Acute and chronic graft-versus-host disease (GVHD) remains major obstacles to the success of allogeneic hematopoietic cell transplantation (allo-HCT). Recent advances in experimental models and clinical studies have refined our understanding of the cellular and molecular mechanisms that drive GVHD and revealed new therapeutic opportunities. Emerging evidence indicates tissue tolerance mediated by epithelial regeneration from tissue stem cells plays a protective role against GVHD. Furthermore, we recently found tissue stem cells persisting after acute GVHD have epigenetic changes that lead to GVHD exacerbation at GVHD flare. Chronic GVHD develops through a more complex immunopathology involving T and B cells, macrophages, and fibroblasts. Disrupted immune reconstitution, including impaired thymic tolerance, aberrant B-cell activation driven by BAFF, and defective regulatory T-cell recovery, contributes to sustained alloimmunity. T-cell exhaustion has recently been recognized as a central checkpoint: While terminal exhaustion promotes tolerance, early calcineurin inhibitor (CNI) administration suppresses terminal exhaustion and drives the accumulation of transitory exhausted T cells that mediate chronic GVHD while preserving graft-versus-leukemia (GVL) activity. Post-transplant cyclophosphamide (PTCy)-based platforms highlight how delayed CNI initiation reduces chronic GVHD by permitting donor T cells to undergo exhaustion.

Class I myosins form an abundant group of single-headed motor proteins that interact with actin and membrane phospholipids and are employed in a variety of cell processes like cell shape remodeling, motility and invasion, exocytosis, and endocytosis. The large number of class members and their uneven distribution in human cells and tissues complicate their study. Furthermore, this hinders the assessment of their biomarker potential and mechanistic role in oncogenesis and other diseases. Despite the emerging data on their mutations and altered abundance in a number of tumors and other diseases, most studies examine class I myosins individually or in groups of several proteins. Thus, the question of their redundancy and possible functional substitution is ignored. In this work, we simultaneously assess all eight human MYO1 genes on cell lines of different origins by RNA-seq re-analysis. We also report a qPCR system for human myosin I screening and test it on a set of 35 continuous cell lines widely used in biomedicine and fundamental research. These data clarify the restricted expression patterns of MYO1 genes in various human cell types and allow to assess the pattern specific of haematopoietic cell lines.

Allogeneic haematopoietic cell transplantation (alloHCT) remains a potentially curative strategy for relapsed or refractory lymphoid malignancies, even in the post-chimeric antigen receptor T-cell and bispecific antibody era. While reduced-intensity conditioning regimens offer lower non-relapse mortality (NRM), relapse rates remain high, and optimal conditioning strategies in the setting of post-transplant cyclophosphamide (PTCy) prophylaxis remain undefined. In this retrospective, international multicentre study, the primary end-point was NRM. We compared treosulfan/fludarabine (Treo/Flu) versus thiotepa/busulfan/fludarabine (TBF) in 178 adults with lymphoid malignancies undergoing first alloHCT with PTCy and peripheral blood grafts. Three-year NRM was 14.0% with Treo/Flu versus 33.0% with TBF. On multivariate analysis, Treo/Flu was associated with significantly lower 3-year NRM (hazard ratio [HR] 0.44; 95% confidence interval [CI], 0.22-0.87; p = 0.018). Conditioning regimen was not independently associated with overall survival (OS) or progression-free survival (PFS), and relapse incidence was similar between regimens. Moderate to severe chronic graft-versus-host disease (GVHD) was higher with Treo/Flu (26.0% vs. 9.9%; HR 2.43; 95% CI, 1.09-5.43; p = 0.03), while GVHD-free/relapse-free survival (GFRS) was comparable. Findings were consistent in a prespecified propensity score-matched sensitivity analysis. These findings support Treo/Flu as a potentially safer reduced-toxicity conditioning option than TBF in the context of PTCy-based GVHD prophylaxis for lymphoid malignancies and warrant prospective validation.

