aggressive ATL worldwide. Finally, we address emerging therapies that may improve outcomes in the context of allo-HSCT, paving the way for further advancements in the treatment of aggressive ATL.

Allogeneic transplantation for adult T-cell leukemia/lymphoma in adolescent and young adults and young patients: A nationwide retrospective study by the ATL working group of the Japan society for transplantation and cellular therapy.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) provides durable remission for patients with adult T-cell leukemia/lymphoma (ATL); however, few studies have focused on post-transplant outcomes in ATL patients ≤49 years. To clarify prognostic factors in ATL among patients <40 years (adolescents and young adult [AYA]; n = 73) and 40-49 years (Young; n = 330), we conducted a nationwide retrospective study. Estimated 3-year overall survival (OS) rates were 61.8% and 43.1% in AYA and Young patients, respectively (p = 0.005). In the multivariate analysis, Young patients showed worse OS (Hazard ratio (HR) [95% confidential interval] 1.62 [1.10-2.39], p = 0.015), chronic graft-versus-host disease (GVHD)-free and relapse-free survival (CRFS) (HR 1.54 [1.10-2.14], p = 0.011), and GVHD-free and relapse-free survival (GRFS) (HR 1.40 [1.04-1.88], p = 0.026) than AYA patients. No significant differences were observed in OS, CRFS, or GRFS between the myeloablative conditioning (MAC) and reduced-intensity conditioning (RIC) regimens; however, non-relapse mortality was significantly lower in patients with the RIC regimen than those with the MAC regimen (HR 0.46 [0.24-0.86], p = 0.015). In summary, OS was worse in Young patients than in AYA patients in the allo-HSCT setting for ATL. Furthermore, the RIC regimen has potential as an alternative treatment option for ATL patients ≤49 years.

Inflammation Decreases Ciclosporin Metabolism in Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Graft-versus-host disease (GVHd) remains a significant challenge following allogeneic hematopoietic stem cell transplantation (HSCT). Prevention of GVHd relies mainly on the use of calcineurin inhibitors, notably ciclosporin that exhibits complex pharmacokinetics influenced by many factors including drug-drug interactions (DDIs). Due to the downregulation of drug metabolizing enzymes and transporters, it has been postulated that inflammation may be a contributing factor to the variability observed in ciclosporin pharmacokinetics. This study aimed to assess the impact of inflammation, as indicated by C-reactive protein (CRP) levels, on the metabolism of ciclosporin in adult allogeneic HSCT recipients. A retrospective observational study was conducted at Rennes University Hospital involving 71 adult HSCT patients. The relationship between the intensity of inflammation (no-to-mild, moderate, and severe), and the metabolism of ciclosporin (estimated by the concentration/dose ratio) was assessed. Severe inflammation significantly decreased the metabolism of ciclosporin, as evidenced by higher concentration/dose ratios. Thanks to the daily dose adjustment, inflammation did not influence the blood levels of ciclosporin. Interestingly, DDIs did not emerge as a significant covariate in influencing ciclosporin metabolism. This is likely because the CYP3A4 inhibitory potential of interacting drugs may be masked in HSCT patients where metabolism is already upstream downregulated by inflammation. The study highlights the intricate relationship between inflammation and ciclosporin pharmacokinetics in HSCT patients. This underscores the necessity for therapeutic monitoring and the potential adjustment of dosage strategies based on the inflammatory status. These insights could contribute to the development of more personalized, optimized, and effective management strategies for HSCT recipients.

Healthcare resource utilization and associated costs in patients with chronic graft-versus-host disease post allogeneic hematopoietic stem cell transplantation in England: HCRU and associated costs in patients with cGvHD in England.

