SEARCH · Search PubMed

Results for “CD34+”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed2025

Efficacy of Repeated Administration of Cultured Human CD34+ Cells Against Streptozotocin-Induced Diabetic Nephropathy in Rats.

To date, no clinical trial has investigated the potential of CD34+ cells to treat diabetic nephropathy. This study examined the efficacy of human CD34+ cells against diabetic nephropathy in rats. Rats were administered streptozotocin (STZ) intraperitoneally and divided into three groups: normal control, STZ control, and STZ plus cell therapy. The STZ-plus-cell-therapy group was administered human umbilical cord blood-derived CD34+ cells weekly for three weeks. At eight weeks, the rats' renal function, pathology, and transcriptome profiles were assessed. Although blood glucose levels did not differ between the STZ-administered groups, urinary albumin excretion was significantly lower at 6 weeks in the STZ-plus-cell-therapy group than in the STZ control group (p < 0.001). Serum creatinine levels tended to be higher in the STZ control group and lower in the STZ-plus-cell-therapy group. Cell therapy significantly improved mesangial expansion, interstitial fibrosis, peritubular capillary rarefaction, and glomerular macrophage infiltration compared with the STZ control (p < 0.0001). Kidney transcriptomics revealed significant upregulation of genes related to M2 macrophage markers, cell homing, and angiogenesis in the STZ-plus-cell-therapy group. In rats with STZ-induced diabetic nephropathy, human CD34+ cells ameliorated renal injury through their anti-inflammatory and pro-angiogenic effects.

Animals↗

PubMed2026

Standardizing stem cell enumeration: A methodological comparison of single and dual flow cytometry platforms.

Two flow cytometry methods are used for stem cell (CD34+) enumeration; single platform (SP) and dual platform (DP). While several studies reported comparable results, others suggested superiority of the SP method. This study evaluated variations between both methods using a modified workflow. A total of 54 fresh and thawed specimens, including mobilized peripheral blood, apheresis products, and umbilical cord blood, were analyzed using both methods. High concordance between SP and DP methods was observed for absolute viable CD34+ counts in fresh and thawed specimens (p = 0.088 and 0.427, respectively), as well as for CD34+ viability (p = 0.085 and 0.801). Absolute viable WBC counts were comparable between methods in thawed specimens (p = 0.124), whereas a modest statistical variation was observed in fresh specimen group (p = 0.039), largely influenced by umbilical cord blood samples. Variation in absolute viable CD34+ counts remained within clinically acceptable limits, with median variations of 2.4 for fresh and 1.4 for thawed samples. SP and DP methods demonstrated high concordance for absolute viable CD34+ enumeration and CD34+ viability in fresh and thawed specimens. Although a modest variation in viable WBC counts was observed in fresh samples, this did not affect CD34+ enumeration and remained clinically acceptable. While SP provides a standardized approach, the DP method offered greater gating flexibility, with fewer technical resources required, and was approximately 70% more cost-effective, supporting its use as a practical alternative in appropriate laboratory settings.

Humans↗

PubMed2025

Quantifying the mutational landscape of retroviral and lentiviral vectors in gene therapy patients.

Adenosine deaminase severe combined immunodeficiency (ADA-SCID) is a monogenic disorder caused by mutations in the ADA gene. Gene therapy using γ-retroviral and lentiviral vector gene addition approaches have shown curative results. We sequenced the ADA transgene in transduced CD3+ T cells, and in peripheral blood cells from patients treated with autologous CD34+ cells transduced with either a γ-retroviral or lentiviral ADA gene vector to assess transgene mutational profiles. In both CD3+ T cells and ADA-SCID patients' cells treated with the lentiviral vector, we observed significantly higher occurrences of guanine (G)-to-adenosine (A) base substitutions than with the γ-retroviral vector. We hypothesized that this G-to-A mutational signature was due to the APOBEC3 cytosine deaminase protein family. By knocking out APOBEC3 genes in HEK239T packaging cells, APOBEC3-mediated mutagenesis decreased by 91.2% along the transgene in CD34+ transduced cells in comparison to CD34+ cells transduced with lentiviral supernatant packaged in parental HEK293T cells.