Introduction Endothelial injury is a major contributor to morbidity and mortality in pediatric patients undergoing hematopoietic cell transplantation (HCT). It appears as sinusoidal obstruction syndrome (SOS) or transplant-associated thrombotic microangiopathy (TMA), among other conditions. Composite indices like the Endothelial Activation and Stress Index (EASIX) and its modified version (m-EASIX) may serve as accessible biomarkers for early identification. However, their utility in pediatric populations is unestablished. We aimed to explore whether EASIX and m-EASIX can help identify endothelial complications in this setting. Methods We conducted a prospective, single-center observational cohort study of 31 children and young adults undergoing HCT. Serial measurements of EASIX and m-EASIX scores, based on standard laboratory parameters, were collected at baseline and at multiple post-HCT time points (Days 0, 7, 14, 21, 28, and 100). Results Within 100 days after HCT, SOS and/or TMA developed in six patients. At Day 21, EASIX and m-EASIX scores were significantly higher in children with endothelial complications than in controls. The m-EASIX score also showed predictive value at Day 14. Receiver operating characteristic analysis showed discrimination at Day 21 for both scores (AUCs of 0.807 for EASIX and 0.865 for m-EASIX). Changes from baseline to Day 21 further improved accuracy, with thresholds achieving high sensitivity for screening patients at increased risk of SOS and/or TMA. The Day 21 landmark is most relevant for identifying patients at risk of later-onset or persistent endothelial injury, which remains clinically significant. Conclusions Our findings suggest that EASIX and m-EASIX may serve as practical and dynamic biomarkers for detecting endothelial injury in pediatric HCT recipients. The observation that Day 21 scores and their changes from baseline correlate with later complications highlights a potential window for risk stratification. However, these results should be interpreted cautiously, given the single-center design and limited sample size. Further research is needed to confirm whether these indices can reliably guide clinical decisions across diverse settings. Exploring their use in populations where reduced-intensity conditioning (RIC) and alternative donors are standard could provide important insights. Multicenter studies will be essential to validate these preliminary observations and refine biomarker-based strategies for post-HCT care.

Metabolic control of innate immune activation in TET2-mutant clonal hematopoiesis.

Hematopoietic cell transplant (HCT) for sickle cell disease from human leukocyte antigen (HLA)-identical sibling and alternate donors is associated with excellent outcomes. HCT was implemented under restrictive eligibility and exclusion criteria because mortality was >10% in the early experience. These restrictive criteria were carried over to contemporary HCT and gene therapy (GT) clinical trials. Additionally, patients with chronic pain, stroke, psychiatric disorders, or adherence issues were excluded from GT trials. The United States Food and Drug Administration qualification of GT broadly identifies recurrent vaso-occlusive episodes (VOE) as the indication and stipulates no exclusion criteria, thus raising the question of which criteria to use in clinical GT. Excellent overall and event-free survival, improvement in health-related quality of life, amelioration of VOE, and stabilization of cerebral vasculopathy following HLA-identical sibling donor HCT and GT justify broad application of GT in patients with a history of severe VOE, with shared decision-making guided by patient preferences while acknowledging gaps in evidence.

Accumulated studies have reported that hematopoietic differentiation was primarily regulated by transcription factors. Early B cell factor 1 (EBF1) is an essential transcription factor for B lymphopoiesis. Contrary to the canonical notion, we found that a single miRNA, miRNA-195 (Mir195) transduction let Ebf1-deficient hematopoietic progenitor cells (HPCs) express CD19, carry out V(D)J recombination and class switch recombination, which implied that B cell matured without EBF1. A part of the mechanism was caused by FOXO1 accumulation via inhibition of FOXO1 phosphorylation pathways in which targets of Mir195 are enriched. These results suggested that some miRNA transductions could function as alternatives to transcription factors.

