This prospective phase 1 pilot study evaluated the safety and efficacy of GS001, an adeno-associated virus serotype 8 (AAV8)-based vector encoding B-domain-deleted factor VIII with exploratory assessment of prophylactic immunosuppression. Twelve adult severe hemophilia A participants were enrolled. Participants received GS001 at either 2×10¹² (low dose cohort) or 4×10¹² (high dose cohort) vg/kg following prophylactic treatment with prednisone alone or prednisone plus tacrolimus starting from one week before GS001 infusion. Median (range) follow-up was 156.0 (144.0-208.0) / 110.5 (104.0-130.0) weeks (2×10¹² / 4×10¹² vg/kg). Transgene expression peaked at 5-7 weeks post-infusion. In low dose cohort, at week 144.0, median (range) factor VIII activity was 5.6 (0.5-52.0) IU/dL (n = 6). In high dose cohort, at week 104.0, median (range) factor VIII activity was 42.7 (29.4-92.1) IU/dL (n = 6) and all six participants sustained factor VIII levels above 29 IU/dL. Both cohorts showed significant reductions in annualized bleeding rate and factor VIII consumption with grade 1-2 adverse events. Alanine aminotransferase elevations occurred in 3/6 and 5/6 low/high-dose participants and most were grade 1. The Single-cell RNA analysis demonstrated that the prednisone plus tacrolimus pretreatment effectively inhibited CD8+ T cell immune responses in both cohorts. Overall, GS001 infusion was safe and well-tolerated, achieving a significant increase in factor VIII level. Pre-treatment with glucocorticoids and tacrolimus may benefit by suppressing induced immune responses, thereby enhancing transgene expression without increasing the risk of infection. This study was registered at www.clinicaltrials.gov as # NCT04728841.

Chimeric antigen receptor (CAR) T-cell therapy has emerged as a promising treatment for hematological malignancies; however, its efficacy and safety remain challenging, particularly in the context of high tumor burden. High tumor load and substantial residual lesions significantly impair CAR T-cell function and exacerbate cytokine release syndrome (CRS). Here, we report the development of a novel dual cellular immunotherapy in which human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are co-administered with CD19 CAR T-cells. We demonstrated that this combination therapy enhances the anti-tumor efficacy of CD19 CAR T-cells under high tumor burden condition. In xenograft models of high tumor burden B-cell lymphoma, the dual cellular immunotherapy improved survival, mitigated myelosuppression, and preserved CAR T-cell expansion. Transcriptomic analysis of CAR T-cells revealed enrichment of the Th17 pathway in CAR T-cells, while single-cell RNA sequencing showed enhanced, particularly that of NK-like cytotoxic T lymphocytes characteristics which are associated with Th17 differentiation. Furthermore, in a CRS model, hUC-MSCs attenuate CRS severity by suppressing macrophage activity. Collectively, hUC-MSCs significantly enhance the anti-tumor capability of CD19 CAR T-cells under high tumor burden conditions by inducing CD8+ NK-like cytotoxic T lymphocytes through Th17 differentiation, while concurrently mitigating treatment-related side effects. Our study provides a novel therapeutic strategy to improve clinical outcomes in hematological malignancies.

Corticosteroid resistance is a major obstacle to the management of patients with primary immune thrombocytopenia (ITP), as the factors contributing to the variability in treatment response remain largely unknown. We analyzed a broad set of plasma protein biomarkers from patients who are corticosteroid-sensitive (CSp; n = 30), patients who are corticosteroid resistant (CRp; n = 26), and healthy controls (HCs; n = 25) using a 92-plex immunoassay from Olink Proteomics Technology. A total of 54 inflammation-related proteins demonstrated significant differences among the three groups. Twenty-seven biomarkers showed statistical differences between CSp and CRp. Machine learning-based feature selection identified four potential biomarkers, which were closely related to corticosteroid resistance: CXCL10, IL-1α, glial cell line-derived neurotrophic factor (GDNF), and CCL11. A Nomograph model was developed based on these 4 biomarkers, demonstrating remarkable discriminative ability, with an area under the curve (AUC) of 0.920 (95% confidence interval: 0.830-1.000) in this exploratory cohort. Although requiring external validation in larger studies, the identification of the four potential biomarkers suggested their value in predicting corticosteroid resistance in patients with newly diagnosed ITP, and might guide the initial choice of treatment.