Humans↗

PubMed2026

AML1-ETO hijacks a distal enhancer of NAT10 to reprogram glutathione metabolism and sustain leukemia stem cell stemness.

Chromosomal translocations produce oncogenic fusion proteins such as AML1-ETO, which predominantly occupy gene promoters to induce transcriptional reprogramming in leukemia stem cells (LSCs), consequently driving the pathogenesis of t(8;21) acute myeloid leukemia (AML). However, whether AML1-ETO is recruited to additional regulatory DNA elements to orchestrate oncogenic gene expression programs has not been fully addressed. Here, we define AML1-ETO and H3K27ac CUT&Tag landscapes in primary t(8;21) AML CD34+ cells and t(8;21) AML cell lines, revealing AML1-ETO binding at a distal enhancer of the RNA N4-acetylcytidine (ac4C) writer N-acetyltransferase 10 (NAT10), thereby driving its transcriptional activation. Genetic ablation or pharmacological inhibition of NAT10 restricted the survival and self-renewal of LSCs in primary t(8;21) AML CD34+ cells, as well as in a retroviral AML1-ETO9a-driven t(8;21) AML mouse model, establishing NAT10 as a potential therapeutic vulnerability. Mechanistically, NAT10 is recruited to glutathione S-transferase omega 2 (GSTO2) mRNA to catalyze ac4C modification, thereby enhancing transcript stability and reprogramming glutathione metabolism, as demonstrated by ac4C profiling, RNA immunoprecipitation (RIP), and dCas13b-NAT10-based analyses. Silencing of GSTO2 in primary t(8;21) AML CD34+ cells decreased intracellular reduced glutathione (GSH) levels and compromised LSC survival and self-renewal, whereas GSTO2 overexpression or GSH supplementation largely rescued LSC maintenance following NAT10 loss. Collectively, these findings enrich and extend the understanding of AML1-ETO regulatory programs by linking distal enhancer activity to a NAT10-GSTO2 ac4C-GSH axis that integrates epigenomic, posttranscriptional, and metabolic reprogramming to sustain LSC stemness, highlighting this circuit as a potential therapeutic vulnerability in t(8;21) AML.

Humans↗

PubMed2026

Ex vivo long-term expansion of human hematopoietic stem and progenitor cells as a tool for modeling vector integration sites and clonality.

BACKGROUND: Gene therapy (GT) using retroviral vectors (RVs) is efficacious in treating monogenic diseases. However, there is an inherent risk for severe adverse effects due to insertional mutagenesis. Preclinical safety assessment and patient monitoring are inevitable in GT. To assess the genotoxic risk of novel RV vectors, mainly murine hematopoietic stem and progenitor cells (HPSCs) are routinely used, because human HSPCs cannot be immortalized in vitro using mutagenic vectors. In this study, we aim to identify early signs of clonal outgrowth by performing integration site analyses (ISA). METHODS: The small molecules A83-01, pomalidomide, and UM171 (APU) were used for the ex vivo expansion, lentiviral transduction, and long-term cultivation of umbilical cord blood-derived HSPCs. We determined the influence of APU on the stemness of HSPCs and their differentiation capacity via single-cell RNA sequencing (scRNA seq) and in xenotransplantation studies. To track vector insertion site dynamics, we transduced 7-day expanded HSPCs with a mutagenic or a safer RV. ISA was conducted in human HSPCs over a 5-week cultivation in vitro and compared to the bone marrow of xenotransplanted mice to assess clonal skewings. RESULTS: APU supported the expansion of CD34+CD38-CD45RA-CD90+EPCR+ HSPCs. scRNA seq confirmed the enrichment of HSC signature genes in APU-expanded HSPCs compared to the clinically used medium SFT3 (SCF, FLT3-L, TPO, IL-3). After RV transduction, APU still maintained around 30% of CD34+ cells for 5 more weeks. Without the compounds, already 2 weeks post-transduction, less than 10% of cells were CD34+. The long-term culture allowed the detection of high-risk integrations of the mutagenic SIN-LV.SF in MEIS1 or SUSD6 due to their increasing abundance over time. Bone marrow of xenotransplanted mice was less clonal but did not support the outgrowth of insertional mutants. Overall, APU increased clonal diversity. CONCLUSIONS: Our findings propose that long-term cultivation of transduced HSPC in APU allows for outgrowth of clonal integration sites. The decrease of clonality has been observed in gene therapy patient's years after treatment. Thus, the in vitro model could be used to develop novel human HSPC-based genotoxicity assays that predict insertional mutagenesis, in addition to existing preclinical biosafety assays.