Background The Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) assigns a high-risk score to patients who develop secondary hematologic malignancies following solid tumors, indicating an increased risk of non-relapse mortality (NRM). This study aimed to evaluate the impact of prior solid tumors on outcomes after hematopoietic stem cell transplantation (HSCT). Methods From a cohort of 2,382 patients who underwent HSCT for acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), or myelodysplastic syndrome (MDS) between January 2014 and July 2024, we included 43 (1.8%) with a history of prior solid tumors and 82 matched controls for analysis by 1:2 propensity score matching. Results The solid tumor cohort predominantly comprised breast cancer (48.8%). With a median follow-up of 31.0 months, only one patient exhibited post-transplant relapse or metastasis of the solid tumor. Compared to the control group, patients with solid tumors exhibited higher ECOG scores (≥ 2: 23.1% vs. 9.5%, P = 0.049), lower platelet counts (35.5 vs. 72×10 9 /L, P = 0.010), a higher incidence of complex karyotypes (16.3% vs. 3.7%, P = 0.031). No significant differences were noted in 3-year overall survival (OS) (64.3% vs. 71.9%, P = 0.468), leukemia-free survival (LFS) (57.6% vs. 70.8%, P = 0.218), graft-versus-host disease/relapse-free survival (GRFS) (43.3% vs. 53.0%, P = 0.359) and NRM (23.9% vs. 11.7%, P = 0.246). In an exploratory landmark analysis, the solid tumor cohort appeared to have significantly lower OS (P = 0.030), LFS (P = 0.009), and GRFS (P = 0.038) from 2 years after transplantation. Multivariable analysis identified age greater than 55 years, baseline platelet counts less than 50×10 9 /L as significant predictors of inferior OS and LFS in solid tumor patients. Conclusion Patients with hematologic diseases secondary to solid tumors showed no significant increase in overall transplantation risk. However, their adverse clinical characteristics and reduced long-term survival rates beyond 2 years post-transplantation, underscore the need to refine HCT-CI scoring and improve management strategies.

BK virus infection is a marker of poor immune recovery, especially after kidney or allogeneic cell transplantation. Because of the challenges associated with BK virus infection and the lack of effective treatments, there is a growing interest in novel approaches, such as adoptive cellular therapy, that aim to restore antiviral immunity and promote viral clearance. Our clinical trial assessed the feasibility, safety, and efficacy of administering third-party, BK virus-specific cytotoxic T lymphocytes (CTLs) used to treat allogeneic HCT patients and kidney transplant patients with biopsy-proven BK-virus nephropathy. Comprehensive clinical assessments and correlative studies were performed. The study included six patients after kidney-transplantation and five HCT recipients. Viremia declined in most evaluable patients by Day 45 after BKCTL infusion. No new instances of graft-versus-host disease, kidney-transplant rejection, graft failure, or infusion-related toxicities were attributed to the treatment. Antiviral activity (as assessed by interferon-γ secretion) did not differ between infused BKV-CTLs given to kidney-transplant versus allogeneic SCT recipients. In this study, we longitudinally tracked the in vivo persistence of adoptively transferred BKV-CTLs and demonstrated their sustained functional activity. This therapy could be promising in KT and SCT patients with recent-onset BK-virus viremia.

Organometallic and metal-organic compounds are widely used in different fields of chemistry and allied disciplines, including bioinorganic and medicinal chemistry. Of particular interest is the development of novel potential anticancer agents based on palladium(II) complexes of the so-called pincer-type ligands, featuring a specific monoanionic tridentate framework. In this work, hybrid imine-thiocarbamate ligands are shown to readily undergo direct cyclopalladation in solution and under solvent-free conditions, in particular upon mechanochemical activation, yielding a series of Pd(II) pincer complexes. The latter exhibit promising cytotoxic activity against several solid and hematopoietic cancer cell lines.

Kidney dysfunction is a significant complication of allogeneic hematopoietic cell transplantation (alloHCT). Standard serum creatinine (sCr) testing is imperfect due to latency from the event causing damage to sCr increase. The purpose of this study was to evaluate the role of kidney damage biomarkers in the field of alloHCT. Seventy adult alloHCT candidates from 2 centers were recruited. 34 patients constituted pilot cohort and 36 – validation cohort. In pilot cohort serum and urine samples obtained at baseline and 7 timepoints were tested using ELISA assays for LFABP-1, KIM-1, NAG, uromodulin, TIMP-2 and IGFBP-7. Urine concentrations were corrected to urine creatinine concentration (uCr). Results were analyzed as predictors of acute kidney injury (AKI) within 100 days from alloHCT using receiver operating curve (ROC). LFABP-1, KIM-1, uromodulin, NAG and TIMP-2 performed significant predictive value for AKI. The best results were obtained for LFABP-1 and NAG and these biomarkers were tested in validation cohort where the results were borderline significant. Given the heterogeneity of the studied population, calculations for the whole group were performed: ROC for day +7/baseline ratio of urinary LFABP-1 and NAG in predicting AKI within 100 days from alloHCT was 0.673 and 0.678 respectively (p < 0.05). ROC for baseline urinary LFABP-1 in predicting early AKI was 0.721 (p < 0.05). Findings from our study confirm that patients undergoing alloHCT frequently experience subclinical kidney damage. However, due to the multifactorial nature of renal insults and preexisting kidney impairment, the predictive value of studied biomarkers in this population is limited.