BACKGROUND: Limited evidence suggests chronic graft-versus-host disease (cGvHD) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) increases healthcare resource utilization (HCRU) and costs. However, this burden has not been well characterized in England. OBJECTIVE: This study assesses secondary care HCRU and costs for patients following allo HSCT in England with cGvHD and patients who did not develop graft versus-host disease (GvHD). Further stratification was performed among patients who did or did not subsequently receive high-cost therapies for the treatment of cGvHD. STUDY DESIGN: This descriptive, retrospective cohort study used Hospital Episode Statistics (HES) data from April 2017-March 2022. HES data captures information on reimbursed diagnoses and procedures from all National Health Service (NHS) secondary care admissions and attendances in England. High-cost drugs as defined by NHS England are recorded in HES, these drugs and other procedures including plasma exchange, were used to identify patients with cGvHD who were in receipt of high-cost therapies. HCRU and costs were described for patients with cGvHD following allo-HSCT (n=721) and were matched with patients with no evidence of GvHD following allo-HSCT (n=718). HCRU and costs were also described for the subset of patients with cGvHD (n=198) following receipt of high-cost therapies and patients with cGvHD prior to or without such therapies (n=523). RESULTS: A higher proportion of patients with cGvHD had at least one inpatient or intensive care unit (ICU) admission or emergency care attendance than patients without GvHD (inpatient: 74.6% vs 66.6%; emergency care: 39.3% vs 30.5%; ICU: 7.4% vs 4.7%; respectively); whilst the proportion of patients with an outpatient attendance were similar for both groups (outpatient: 80.3% vs 84.1%; respectively). The cost across all secondary care settings was higher for patients with cGvHD than patients without GvHD, with a mean cost of inpatient admissions of £17,339 ppy for those with cGvHD vs £8,548 ppy in patients without GvHD. A higher proportion of patients who received high-cost therapies for the treatment of cGvHD had at least one secondary care admission or attendance, than patients who did not (inpatient: 85.4% vs 66.4%; ICU: 7.1% vs 5.4%; outpatient: 87.9% vs 76.7%; emergency care: 44.4% vs 36.5%; respectively). Patients who were treated with high-cost therapies for the treatment of cGvHD had a greater mean number (14.6 vs 8.2 ppy, respectively) for all-cause inpatient admissions after treatment, than patients who did not. In all secondary care settings, the total cost ppy was higher for patients who received high-cost therapies for the treatment of cGvHD, than for those who did not. Patients who were treated with high-cost therapies for the treatment of cGvHD had a greater mean cost (£21,137 vs £15,956 ppy, respectively) for all-cause inpatient admissions than patients who did not. CONCLUSIONS: This study demonstrates that cGvHD and the use of associated high-cost therapies impacts healthcare activity and costs across various secondary care settings in England more than patients without GvHD and patients with cGvHD who received no high-cost therapies.

Measurable residual disease assessment prior to allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia and myelodysplastic syndromes: a 20-year monocentric study.

Patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) who undergo allogeneic hematopoietic stem-cell transplantation (alloHSCT) can have divergent survival outcomes while all in morphological complete remission (CR). Techniques of measurable residual disease (MRD) have allowed us to refine their prognosis in two categories: MRD-positive and MRD-negative patients. We conducted a monocentric retrospective study (01/2000-12/2020) to assess the prognosis of pretransplant MRD status measured by multiparametric flow cytometry (MFC) and molecular biology assessed by PCR. 192 patients were included. The median follow-up period was 77 months. Among patients undergoing alloHSCT in CR, overall survival (median-OS: 130.6 vs. 16.0 months, P < 0.001), disease-free survival (median-DFS: 109.6 vs. 7.1 months, P < 0.001) and cumulative incidence of relapse (12-month CIR: 7.3% vs. 33.7%, P < 0.0001) were significantly different between MRD-negative and MRD-positive patients. Patients with discordant intermethod results had intermediate DFS. MRD-negative patients according to molecular PCR-based techniques, WT1 overexpression and MFC had longer median-DFS, compared to MRD-positive patients (P = 0.001, P < 0.001, P < 0.001, respectively). Looking into subgroups, MRD-positive patients among the ELN2017 adverse-category (P < 0.0001), myeloablative and reduced-intensity conditioning regimens (P < 0.0001, P = 0.005), < 60-year patients (P < 0.001) and AML patients (P < 0.001) were associated with lower DFS. This difference was not found in ≥ 60-year patients (P = 0.27) and MDS patients (P = 0.70). MRD-positive patients within the favorable/intermediate ELN2017 category trended toward lower DFS (P = 0.05). We confirmed that MRD status prior to alloHSCT is a strong prognostic factor for OS, DFS and CIR. Combining MFC and molecular-PCR techniques to assess MRD seems primordial as inter-method discordance can be consequential.