Humans↗

PubMed2026

Effect of adding umbilical cord blood derived stem cells to haploidentical stem cell transplant (haplo-cord) on post-transplant survival and graft-versus-host disease in patients with hematological malignancies: A systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES: Haploidentical stem cell transplantation (haplo-SCT) carries a substantial risk of graft-versus-host disease (GvHD), whereas umbilical cord blood (UCB) transplantation offers lower GvHD risk but slower engraftment. The haplo-cord approach combines both graft sources, aiming to mitigate GvHD while ensuring timely engraftment. This meta-analysis compares haplo-cord transplantation with haplo-SCT alone for the treatment of hematological malignancies. METHODS: Four electronic databases and two clinical trial registries were systematically searched. Effect sizes from eligible studies were pooled using odds ratios (ORs) for dichotomous outcomes and hazard ratios (HRs) for time-to-event outcomes. RESULTS: Twelve studies met the inclusion criteria. Haplo-cord was associated with a statistically significant reduction in chronic GvHD (OR = 0.62, 95%-CI: 0.42-0.93), while no significant difference was observed for grade II-IV acute GvHD (OR = 0.75, 95%-CI: 0.52-1.09). Survival outcomes favored haplo-cord, with lower HRs for overall survival (HR = 0.68, 95%-CI: 0.53-0.86) and event-free survival (HR = 0.61, 95%-CI: 0.52-0.72), while non-relapse mortality was not significant. Relapse at 3 years was significantly lower with haplo-cord (OR = 0.54, 95%-CI: 0.35-0.82). Haplo-cord also demonstrated higher day-30 engraftment, along with lower relapse-related and GvHD-related mortality, while CMV and EBV viremia showed no difference between groups. CD34 selection in the haplo graft significantly influenced effect sizes and heterogeneity in both subgroup analyses and meta-regression for acute GvHD. CONCLUSION: Haplo-cord transplantation improves GvHD outcomes, survival, and relapse risk compared with haplo-SCT alone. However, whether protocol optimization, possibly via CD34 selection, confers additional benefit remains uncertain and requires confirmation in future studies.

Humans↗

PubMed2024

Engineering an inducible leukemia-associated fusion protein enables large-scale ex vivo production of functional human phagocytes.