BACKGROUND:Thrombotic thrombocytopenic purpura (TTP) is a rare but life-threatening thrombotic microangiopathy, with a substantial risk of relapse despite advances in therapy. Robust biomarkers to predict relapse are urgently needed to inform risk-adapted management. This study represents the first application of bone marrow proteomic profiling in TTP to explore relapse-associated biomarkers. OBJECTIVES:To identify clinical risk factors and novel protein biomarkers for relapse in TTP through integrated clinical and bone marrow proteomic analyses. METHODS:We conducted a retrospective cohort study involving 123 patients diagnosed with TTP at a single center. Clinical and laboratory variables at initial presentation were analyzed to identify potential predictors of relapse using Cox proportional hazards models. To explore molecular correlates of relapse, bone marrow paraffin-embedded samples from 18 patients were subjected to quantitative proteomic profiling. Machine learning algorithms were applied to identify candidate relapse-associated proteins. Selected proteins were subsequently validated by immunohistochemistry of corresponding tissue sections. RESULTS:Age ≤30 years and severe neuropsychiatric symptoms were independently associated with increased relapse risk, but demonstrated only moderate predictive performance (area under the curve = 0.706). Proteomic profiling revealed TMEM109 as a relapse-associated protein with superior discriminative capacity (area under the curve = 0.929). Immunohistochemistry analysis confirmed reduced TMEM109 expression in relapsed patients (P < .0001). CONCLUSION:TMEM109 is a promising biomarker for predicting TTP relapse. While clinical factors such as age and neuropsychiatric symptoms provide valuable prognostic information, TMEM109 may enhance relapse-risk stratification, offering potential for individualized monitoring and therapeutic decision-making. These findings underscore the value of proteomic profiling in complementing clinical evaluation in TTP.

Background:Immune thrombocytopenia is an autoimmune bleeding disorder. Daratumumab, a human monoclonal antibody targeting CD38 glycoprotein, is currently under clinical investigation as a potential therapy for autoimmune diseases. This trial aimed to evaluate the efficacy and safety of daratumumab in adults with immune thrombocytopenia. Methods:This single-center, open-label, phase 2 trial enrolled patients with a platelet count <30 × 109 platelets per L during the screening period. The study protocol comprised a 4-week screening phase, an 8-week treatment course, and a 16-week follow-up period. Daratumumab was administered intravenously at 16 mg/kg once weekly for eight consecutive weeks. The primary endpoint was defined as two or more consecutive platelet counts of at least 50 × 109 platelets per L within 8 weeks. This trial is registered at clinicaltrials.gov as #NCT05562882. Findings:Between December 10, 2022, and August 15, 2024, 63 patients were enrolled. All participants completed the full treatment and follow-up schedule. 52 patients (83%) reached the primary endpoint, with 46 (73%) having platelet counts of at least 50 × 109 platelets per L within the first week. At week 8, 49 patients (78%) had an overall response, including a complete response in 32 (51%). An overall response was observed in 38 patients (60%) at week 24. The proportion of patients with bleeding symptoms (WHO grade 1-4) declined from 44% (28 of 63) at baseline to 10% (6 of 63) at week 8. Infusion-related reactions were reported in 32% (20 of 63) of cases, primarily during the initial administration. Infections occurred in 32% (20 of 63) of patients, with upper respiratory tract infections accounting for 24% (15 of 63). Interpretation:These findings suggest that daratumumab could be a potential therapeutic option for adults with immune thrombocytopenia, with observations of rapid platelet recovery, durable responses, and an acceptable safety profile. Funding:The Noncommunicable Chronic Diseases-National Science and Technology Major Project, National Natural Science Foundation of China, CAMS Innovation Fund for Medical Sciences, National Key Research and Development Program of China, Tianjin Municipal Science and Technology Commission Grant, Joint Funds of the Natural Science Foundation of Tianjin, and China Higher Education Institution Industry-University-Research Innovation Fund.