Pre-engraftment bacteremia after allogeneic hematopoietic cell transplantation without primary fluoroquinolone antibacterial prophylaxis.

BACKGROUND: Bacteremia is a common complication in allogeneic hematopoietic cell transplant recipients (alloHCTr), especially during the pre-engraftment period. International guidelines recommend antibacterial prophylaxis (ABP), despite potential selection for multidrug-resistant organisms (MDRO). Limited contemporary data exist on the epidemiology of pre-engraftment bacteremia in alloHCTr, who do not receive ABP. METHODS: We performed a retrospective observational single-center cohort study including all consecutive adult alloHCTr (2015-2021), investigating the incidence, risk factors, and outcomes of bacteremia during the engraftment period. Primary fluoroquinolone (FQ) ABP is not routinely administered in our center. RESULTS: Among 421 patients identified, 124 bacteremia episodes were observed in 121/421 (29%) alloHCTr. The median time to the 1st bacteremia episode was 9 days (IQR 6-11). Most (105/124, 85%) episodes were monomicrobial, while >1 pathogens were identified in 19/124 (15%) episodes. Overall, 152 pathogens were isolated, with a predominance of Gram-positive (118/152, 78%), including coagulase-negative staphylococci (n:47), streptococci (n:46), and enterococci (n:15), followed by Gram-negative bacteria (GNB, 30/152, 20%), and anaerobes (4/152, 3%). There were 2/152 (1%) MDRO (extended-spectrum beta-lactamase producing) GNB. Multivariable analyses identified age >40-year-old (OR 2.4, P = 0.02), male gender (OR 1.8, P = 0.02), and a haploidentical/mismatched unrelated donor (OR 2.5, P < 0.001) as independent risk factors for bacteremia. All cause 30-day mortality among alloHCTr with bacteremia was 0.8% (1/121): one patient died due to an HCT-related complication. CONCLUSION: Despite lack of primary FQ ABP, low rates of bacteremia were observed during the pre-engraftment period, with low MDRO prevalence and mortality. Our findings may allow to revisit the need for primary universal FQ ABP in high-risk neutropenic hematology patients.

[Analysis of the therapeutic effect of avatinib bridged allogeneic hematopoietic stem cell transplantation on 7 cases of recurrent/refractory RUNX1-RUNX1T1 positive acute myeloid leukemia with KIT mutations].

Objective: To evaluate the efficacy of avatinib plus allogeneic hematopoietic stem cell transplantation (allo-HSCT) for the treatment of recurrent/refractory RUNX1-RUNX1T1 positive acute myeloid leukemia (AML) with KIT mutations. Method: A retrospective study was conducted on the clinical data of seven relapsed/refractory AML patients containing the RUNX1-RUNX1T1 fusion gene and KIT mutation who received afatinib plus allo-HSCT treatment at the First Affiliated Hospital of Soochow University from June 2019 to June 2023. Results: The seven AML patients included one male and six females with a median age of 37 (18-56) years. All seven patients had KIT mutations (five positive for D816V and two positive for D816Y) . There were two refractory patients and five relapsed patients (all of whom had bone marrow recurrence) . All patients had to complete at least one course of treatment with afatinib before transplantation. Four patients achieved complete remission (CR) after treatment with afatinib, six patients had negative KIT gene mutations, and one had a decreased KIT gene mutational burden. There were three cases of unrelated identical transplantation and four cases of haploidentical transplantation. All patients received the modified Bu/Cy pretreatment regimen. After transplantation, all patients were successfully implanted and a bone marrow examination showed CR and minimal residual disease turned negative. Five patients exhibited negative fusion genes. Two patients died from infection following transplantation. Conclusion: Afatinib plus allo-HSCT may be an effective and safe new treatment strategy for RUNX1-RUNX1T1 positive AML patients with KIT-D816 mutation.