Ex vivo expansion of human CD34+ hematopoietic stem and progenitor cells remains a challenge due to rapid differentiation after detachment from the bone marrow niche. In this study, we assessed the capacity of an inducible fusion protein to enable sustained ex vivo proliferation of hematopoietic precursors and their capacity to differentiate into functional phagocytes. We fused the coding sequences of an FK506-Binding Protein 12 (FKBP12)-derived destabilization domain (DD) to the myeloid/lymphoid lineage leukemia/eleven nineteen leukemia (MLL-ENL) fusion gene to generate the fusion protein DD-MLL-ENL and retrovirally expressed the protein switch in human CD34+ progenitors. Using Shield1, a chemical inhibitor of DD fusion protein degradation, we established large-scale and long-term expansion of late monocytic precursors. Upon Shield1 removal, the cells lost self-renewal capacity and spontaneously differentiated, even after 2.5 y of continuous ex vivo expansion. In the absence of Shield1, stimulation with IFN-γ, LPS, and GM-CSF triggered terminal differentiation. Gene expression analysis of the obtained phagocytes revealed marked similarity with naïve monocytes. In functional assays, the novel phagocytes migrated toward CCL2, attached to VCAM-1 under shear stress, produced reactive oxygen species, and engulfed bacterial particles, cellular particles, and apoptotic cells. Finally, we demonstrated Fcγ receptor recognition and phagocytosis of opsonized lymphoma cells in an antibody-dependent manner. Overall, we have established an engineered protein that, as a single factor, is useful for large-scale ex vivo production of human phagocytes. Such adjustable proteins have the potential to be applied as molecular tools to produce functional immune cells for experimental cell-based approaches.

Humans↗

PubMed2025

CAR NK cell production from human cord blood NK progenitor cells is enhanced by stimulation of the IL-15 receptor.

Cord blood (CB)-derived chimeric antigen receptor (CAR) natural killer (NK) cells have demonstrated significant antitumor efficacy. We recently reported that CB-derived CAR NK cells predominantly originate from CD7+CD56-CD34-HLA-DR-Lin- NK cell precursors in CB. Here, we demonstrate that stimulating the interleukin (IL)-15 receptor on these NK precursors enhances the production of CAR NK cells from CB cells. In CB CD56-CD34-HLA-DR-Lin- cells, the IL-15 receptor was exclusively expressed on CD7+ NK cell precursors. Using K562 feeder cells that express not only 4-1BB ligand and membrane-bound (mb) IL-21 but also mbIL-15 significantly increased the production of mature NK cells from the purified NK cell precursors or T cell-depleted CB cells. The in vitro and in vivo antitumor effects of CAR NK cells generated using K562 feeder cells that express mbIL-15 were comparable to those of CAR NK cells produced using K562 feeder cells that do not express mbIL-15. These results suggest that K562 feeder cells expressing 4-1BBL, mbIL-21, and mbIL-15 can increase the production of CAR NK cells from CB cells while maintaining their cytotoxic potential. This method could also be useful for expanding NK cells from CB for any type of adoptive NK cell therapy with or without CAR transduction.

Humans↗

PubMed2025

Prime Editing for p47phox-Deficient Chronic Granulomatous Disease.

Chronic granulomatous disease (CGD) is a severe monogenic immunodeficiency caused by damaging variants in genes required for microbicidal NADPH oxidase activity. Autosomal recessive p47phox-deficient CGD (p47-CGD) is predominantly caused by a two-nucleotide deletion in exon 2 (delGT) of NCF1. We developed PM359, an autologous CD34+ hematopoietic stem-cell therapy in which prime editing is used to correct delGT. Two participants received PM359 after myeloid conditioning with busulfan: neutrophils and platelets engrafted promptly in both patients. Adverse events were consistent with myeloid conditioning with busulfan. NADPH oxidase activity was observed in neutrophils within 1 month and was maintained for 6 months and 4 months as of the last follow-up visit in Participants 1 and 2, respectively. These results support further investigation of prime editing of CD34+ cells to treat p47-CGD. (Funded by Prime Medicine; ClinicalTrials.gov number, NCT06559176.).

Adolescent↗

PubMed2026

Emerging Molecularly Defined Bone and Soft Tissue Diagnoses: When Do They Matter?