Adeno-associated virus (AAV) vectors have demonstrated strong clinical efficacy across multiple monogenic disorders, yet neutralizing antibodies (NAbs) remain major barriers to vector redosing and durable transduction. To address this limitation, we developed a sequence-based artificial intelligence framework integrating Bidirectional Encoder Representations from Transformers (BERT) and Evolutionary Scale Modeling with Low-Rank Adaptation (ESM-LoRA) to identify human-tolerant, virus-specific motifs across human and viral proteins using sliding-window analyses and multi-layer fine-tuning. From AAV2 and AAV843 capsid-derived segments, we prioritized surface-accessible, virus-polarized peptides as candidate decoys and evaluated their ability to block AAV-targeted antibodies. The models achieved high accuracy in distinguishing human versus viral fragments, and selected peptides bound AAV-specific antibodies with nanomolar affinity, competitively restored capsid binding, and recovered >60% of baseline transduction in the presence of NAbs. In mouse models with pre-existing or redosing-induced antibodies, combined administration of decoy peptides and an IgG-degrading enzyme reduced high-titer NAbs to ∼1:4 and restored hepatic transgene expression without detectable inflammatory or peptide-specific immune responses. A contrastive Variational Autoencoder (VAE) further generated non-natural peptides with broader epitope coverage. These results support sequence-driven AI design of short, low-immunogenicity decoy peptides as a translational strategy to mitigate NAb interference and enhance the feasibility of AAV redosing.

Autoimmunity remains challenging to treat without broad immunosuppression. We previously showed that anti-CD38 antibody can rapidly elevate platelet counts in refractory immune thrombocytopenia (ITP), but the underlying mechanism was unclear. Here we report that anti-CD38 antibody induces platelet recovery within 3 days, including after retreatment in relapsed cases. Mechanistically, CD38-mediated nicotinamide adenine dinucleotide (NAD+) depletion drives M1-like macrophage polarization with increased Fc gamma receptor I (FcγRI) expression, thereby promoting macrophage phagocytosis of opsonized platelets. In mice, CD38 inhibition or nicotinamide mononucleotide (NMN) supplementation restores NAD+, reprograms macrophages, downregulates FcγRI and prevents thrombocytopenia. In an ovalbumin immunization model, NMN treatment does not impair antigen-specific antibody production, supporting preservation of humoral responses. Based on these findings, we conducted a single-arm, open-label phase 1/2 trial of low-dose oral NMN (450 mg twice daily for 2 weeks) in adults with steroid-refractory or steroid-dependent ITP. Primary endpoints were safety/tolerability and platelet response (≥50 × 109 per liter within 2 weeks, confirmed by two consecutive measurements one or more days apart, without rescue therapy or dose escalation of thrombopoietin receptor agonists or corticosteroids). Among 25 enrolled patients, no dose-limiting toxicities or treatment-related serious adverse events occurred; NMN was well tolerated, with only mild treatment-related adverse events in 12% and non-severe infections (grade 1) in 8% of patients while immunoglobulin levels remained stable, consistent with preserved humoral immunity. Five patients (20.0%) met the primary platelet-response endpoint. In exploratory analyses, overall, 60% of patients achieved platelet counts more than 1.5× baseline during treatment, and 52% maintained responses through week 8. Together, these data identify the CD38-NAD+ axis as an immunometabolic checkpoint in ITP and support further exploration of NMN as a non-antibody-depleting metabolic strategy for antibody-mediated disease. ClinicalTrials.gov identifier: NCT06776510 .