Successful Cord Blood Transplantation for Myeloid/Natural Killer Precursor Acute Leukemia: A Case Report and Literature Review.

A 21-year-old man was diagnosed with myeloid/natural killer precursor leukemia (MNKPL) with bone marrow infiltration of blasts of cyCD3+, CD7+, CD33+, CD34dim, CD56+/-, HLA-DR+, cyMPO+, and TdT- immunophenotypes. Although hyper-CVAD therapy was unsuccessful, induction treatment with idarubicin and cytarabine resulted in complete remission (CR). The patient subsequently underwent cord blood transplantation with a myeloablative conditioning regimen, which resulted in durable CR and complete donor chimerism. He had been in good health without relapse for over nine months since transplantation. Timely allogeneic hematopoietic stem cell transplantation using an available donor source may be a promising treatment strategy for MNKPL.

TBI/Cy followed by auto-HSCT is a good choice next to allo-HSCT for patients with T-LBL/ALL.

The aim of this retrospective study was to evaluate the efficiency and safety of total body irradiation plus cyclophosphamide (TBI/Cy) followed by autogenetic hematopoietic stem cell transplantation (auto-HSCT) in T-LBL/ALL patients that cannot receive allogeneic hematopoietic stem cell transplant (allo-HSCT). Between 2013 and 2023, 24 patients received auto-HSCT following by TBI/Cy, 26 patients underwent allo-HSCT, all patients achieved completed hematopoietic reconstitution after HSCT. The progression free survival (PFS) and overall survival (OS) had no statistically significant differences between the two groups (P = 0.791, HR 1.127, 95%CI 0.456-2.785; P = 0.456, HR 0.685, 95%CI 0.256-1.828). Although the cumulative incidence of relapse was lower for patients who received allo-HSCT than auto-HSCT (P = 0.033, HR 3.707, 95%CI 1.188-11.570, 2-year relapse 11.5% vs. 33.3%), the incidence of non-relapse mortality (NRM) was higher than that in the auto-HSCT group (P = 0.014, HR 0.000, 95%CI -1.000 - -1.000, 2-year NRM, 23.1% vs. 0%). Trough Landmark analysis, the two groups showed a statistically significant difference in 3-year PFS and 4-year OS curves (Figure S2A&B, P = 0.039, HR 0.426, 95%CI 0.163-1.117; P = 0.014, HR 0.317, 95%CI 0.113-0.887). By COX analysis, poor baseline performance status (ECOG-PS ≥ 2) and CNS involvement were risk factors for PFS and OS. In conclusion, TBI/Cy followed by auto-HSCT is a good choice next to allo-HSCT for patients with T-LBL/ALL.

A limited sampling model to estimate the area under the curve of mycophenolic acid in hematopoietic stem cell transplantation recipients.

Relationship between the areas under the curve (AUC) of mycophenolic acid (MPA) and the likelihood of rejection is well-established in solid organ transplantation recipients. In hematopoietic stem cell transplantation (HSCT), MPA AUC is also linked to graft versus host disease. This study aimed to develop a simplified method to estimate MPA AUC0-12 in Chinese patients undergoing allogeneic HSCT (allo-HSCT). Intensive sampling was conducted in 22 patients who were orally administered mycophenolate mofetil. Plasma concentrations of total MPA were measured, and a model predicting AUC0-12 using data from these 22 patients was constructed through regression analysis. The accuracy of the most suitable model was assessed in an additional 20 patients. None of the individual MPA concentrations showed a strong correlation with AUC0-12 (r2 < 0.7). Models utilizing 4 or more concentrations were found to effectively estimate MPA AUC0-12 (r2 > 0.87). The most operationally feasible model demonstrated good predictive performance with a mean absolute percentage error (APE%) < 20%. Single MPA concentrations showed poor correlation with MPA AUC0-12. A model utilizing 4 oral concentrations (0, 0.5, 1, and 4 h postdose) over a 12-h period could effectively estimate MPA AUC0-12 with precise results and minimal bias.