Favorable outcomes with fludarabine, melphalan, and total-body irradiation 8-12Gy as an intensified conditioning regimen for adult allogeneic HCT.

A phase 1/2 study of donor-derived anti-CD33 CAR T-cell therapy (VCAR33) for relapsed/refractory AML after allogeneic HCT.

The gut microbiota has emerged as a critical factor influencing outcomes following allogeneic hematopoietic cell transplantation (alloHCT). Notably, disruptions to the intestinal microbiome-referred to as dysbiosis-have been strongly linked to the development of acute graft-versus-host disease (aGVHD). The gut microbiome interacts closely with the host immune system, influencing both immune reconstitution and alloHCT complications. As a result, microbiome-targeted strategies are being investigated to improve outcomes and include antibiotic stewardship, prebiotic and diet intervention, probiotics including fecal microbiota transfer (FMT) and postbiotics. These approaches are being investigated not only as a therapeutic intervention in particular for aGVHD, but also as preventive strategies.

Varnimcabtagene autoleucel for adults with relapsed or refractory B-cell precursor acute lymphoblastic leukaemia in Spain (CART19-BE-02): a multicentre, single-arm, phase 2 trial.

Introduction Immune reconstitution is a critical parameter in successful hematopoietic cell transplantation (HCT) and involves different cell types and a microenvironment including cytokines. Natural killer (NK) cells and γδ T cells are known to repopulate early after HCT and are proposed to have the intriguing capacity of mediating graft-versus-leukemia (GVL) effects without accompanying graft-versus-host-disease (GVHD). Interleukin-15 (IL-15) and interleukin-7 (IL-7) are key homeostatic cytokines, with effects on both T and NK cells, making these cytokines especially interesting in an HCT setting. Methods In this prospective study, we investigated associations between IL-15 and IL-7, NK cells and γδ T cells, including activated subtypes, and clinical outcomes. We included 105 patients undergoing allogeneic HCT at a single-center institution. IL-15, IL-7, and extended T and NK cell phenotyping were measured longitudinally at fixed time points following HCT. Results We found high IL-15 concentrations early post-transplant to be significantly associated with reduced overall survival, reduced relapse-free survival, and excess acute GVHD. Furthermore, IL-15 showed significant inverse correlations with NK cells and γδ T cells, including activated subtypes early after HCT, and with conventional T cells at later time points. IL-7 was significantly inversely correlated not only with conventional T cells but also with γδ T cells early after HCT. Discussion These findings may suggest that early immune reconstitution of NK cells and γδ T cells is influenced by the bioavailability of IL-15 after HCT and that IL-15 could have a mechanistic effect in the activity of these innate effector cells. NK cells and γδ T cells are currently being investigated in several promising treatment settings, and IL-15 here may offer a potential benefit.