With the rapid advancement of molecular pathology and the explosion of genomic data, our understanding of neoplasms continues to evolve. In this review, we introduce 3 recently classified mesenchymal neoplasms, the categorization of which was refined based on their underlying molecular genetic profiles. These entities were recently highlighted by the senior author at the United States and Canadian Academy of Pathology Long Course. To underscore the importance of their proper recognition, this review was prepared to reach a broader audience. Recognition of these tumors is particularly important because their mimickers often have markedly disparate prognoses and management strategies, making accurate diagnosis critical. The 3 entities discussed in this study are the following: (1) SRF-rearranged myoid neoplasms (formerly cellular myofibroma), (2) superficial CD34-positive fibroblastic tumors, and (3) kinase-altered spindle cell neoplasms. This review aimed to highlight the key clinicopathologic features of these tumors to facilitate accurate diagnosis, discuss ancillary studies that assist in navigating the differential diagnoses, and outline strategies to avoid common diagnostic pitfalls. Finally, we emphasize when molecular characterization may be necessary to guide diagnosis and support appropriate clinical management.

Humans↗

PubMed2025

The first case of GOLGA5-RET fusion-positive malignant spindle cell sarcoma of the head and neck responsive to selpercatinib.

Soft-tissue sarcoma (STS) is a rare malignancy that accounts for less than 1% of all cancers, and recent advances in molecular biology have led to its classification based on genomic information. Some RET-rearranged neoplasms have been reported to present pathological features similar to Neurotrophic Tyrosine Kinase Receptor-rearranged spindle cell neoplasms. Here, we report the first case of head and neck spindle cell sarcoma with a GOLGA5-RET fusion that demonstrated a sustained clinical response to selpercatinib, identified through targeted next-generation sequencing (NGS). The patient was a 43 year-old man with a tumor in the arytenoid region that was resected and diagnosed as a malignant spindle cell tumor. Despite initial treatment with surgical resection alone, local recurrence was confirmed, requiring salvage therapy with total laryngectomy and bilateral cervical dissection. Surgical specimen revealed a spindle tumor with a patternless pattern and collagenous stroma. Immunohistochemistry (IHC) with positivity for CD34, bcl-2 (focally), S100, and weak nuclear staining for STAT6, with absence of expression of CK AE1/3, desmin, c-kit, smooth muscle actin, myogenin, synaptophysin, and SOX10. Trk A/B/C were also negative on IHC. Following confirmation of multiple lung metastases, the patient was treated with doxorubicin monotherapy. Targeted NGS identified GOLGA5-RET rearrangement, FGF14 amplification (equivocal), CDKN2B loss, and CDKN2A loss. GOLGA5-RET rearrangements were validated through fluorescence in situ hybridization. The patient subsequently was enrolled in a phase 1/2 trial for the selective RET inhibitor selpercatinib, resulting in a sustained partial response over 5 years. Although solitary fibrous tumor (SFT) was initially considered as a differential diagnosis based on immunohistochemical findings, the lack of strong and diffuse STAT6 expression made this diagnosis unlikely. Subsequent next-generation sequencing (NGS) revealed a RET fusion, leading to the diagnosis of an RET-rearranged spindle cell neoplasm. This case highlights the importance of genomic testing for certain spindle cell sarcomas and the potential benefit of RET-specific inhibitors against RET-altered sarcomas.

Next-generation sequencing↗

PubMed2026

PIP3 antagonist as a molecular regulator in MSC-derived cardiomyocytes: Potential in vitro therapeutic implications for conotruncal heart defects.