AIMS:To define JAK2v617f-induced immune alterations, focusing on STAT3-mediated dendritic cell dysfunction, and evaluate whether IFNα2b restores anti-tumor immunity in JAK2v617f-positive myeloproliferative neoplasms. METHODS:Integrated flow cytometry and single-cell RNA sequencing profiled immune landscapes and signaling pathways, while functional assays assessed dendritic cell differentiation, T cell activation, and IFNα2b-mediated immune restoration. RESULTS:JAK2v617f was associated with increased STAT3 activation in myeloid cells, accompanied by elevated expression of immunosuppressive mediators such as FGL2, impaired monocyte-to-DC differentiation, reduced cDC1/cDC2 subsets, and diminished T cell activation, consistent with an immunosuppressive immune landscape. IFNα2b treatment was associated with attenuation of STAT3/FGL2 signaling and partial restoration of DC-mediated T cell priming, with more pronounced immunomodulatory effects observed in JAK2v617f-positive myeloproliferative neoplasms compared with other subtypes. CONCLUSIONS:Our findings indicate that JAK2v617f is associated with STAT3-dependent dendritic cell dysfunction that contributes to an immunosuppressive milieu. IFNα2b modulates this pathway and partially restores DC-T cell interactions, highlighting its potential as an immunomodulatory strategy in JAK2v617f-positive myeloproliferative neoplasms.

Lentiviral vectors are widely used for stable gene delivery, but their transduction efficiency can be limited by suboptimal experimental conditions. Here, we investigated the role of oxygen concentration and hypoxia-inducible factor 1 (HIF-1) signaling in lentiviral packaging and transduction. We found that packaging lentivirus under hypoxic conditions (10% O₂) significantly increased viral titers and transduction efficiency by approximately 10%. However, hypoxic conditions during viral entry impaired infection efficiency, likely due to HIF-1α-mediated cellular protective mechanisms. Pretreatment of cells with the HIF-1 inhibitor PX-478 reversed this effect, enhancing viral entry and genome integration in a dose-dependent manner. Combining hypoxic virus packaging with PX-478 pretreatment synergistically improved transduction efficiency by 20%. These findings suggest that HIF-1 inhibition and controlled hypoxia significantly enhance lentiviral transduction efficiency, establishing a versatile strategy with broad applicability across viral vector-dependent biomedical applications.

OBJECTIVE:To assess the efficacy and safety of CM313, an anti-CD38 monoclonal antibody, in adults with persistent or chronic primary immune thrombocytopenia. DESIGN:Multicentre, randomised, placebo controlled, phase 2 trial. SETTING:Five hospitals in China, 16 January to 11 June 2024. PARTICIPANTS:45 patients aged ≥18 years with persistent or chronic immune thrombocytopenia who failed to respond to, or relapsed after, glucocorticoid treatment but had previously responded to standard first line treatment. INTERVENTIONS:Patients were randomised to receive intravenous CM313 (16 mg/kg) or placebo weekly for eight weeks. MAIN OUTCOME MEASURES:The primary outcome was overall response rate (at least two consecutive platelet counts ≥30×109/L, a minimum doubling from baseline, and no bleeding) at week 8. A secondary outcome was time to the first two consecutive platelet counts ≥50×109/L. RESULTS:Of 56 patients screened, 45 were randomised to receive CM313 (n=30) or placebo (n=15). At week 8, the overall response rate was higher in the CM313 group (83%; 25/30) compared with placebo group (20%; 3/15): difference 63.3% (95% confidence interval 33.7% to 81.3%; P<0.001). The median time to a platelet count of ≥50×109/L was one week in the CM313 group but was not reached in the placebo group (P<0.001). The median cumulative response duration for platelet counts ≥50×109/L was 18 weeks in the CM313 group versus three weeks in the placebo group (P=0.004). Treatment emergent adverse events occurred in 87% (26/30) of patients in the CM313 group and 80% (12/15) in the placebo group, with infusion related reactions and petechiae being the most common. CONCLUSION:CM313 showed a favourable safety profile and encouraging efficacy in adults with persistent or chronic primary immune thrombocytopenia, characterised by rapid increase in platelet count, sustained platelet responses, and manageable adverse events. TRIAL REGISTRATION:ClinicalTrials.gov NCT06199089.

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Supplementary Table S2. Targeted 267-gene panel for next-generation sequencing.