Bloodless Medicine in Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (alloHSCT) poses challenges for patients who decline blood products because of religious beliefs or other reasons. Despite potential curative prospects, many institutions refrain from offering alloHSCT to patients who decline blood products because of safety concerns associated with cytopenias. OBJECTIVES: This review focuses on one institution's experience of conducting alloHSCT without blood components, emphasizing preparation and supportive care. METHODS: The approach of conducting alloHSCT without blood components, which involves ABO-compatible donor matching, nonmyeloablative regimens, and pretransplantation optimization of red blood cell production, is discussed. FINDINGS: The clinical team can minimize transfusion needs by using erythropoiesis-stimulating agents, thrombopoietin agonists, and peri- and post-transplantation management strategies. These recommendations can ensure patient safety and successful outcomes with bloodless medicine.

Inflammation-induced epigenetic imprinting regulates intestinal stem cells.

It remains unknown whether and how intestinal stem cells (ISCs) adapt to inflammatory exposure and whether the adaptation leaves scars that will affect their subsequent regeneration. We investigated the consequences of inflammation on Lgr5+ ISCs in well-defined clinically relevant models of acute gastrointestinal graft-versus-host disease (GI GVHD). Utilizing single-cell transcriptomics, as well as organoid, metabolic, epigenomic, and in vivo models, we found that Lgr5+ ISCs undergo metabolic changes that lead to the accumulation of succinate, which reprograms their epigenome. These changes reduced the ability of ISCs to differentiate and regenerate ex vivo in serial organoid cultures and also in vivo following serial transplantation. Furthermore, ISCs demonstrated a reduced capacity for in vivo regeneration despite resolution of the initial inflammatory exposure, demonstrating the persistence of the maladaptive impact induced by the inflammatory encounter. Thus, inflammation imprints the epigenome of ISCs in a manner that persists and affects their sensitivity to adapt to future stress or challenges.

Pre-transplantation levels of lysine (K)-specific methyltransferase 2A (KMT2A) partial tandem duplications can predict relapse of acute myeloid leukemia patients following haploidentical donor hematopoietic stem cell transplantation.

We aimed to identify dynamic changes of lysine (K)-specific methyltransferase 2A partial tandem duplications (KMT2A-PTD) before and after haploidentical donor hematopoietic stem cell transplantation (HID HSCT) and explore the prognostic value of pre-transplantation levels of KMT2A-PTD in acute myeloid leukemia (AML) receiving HID HSCT. Consecutive 64 AML patients with KMT2A-PTD positivity at diagnosis receiving HID HSCT were included in this study. Patients with KMT2A-PTD ≥1% before HSCT had a slower decrease of KMT2A-PTD after HID HSCT. Patients with KMT2A-PTD ≥1% before HID HSCT had a higher cumulative incidence of relapse (36.4%, 95% confidence interval [CI]: 6.3%-66.5%) at 2 years after HSCT than those with KMT2A-PTD <1% (7.5%, 95% CI: 0.3%-14.7%, P = .010). In multivariable analysis, KMT2A-PTD ≥1% before HID HSCT was the only independent risk factor for relapse (hazard ratio [HR]: 4.90; 95% CI: 1.22-19.59; P = .025). Thus, pre-transplantation levels of KMT2A-PTD could predict relapse in AML patients following HID HSCT.

The transplantation effect of pegylated granulocyte colony-stimulating factor mobilized hematopoietic stem cells may be superior to that of G-CSF mobilized hematopoietic stem cells in haploidentical allogeneic hematopoietic cell transplantation.

Granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood stem cells have become the preferred source of hematopoietic stem cells. We compared the effectiveness of G-CSF and pegylated G-CSF (peg-G-CSF) for hematopoietic stem cell mobilization in haploidentical hematopoietic stem cell transplantation (haplo-HSCT) donors, and evaluated the transplant outcomes. We conducted a matched retrospective cohort study. Donors mobilized with peg-G-CSF (n = 70) and G-CSF (n = 70). 140 consecutive patients diagnosed with acute leukemia who underwent haplo-HSCT were included in this study. The findings revealed that the peg-G-CSF cohort exhibited significantly elevated myeloid-derived suppressor cells (MDSCs) levels in their grafts when compared to the G-CSF cohort (P < 0.001). The 100-day cumulative incidence (CI) of grade III-IV acute graft-versus-host disease (GVHD) and 1-year CI of moderate-to-severe chronic GVHD were 4.3% vs 14.3 % (P = 0.047) and 11.2% vs 27.4 % (P = 0.023), in the peg-G-CSF group and G-CSF group. Patients reveiving mobilized stem cell with peg-G-CSF had a significantly greater likelihood of 1-year GVHD-free relapse-free survival (GRFS) compared to patients reveiving mobilized stem cell with G-CSF (74.9% vs 37.9 %, P < 0.001). The higher graft MDSCs proportion was associated with lower grade II-IV aGVHD, cGVHD (P < 0.05) and higher GRFS in the univariate analysis (P < 0.05). Multivariate analysis showed that MDSCs proportion higher than 11.36 % (HR, 0.305; 95 % CI, 0.154-0.606; P = 0.001) and peg-G-CSF for stem cell mobilization (HR, 0.466; 95 % CI, 0.251-0.865; P = 0.016) were independent prognostic factors of GRFS. The superior survival rates observed in recipients of peg-G-CSF-mobilized cells are likely due to reduced acute GVHD, potentially mediated by the increased MDSCs within the grafts.

Early bacteremia following allogeneic hematopoietic stem cell transplantation without antibiotic prophylaxis: epidemiology and antimicrobial resistance.

OBJECTIVE: Bacteremia is a serious complication in patients undergoing allogeneic hematopoietic stem cell transplantation. The aim of this study was to determine the frequency, epidemiological profile, and risk factors of bacteremia early after allogeneic hematopoietic stem cell transplantation. METHODS: An observational descriptive retrospective study was conducted in patients who received transplants between January 2016 and December 2021. Early bacteremia was defined as blood stream infection occurring between Day 0 and Day 100 after transplantation. RESULTS: Forty episodes of early bacteremia occurred in 36/245 transplanted patients. Fifteen episodes (37.5%) were due to gram-positive bacteria and 25 (62.5%) to gram-negative bacteria. The most frequent species isolated were coagulase negative staphylococci (CoNS) in gram-positive bacteremia (n = 8/15), and Klebsiella species (8/25) and Pseudomonas species (8/25) in gram-negative bacteremia. Twenty-nine episodes of bacteremia (72.5%) occurred during the first 30 days after transplantation with a median time of nine days (range: 0-90 days). Coagulase negative staphylococci were methicillin-resistant in 75% of cases, the only Staphylococcus aureus isolated was methicillin-resistant. All gram-positive bacilli were penicillin-resistant. Gram-negative bacilli were multidrug resistant in 61.5% of cases. In multivariate analysis, bone marrow as source of graft (p-value = 0.02) and cytomegalovirus reactivation (p-value = 0.02) were significantly associated with an increased risk of bacteremia. Mortality attributable to bacteremia was 2.8%. The one-year overall survival was not significantly different between those with and without bacteremia. CONCLUSIONS: Bacteremia was more frequent within the first 30 days after transplantation indicating the crucial role of neutropenia. An increase in multidrug resistant gram-negative bacteremia was noted.