Conotruncal heart defects (CTDs) account for approximately one-third of all congenital heart defects. Elevated levels of phosphatidylinositol (3,4,5)-trisphosphate (PIP3) may contribute to CTD pathogenesis. PIP3 plays a pivotal role in mechanotransduction-based biological processes and remodeling of cardiac cytoskeletal proteins. Here, we aimed to evaluate the efficacy of the 322PESB derivative compound as a molecular regulator that antagonizes PIP3 binding pleckstrin homology (PH) domain of the Akt protein using mesenchymal stem cell-derived cardiomyocyte. Human adipose-derived MSCs (Ad-MSCs) were isolated. Immunophenotypic features of the hAd-MSCs were characterized according to minimal criteria of the international society for cellular therapy (ISCT) including immunophenotyping and trilineage differentiation potential. Subsequently, the differentiated hAd-MSCs were cultured in cardiomyogenesis-inducing medium. Successfully differentiated cardiomyocytes were assessed by measuring the expression levels of cardiomyocyte-specific genes using RT-qPCR. PIP3-primed cardiomyocytes were treated with 10 and 30 μmol/L of a 322PESB derivative molecule. The results showed a typical MSCs with high expression levels of CD73 (77.55%), CD90 (87.59%) and CD105 (91.88%) and that was accompanied by low expression levels of CD34 (0.59%) and CD45 (1.78%). After 21 days of MSC culture, cardiomyocyte-like cells with prominent striations were observed. Subsequent confirmation by RT-qPCR quantification of ADRB1 and MLC2a expression levels showed an average increase of 2.9-fold and 2.1-fold, respectively, in induced cardiomyocytes. Compared with the untreated control, PIP3 ELISA assay showed a significant increase in PIP3 levels in PIP3(10 nmol/L)-primed cardiomyocytes treated with 10 and 30 μmol/L of the 322PESB molecule derivative by 485.804 and 3564.164 ng/mL, respectively. In this study, we conducted the first promising molecular regulator with potential therapeutic implications for CTD patients. Further functional animal model and clinical phase studies are recommended.

Cardiomyocyte↗

PubMed2025

Ossifying Spindled and Epithelioid Tumor: A Novel Soft Tissue Tumor.

This investigation describes the clinicoradiologic, pathologic, and molecular features of a unique soft tissue tumor characterized by a peripheral shell of bone and composed of bland myoid spindle and epithelioid cells that are keratin-positive. Our study cohort consists of 6 men and 6 women, with a mean age of 32 years. The tumors arose in the extremities (n = 9) and proximal limb girdle (n = 3) and were equally distributed between deep and superficial soft tissues. Patients reported dull painless masses of several months to >10 years duration (mean: 2.9 years). Imaging demonstrated a complete or partial peripheral shell of bone that could extend centrally, and the tumor's mean size was 5.7 cm. Histologically, the tumors were composed of uniform, eosinophilic myoid spindled cells growing in sheets and intersecting fascicles, surrounded by mature lamellar and/or woven bone. Also present was an admixed component of intermediate-sized epithelioid cells with eosinophilic cytoplasm. Mitotic activity was consistently low. Immunohistochemistry showed strong multifocal staining for keratins, and 50% (5/10) showed focal staining for S100; however, all were negative for SMA, desmin, SOX10, ERG, and CD34. Genetic analysis by multiple targeted RNA sequencing panels was negative (n = 10); however, whole transcriptome sequencing (n = 8) revealed a recurrent and novel in-frame SRSF7::NFATC3 fusion in 4 tumors. Dual fluorescence in situ hybridization probes for SRSF7::NFATC3 successfully confirmed this fusion and identified a fifth case, which had not undergone whole transcriptome sequencing but was negative by a targeted RNA fusion panel. Methylation profiling (n = 8) demonstrated a shared epigenetic profile distinct from other entities. Clinical follow-up (n = 11) showed no evidence of recurrence after primary excision with a mean of 41.6 months. In summary, we describe a novel soft tissue tumor designated "ossifying spindled and epithelioid tumor" as a descriptive histologic term that also emphasizes its close radiologic mimic, ossifying fibromyxoid tumor. All cases have behaved in a benign fashion without recurrence following simple excision. Awareness of this entity is important, so that it can be distinguished from other neoplasms that have more aggressive biological potential.

Humans↗

PubMed2026

Single-cell vector copy number analysis of phenotypically defined long-term hematopoietic stem cells for gene therapy safety assessment.