Background: Male sex has been confirmed as an independent risk factor on survival effect in patients withessential thrombocythemia by mutation-enhanced international prognostic scoring system for essential thrombocythemia (MIPSS-ET) (Tefferi A, et al., Br J Haematol. 2020). Females are more common in ET patients (Grinfeld, et al., N Engl J Med. 2018). Epigenetic alterations (EAs) are found in approximately 20% inET. However, the prognostic role of epigenetic alterations is still not established in this patient population. Sexual dimorphism significantly contributes to patient heterogeneity, and adopting a sex-informed perspective has emerged as a pioneering paradigm in the field of precision medicine. The objective of our study was to comprehensively elucidate the impact of sex diversity on essential thrombocythemia, encompassing disease genotype, phenotype, and clinical outcomes. Methods: In this study, we performed retrospective chart review of 556 consecutive patients aged 18 years or older with a diagnosis of essential thrombocythemia according to the 5 th World Health Organization classification of myeloid neoplasms (Khoury JD, et al., Leukemia. 2022). Recruitment periods for these patients were between January 2008 to June 2022. Overall survival (OS) from the time of diagnosis was estimated by Kaplan-Meier method with log-rank test. The effect of sex on clinical outcome, with OS, myelofibrosis-free survival, and thrombosis-free survival as the main endpoint, was analyzed in our cohort. Results: This study included 245 (44.1%) men and 311 (55.9%) women. The percentages of age>60 years at diagnosis were 26.1% for men and 21.2% for women (p=0.176). Patients in the women cohort had lower red blood cell levels (4.54 vs. 4.81, p<0.001), lower hemoglobin levels (135 g/L vs. 146 g/L, p<0.001), lower percentage of cardiovascular risk factor (21.8% vs. 39.3%, p<0.001), and lower percentage of abnormal karyotype (37.3% vs. 50.6%, p=0.009). The treatment distributions between men and women cohorts were comparable ( p>0.05). Sex biases were observed at the single-gene level with mutation in two genes enriched in males (SF3B1 p=0.008, ZRSR2 p=0.024). The ASXL1 gene mutation exhibited a discernible inclination towards a higher prevalence in males (p=0.098). Additionally, sex biases were observed in co-mutational pathways of founding genomic lesions (genes related to spliceosome mutation (SM), predominantly in men, p<0.001). Patients with SM had inferior OS and myelofibrosis-free survival than those without SM (p=2e-04, p=0.0078). Sex disparity was observed in the transcriptome signature of bone marrow CD34+ cells from ET patients. From results of GO analysis, we observed that up-regulated differentially expressed genes in male patients were significantly associated with the unfolded protein signaling pathway, as well as dysregulation of hematopoietic differentiation. Moreover, we found that lipid and atherosclerosis, and platelet activation pathways were enriched in male patients by KEGG analysis. Based on our analysis, we hypothesize that male ET patients exhibit enhanced bone marrow megakaryocyte production and platelet activation compared to female patients. Overall, Men had worse OS and thrombosis-free survival than women (both of median survival not reached; p=0.0081, p=0.019, respectively), but the myelofibrosis-free survival was not significantly different between men and women (p=0.52). Conclusions : The findings from our study indicate that the implementation of a sex-informed approach has the potential to enhance the precision of personalized decision making in individuals diagnosed with essential thrombocythemia. Therefore, it is imperative to incorporate this approach in the planning and execution of clinical trials in the future.

This study aimed to identify key proteomic analytes correlated with response to splenectomy in primary immune thrombocytopenia (ITP). Thirty-four patients were retrospectively collected in the training cohort and 26 were prospectively enrolled as validation cohort. Bone marrow biopsy samples of all participants were collected prior to the splenectomy. A total of 12 modules of proteins were identified by weighted gene co-expression network analysis (WGCNA) method in the developed cohort. The tan module positively correlated with megakaryocyte counts before splenectomy (r = 0.38, p = 0.027), and time to peak platelet level after splenectomy (r = 0.47, p = 0.005). The blue module significantly correlated with response to splenectomy (r = 0.37, p = 0.0031). KEGG pathways analysis found that the PI3K-Akt signalling pathway was predominantly enriched in the tan module, while ribosomal and spliceosome pathways were enriched in the blue module. Machine learning algorithm identified the optimal combination of biomarkers from the blue module in the training cohort, and importantly, cofilin-1 (CFL1) was independently confirmed in the validation cohort. The C-index of CFL1 was >0.7 in both cohorts. Our results highlight the use of bone marrow proteomics analysis for deriving key analytes that predict the response to splenectomy, warranting further exploration of plasma proteomics in this patient population.