Expression levels of human leukocyte antigen (HLA) are associated with susceptibility to various diseases and outcomes after allogeneic hematopoietic cell transplantation (allo-HCT). However, there has been no comprehensive analysis of the effect of the expression levels of the HLA-A, -B, -C, and -DRB1 alleles in unrelated (UR)-HCT. Using the Capture RNA-Seq method, we analyzed the gene expression of HLA alleles in 443 healthy donors and determined the allele-specific transcription levels (AST levels). We assigned median (M)-AST levels to HLA typing data of patients who received a transplant from HLA-A, -B, -C, and -DRB1-matched unrelated donors using transplant registry data. All 6,084 patients were divided into low, middle, and high tertile groups according to the distribution of the sum of the two alleles of the M-AST level for each HLA locus and the sum of the eight alleles of the M-AST level for all four loci. The risk of grade II-IV acute graft-versus-host disease (GVHD) was significantly higher in the middle group (hazard ratio, 1.11; P = 0.044) and high group (hazard ratio, 1.20; P < 0.001) than in the low group for the sum of the HLA-A, -B, -C, and -DRB1 loci. Similar results were observed at the HLA-A, -B, -C, and -DRB1 loci. Higher transcription levels were also associated with a lower risk of relapse at the HLA-B, -C, and -DRB1 loci. Our data suggest that a high transcription level of patient and/or donor HLA may evoke strong alloimmune responses and affect UR-HCT outcomes.

Possible increased risk of Epstein-Barr virus (EBV) infection and post-transplant lymphoproliferative disease (PTLD) in letermovir-exposed haematopoietic cell transplantation recipients: right-to-reply.

Aging is a dominant risk factor for chronic diseases characterized by the functional decline of tissues and organs. During aging, the hematopoietic system declines in regenerative capacity-seemingly attributable to increases in DNA damage, replicative stress, and autophagic flux-resulting in skewing towards a myeloid lineage and away from a lymphoid lineage. Here, we characterized the transcriptomic and cellular landscape of the aged C57Bl/6J mouse hematopoietic system using a combination of bulk RNAseq and single cell RNAseq (scRNAseq). We show that aging leads to global transcriptional alterations in bulk peripheral blood mononuclear cells (PBMCs), lineage marker-depleted bone marrow cells (Lin-BM), and in hematopoietic stem and progenitor cells (HSPCs), immunophenotypically lineage marker negative (Lin-) Sca1+ cKit+ (LSK+). These changes indicate widespread activation of inflammatory processes, namely in PBMCs and Lin-BM cells. Interestingly, there is also a downregulation of cell cycle genes in HSPCs during aging. ScRNAseq across 39 hematopoietic cell types revealed age-related skewing in cell composition. Aged PBMCs showed significant decreases in CD4 and CD8 naïve cells concomitant with increases in CD4/8 memory and CD8 exhausted T cell populations. Lin-BM cells showed significant myeloid skewing in common myeloid progenitor (CMP) cells, as well as in the HSC population. We also identified a unique HSC population marked by increased Vwf, Wwtr1, and Clca3a1 expression that does not exist in young HSCs, thus likely marking true aged HSCs. Collectively, this work should serve as a useful resource for understanding and therapeutically targeting the aged hematopoietic system.

Hematopoietic progenitor cell collection (HPC-C) by apheresis after granulocyte-colony stimulating factor (G-CSF) stimulation is a routine worldwide procedure. The first apheresis procedure is typically performed on Day 5 of G-CSF administration. We aimed to evaluate whether initiating the apheresis procedure on Day 4, with 1 day shorter G-CSF exposure for the donor, affects collection outcomes. This study included healthy, unrelated donors who underwent HPC-C by apheresis after G-CSF administration between April 2022 and February 2024 at our center. Of 182 unrelated donors, 34.6% underwent apheresis on Day 4 of G-CSF treatment and 65.4% on Day 5. There was no significant difference between the two groups in terms of collected CD34+ cell yield (p = 0.369) or the need for a second apheresis procedure (p = 0.74). Successful mobilization was achieved in 93.7% of donors who underwent a single apheresis procedure on Day 4 and in 95% of those who underwent a single apheresis procedure on Day 5 (p = 0.477). In donors requiring two consecutive apheresis procedures, the collected CD34+ cell yield was higher in those who initiated apheresis on Day 4, although this difference was not statistically significant (p = 0.067). This is the first study comparing HPC-C outcomes on Days 4 and 5 of G-CSF administration exclusively in unrelated donors. Our data indicate no difference in the collected CD34+ cell yield or the need for a second apheresis procedure between the two groups. Initiating apheresis on Day 4 may allow for 1 day less G-CSF exposure without compromising collection outcomes.