Hematopoietic stem cell (HSC)-based gene therapy has emerged as a transformative approach for the treatment of genetic diseases; however, accurate evaluation of vector copy number (VCN) remains critical for ensuring safety. Conventional bulk VCN assays, including quantitative PCR (qPCR) and droplet digital PCR (ddPCR), do not resolve clonal heterogeneity and cannot identify rare high-VCN cells that may contribute disproportionately to insertional mutagenesis risk. Here, we developed an accessible single-cell VCN profiling method by combining fluorescence-activated cell sorting (FACS) of phenotypically defined long-term HSCs (Lineage- CD34+ CD38- CD90+ CD45RA- cells) with whole-genome amplification followed by conventional qPCR. This approach enabled resolution of VCN distributions at single-cell level using standard laboratory techniques. Notably, single-cell analysis revealed a high VCN tail that bulk VCN analysis could not resolve. Furthermore, in a humanized mouse transplantation model, single-cell VCN profiling demonstrated that overall VCN distributions could be analyzed after engraftment, although inter-donor and inter-mouse variability was observed. Collectively, this method provides a rapid, cost-effective, and phenotypically resolved strategy for assessing VCN heterogeneity in gene-modified HSCs. Single-cell VCN profiling offers complementary insights beyond conventional bulk assays and may enhance preclinical safety evaluation of gene and cell therapy products.

lentiviral vector↗

PubMed2026

Ultra-sensitive profiling of CRISPR-Cas off-target effects with Tracking-seq2.

Accurate detection of off-target activity in primary human cells is crucial for ensuring the safety of gene therapies, yet existing methods often lack sufficient sensitivity. To address this limitation, we develop Tracking-seq2, an advanced technology that integrates exogenous 5' → 3' exonuclease treatment and non-homologous end joining (NHEJ) pathway inhibitors with the original Tracking-seq. Tracking-seq2 exhibits enhanced sensitivity in profiling off-target sites of diverse genome editors-including Cas9, Cas12a, cytosine base editors (CBEs), adenine base editors (ABEs), and prime editors (PEs). Critically, Tracking-seq2 is directly applicable to clinically relevant primary human cell types, such as T cells and CD34+ hematopoietic stem and progenitor cells (HSPCs). Furthermore, our findings reveal that genomic variations drive distinct off-target heterogeneity across different individuals, highlighting the necessity for personalized safety assessment in clinical genome editing applications. Tracking-seq2 provides a robust platform for sensitive off-target detection in primary cells, with sensitivity comparable to or exceeding current state-of-the-art methods.

Humans↗

PubMed2026

Exa-cel in Children with Transfusion-Dependent β-Thalassemia or Sickle Cell Disease.

BACKGROUND: Exagamglogene autotemcel (exa-cel) is a cell therapy in which autologous CD34+ hematopoietic cells are engineered through ex vivo clustered regularly interspaced short palindromic repeats-Cas9 editing of the erythroid-specific enhancer region of BCL11A to express fetal hemoglobin. In phase 3 studies involving participants 12 to 35 years of age with sickle cell disease or transfusion-dependent β-thalassemia, exa-cel eliminated vaso-occlusive crises and the need for red-cell transfusions. METHODS: In two ongoing, phase 3, open-label, single-group studies, we evaluated exa-cel in children 5 to 11 years of age with transfusion-dependent β-thalassemia or sickle cell disease. Before exa-cel infusion, participants underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end points were transfusion independence for at least 12 consecutive months in children with transfusion-dependent β-thalassemia and freedom from severe vaso-occlusive crises for at least 12 consecutive months in children with sickle cell disease. RESULTS: A total of 15 children with transfusion-dependent β-thalassemia and 11 with sickle cell disease received exa-cel; median follow-up was 16.0 months (range, 2.2 to 32.1) and 16.9 months (range, 7.6 to 33.1), respectively. Of 8 children with transfusion-dependent β-thalassemia who were followed to at least 16 months, 8 were transfusion independent; the status of the remaining 7 was not yet evaluable. Of 8 children with sickle cell disease who were followed to at least 16 months, 8 were free of vaso-occlusive crises; the status of the remaining 3 was not yet evaluable. All the children had at least one grade 3 or 4 adverse event; 2 children with transfusion-dependent β-thalassemia had severe veno-occlusive liver disease that was assessed as being related to busulfan conditioning, 1 of whom died. CONCLUSIONS: Exa-cel therapy resulted in transfusion independence or freedom from severe vaso-occlusive crises in participants with transfusion-dependent β-thalassemia or sickle cell disease, respectively, who were followed for at least 16 months. All the participants had grade 3 or 4 adverse events. (Funded by Vertex Pharmaceuticals and CRISPR Therapeutics; CLIMB THAL-141 ClinicalTrials.gov number, NCT05356195; CLIMB SCD-151 ClinicalTrials.gov number, NCT05329649.).