PURPOSE:Triple-negative (TN) essential thrombocytopenia (ET) is characterized by the absence of driver mutations while retaining histologic and phenotypic characteristics sufficient for an ET diagnosis. Our understanding of TN-ET and its platelet activation remains incomplete. We carried out a large-scale multicenter clinical analysis to analyze the clinical and molecular characteristics and thrombotic complications of TN-ET. We also related the above characteristics to platelet activation to further explore the thrombosis mechanism of TN-ET. EXPERIMENTAL DESIGN:A retrospective multicenter study was conducted on 138 patients with TN-ET and 759 patients with ET with driver mutations from March 1, 2012 to December 1, 2021. The clinical and molecular characteristics of the patients with TN-ET were summarized. Additionally, platelet activation, apoptosis, and reactive oxygen species (ROS) levels were analyzed in 73 patients with TN-ET from this cohort and compared with 41 age- and sex-matched healthy donors. RESULTS:Compared with patients with the JAK2V617F mutation, those with TN mutation were younger (P < 0.001) and exhibited fewer thrombotic events before diagnosis (P < 0.001) and during follow-up (P = 0.039). Patients with TN mutation also presented with significantly reduced CD62P expression in platelets (P = 0.031), slightly reduced calcium concentration in platelets (P = 0.063), increased mitochondrial membrane potential (P = 0.011), reduced phosphatidylserine exposure (P = 0.015), reduced levels of ROS (P = 0.043) and MitoSOX in platelets (P = 0.047). CONCLUSIONS:In comparison with JAK2V617F-mutated ET, TN-ET is associated with lower platelet ROS levels, which leads to reduced platelet activation and consequently a lower risk of thrombosis.

Primary immune thrombocytopenia (ITP) is an autoimmune bleeding disorder, and chemokines have been shown to be dysregulated in autoimmune disorders. We conducted a prospective analysis to identify potential chemokines that could enhance the diagnostic accuracy and bleeding evaluation in ITP patients. In the discovery cohort, a Luminex-based assay was employed to quantify concentrations of plasma multiple chemokines. These levels were subjected to comparative analysis using a cohort of 60 ITP patients and 17 patients with thrombocytopenia other than ITP (non-ITP). Additionally, comparative evaluation was conducted between a subgroup of 12 ITP patients characterised by bleeding episodes (ITP-B, as defined by an ITP-2016 bleeding grade ≥2) and 33 ITP patients without bleeding episodes (ITP-NB, as defined by an ITP-2016 bleeding grade ≤1). Machine learning algorithms further identified CCL20, interleukin-2, CCL26, CCL25, and CXCL1 as promising indicators for accurate diagnosis of ITP and CCL21, CXCL8, CXCL10, CCL8, CCL3, and CCL15 as biomarkers for assessing bleeding risk in ITP patients. The results were confirmed using enzyme-linked immunosorbent assays in a validation cohort (43 ITP patients and 19 non-ITP patients). Overall, the findings suggest that specific chemokines show promise as potential biomarkers for diagnosis and bleeding evaluation in ITP patients.

Following adeno-associated virus (AAV) gene therapy, administering immunosuppressants can enhance therapeutic efficacy by suppressing induced immune responses. GS001, a novel vector constructed with AAV8 and a liver-specific expression cassette for B domain-deleted factor VIII (FVIII), was evaluated in an open-label, phase 1 dose-escalation pilot study (NCT04728841) with 12 adult severe haemophilia A (HA) patients. Patients received either 2×10¹² or 4×10¹² vector genomes (vg)/kg of GS001 following one-week prophylactic treatment with prednisone alone or with tacrolimus. Median follow-up was 123.5/58.5 weeks (2×10¹²/4×10¹² vg/kg). Transgene expression peaked at 5-7 weeks post-infusion. At week 52, mean (±SD) FVIII activity (FVIII:C) levels were 14.6 ± 20.2 IU/dL (2×10¹² vg/kg) and 71.0 ± 24.0 IU/dL (4×10¹² vg/kg). Both groups showed significant reductions in annualized bleeding rate and FVIII consumption with grade 1-2 adverse events. Prophylactic prednisone and tacrolimus increased FVIII expression in the 2×10¹² vg/kg group. Immune responses, including AAV8-specific interferon-secreting T cells and antibodies, did not differ between dose groups. Single-cell RNA sequencing of peripheral blood immune cells before and after infusion revealed major inflammatory pathways not activated in CD8+ T cells in either dose group, while interferon-α-related genes exhibited a slight increase. Tacrolimus effectively inhibited patient-derived activated CD8+ T cell proliferation in vitro. Overall, GS001 infusion was safe, well-tolerated, achieving a significant and durable increase in FVIII. Pre-treatment with glucocorticoids and tacrolimus may benefit by suppressing induced immune responses, thereby enhancing sustained transgene expression.