Child↗

PubMed2025

Clinical characteristic of isolated thrombocytopenia in patients with bone marrow failure-related germline variants: a retrospective study from a single centre.

BACKGROUND: Immune thrombocytopenia (ITP) comprises the majority of thrombocytopenia. Some patients respond poorly to first-line ITP therapy or develop pancytopenia years later. Recent studies link heterozygous germline variants in acquired aplastic anemia (AA), yet their role in isolated thrombocytopenia carrying bone marrow failure-related germline variants (ITGV-BMFs) remains unclear. While whole-exome sequencing (WES) detects these variants, its cost limits routine use. This study compares prognosis and clinical features of isolated thrombocytopenia in patients with ITGV-BMFsand those with classic ITP. METHODS: The clinical data of patients diagnosed with ITGV-BMFs were retrospectively analyzed and compared with those of patients with classic ITP from August 2018 to February 2024. The baseline characteristics, genomic systematically background, previous treatment response as well as their follow-up outcomes were compared. RESULTS: Patients with ITGV-BMFs demonstrated earlier onset age (p < 0.001), lower bleeding scores and CD34%, along with elevated mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and reticulocyte (RET) counts (p < 0.001). Multivariate logistic regression analysis showed that the patients with ITGV-BMFs may possess distinct characteristics, including an earlier age at onset (p = 0.014) and lower bleeding score (p = 0.048). Notably, MCV and RET showed promising performance in receiver operating characteristic (ROC) curve analysis. During the follow-up period, 57.69% (15/26) ITGV-BMFs patients were further confirmed as aplastic anemia (AA, n = 13) or myelodysplastic syndrome (MDS, n = 2), with a median progression-free survival (PFS) of 7.25 years (p < 0.0001). CONCLUSION: ITGV-BMFs may be diagnosed early using elevated MCV and reticulocyte counts, a diagnostic approach that may lead to earlier intervention and improved prognosis.

Humans↗

PubMed2025

Engraftment and persistence of HBB base-edited hematopoietic stem cells in nonhuman primates.

Sickle cell disease (SCD) is caused by a single nucleotide change in the β-globin gene that adenine base editors can convert to the nonpathogenic Makassar β-globin variant. Here, we evaluated the long-term efficiency and off-target editing potential of autologous Makassar base editing in three rhesus macaques as a step toward human translation. Base editing of CD34+CD90+ hematopoietic stem cells (HSCs) at the Makassar locus reached greater than 60% efficiency using a bystander nucleotide as a proxy for the sickle cell target in cells from healthy macaques. No impact on myeloid and erythroid colony formation was seen, and clonal analysis revealed that >90% of HSCs were edited, >20% with biallelic editing. After transplantation of autologous gene-edited HSCs, all three macaques rapidly recovered neutrophils, red blood cells, and platelets with stable editing of 25.6%, on average, observed across nucleated blood cells. Similarly, the bone marrow stem cell compartment maintained over 20% of cells harboring mono- or biallelic edits. Off-target editing was assessed at over 900 candidate sites, with editing observed at eight sites, but no selection for or impact of these edits was observed throughout engraftment. These data support further translation of base editing of autologous HSCs for the treatment of patients with SCD.

Animals↗