Patients with refractory immune thrombocytopenia (ITP) frequently encounter substantial bleeding risks and demonstrate limited responsiveness to existing therapies. Umbilical cord-derived mesenchymal stem cells (UC-MSCs) present a promising alternative, capitalizing on their low immunogenicity and potent immunomodulatory effects for treating diverse autoimmune disorders. This prospective phase I trial enrolled eighteen eligible patients to explore the safety and efficacy of UC-MSCs in treating refractory ITP. The research design included administering UC-MSCs at escalating doses of 0.5 × 106 cells/kg, 1.0 × 106 cells/kg, and 2.0 × 106 cells/kg weekly for four consecutive weeks across three cohorts during the dose-escalation phase, followed by a dose of 2.0 × 106 cells/kg weekly for the dose-expansion phase. Adverse events, platelet counts, and changes in peripheral blood immunity were monitored and recorded throughout the administration and follow-up period. Ultimately, 12 (with an addition of three patients in the 2.0 × 106 cells/kg group due to dose-limiting toxicity) and six patients were enrolled in the dose-escalation and dose-expansion phase, respectively. Thirteen patients (13/18, 72.2%) experienced one or more treatment emergent adverse events. Serious adverse events occurred in four patients (4/18, 22.2%), including gastrointestinal hemorrhage (2/4), profuse menstruation (1/4), and acute myocardial infarction (1/4). The response rates were 41.7% in the dose-escalation phase (5/12, two received 1.0 × 106 cells/kg per week, and three received 2.0 × 106 cells/kg per week) and 50.0% (3/6) in the dose-expansion phase. The overall response rate was 44.4% (8/18) among all enrolled patients. To sum up, UC-MSCs are effective and well tolerated in treating refractory ITP (ClinicalTrials.gov ID: NCT04014166).

Abstract The causal direction and extent of the link between telomere length, epigenetic age acceleration (EAA), and the occurrence of haematological malignancies and benign haematological disorders remain uncertain because of the inherent susceptibility of observational studies to confounding and reverse causation. We conducted two-sample single-variable Mendelian randomisation (SVMR) and multivariable Mendelian randomisation (MVMR) analyses using summary statistics from genome-wide association studies (GWAS) to explore potential associations among telomere length, EAA, and multiple haematologic diseases. We employed an independent validation dataset and utilised various Mendelian randomisation (MR) methods with distinct model assumptions to verify the validity of our findings. Additionally, we performed MVMR analysis based on Bayesian model averaging (MVMR-BMA) to determine whether telomere length, in isolation from EAA, was the true causal factor in the development of haematologic diseases. We obtained 59 GWASs on haematologic diseases from FinnGen, with 182–27,371 cases and 88,536– 376,651 controls. Increased telomere length due to germline genetic variation was generally associated with an increased risk for 10 of 21 haematological malignancies. Genetically predicted telomere length and EAA were not directly associated with the risk of nearly all benign haematological disorders. MVMR-BMA analysis showed that telomere length had the strongest association with the risk of haematologic diseases compared with the five EAA.Our study outcomes suggest the plausibility of potential clinical applications of telomere length, such as serving as a valuable risk prediction tool or as a targeted intervention for the prevention of haematologic diseases.

Supplementary Figure S2. Platelet CD62P expression and phosphatidylserine exposure of TN-ET platelets after ROS inhibition.