Abstract Sequential changes in transcriptional cell state are essential for normal development and are coopted in cancer. Controlling these changes for therapeutic benefit has been limited due to a lack of tools that reflect different states in live cells. Here, we describe a new reporter method termed “TRECS” that integrates epigenomic and transcriptomic measurements to define endogenous genomic elements that label individual cells in different cell states. We use TRECS in the neural crest-derived, high-risk pediatric solid tumor neuroblastoma, where we demonstrate broad presence of cells with distinct transcriptomes, associated with functional chemoresistance and sensitivity. Experiments using neural crest stem cells and TRECS mouse knock-in model identified that TRECS-labelled cells reflect early developmental stages in the neural crest. These cells display real-time plasticity of transcriptional state and phenotype, in a manner unlinked to cell cycle control. Investigation of nominated loci demonstrates state-specific enrichment of elements marked by H3K27ac, H3K4me1 and open chromatin by ATAC-seq, which flexibly change as cells transition between these phenotypically divergent states. To investigate whether the primary nominated locus is a driver or reporter of cell state, we integrate micro-C, transcriptomics, truncation experiments and functional CRISPRi to identify that this region functions as a pure endogenous reporter of cell state. This, therefore, provides a mechanism to identify new, state-controlling transcription factors. Motif analysis demonstrated enrichment of AP1 transcription factor motifs in the chemoresistant state, and knockout of these AP1 transcription factors results in rewiring of cell state and enhanced chemosensitivity without effects on cell growth. To capitalize on the endogenous flexibility in this system and identify mechanisms to enforce cell state changes independent of cell growth and death, we performed high-content image-based small molecule screening to identify targets suitable to enhance chemosensitivity. These experiments identified EP300/CBP, master histone acetyltransferases, as crucial controllers of a primitive, chemoresistant cell state. Transient acetyltransferase and bromodomain-based inhibition of EP300/CBP results in transcriptional and epigenetic reprogramming in vitro and in vivo, leading to enhanced chemosensitivity and prolonged survival in murine models. These results demonstrate an unbiased method to identify non-coding genomic loci enriched in specific cell states, which can be harnessed to identify master transcription factors driving these cell states and similarly, mechanisms to enforce changes in cell state. Citation Format: Noha Shendy, Yang Zhang, Stephanie Nance, Ha Won Lee, Shivendra Singh, Yousef Khashana, Vernon Ebegboni, Estevez Prado Daniel, Mohammad Ali Mohammad Nezhady, K. Elaine Ritter, Anoop Kavirayani, Bensheng Ju, Grace McKay-Corkum, Qi Liu, Yiping Fan, Gang Wu, Jun Qi, John B. Easton, Anand G. Patel, JUN YANG, Taosheng Chen, Brian Abraham, Adam D. Durbin. A genome derived non coding reporter of dynamic cancer cell state [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 385.

Abstract Introduction Asparaginase (ASNase) is a crucial component of pediatric acute lymphoblastic leukemia (ALL) combination chemotherapy. However, its use is complicated by hypersensitivity reactions that necessitate switching from Escherichia coli-derived ASNase to Erwinia chrysanthemi ASNase to maintain therapy. While most hypersensitivity cases can be avoided by switching formulations, a subset of patients develop allergic responses to both. The role of ASNase-specific T cell responses in the development of ASNase hypersensitivity is poorly defined, and no bona fide ASNase-specific T cell receptors (TCR) have been identified. Methods We analyzed a large bulk TCR sequencing dataset of ALL patients with and without ASNase allergy and identified single chains significantly associated with allergy. To identify paired TCRs specific for ASNase, we deployed a novel, high-throughput, paired TCR sequencing method (TIRTL-Seq) on additional ALL patient samples with allergy and compared sequence features to the allergy-associated single chains. Results This yielded a list of candidate paired TCRs, 8 of which have been stably transduced into reporter cell lines for use in peptide library screens to validate their specificity and characterize their epitope recognition. Conclusion Understanding the T cell responses in ASNase hypersensitivity will provide insight into drug induced allergic responses and lay the foundation for optimization of ASNase formulations with reduced immunogenicity. Funding Source St. Jude Graduate School of Biomedical Sciences Topic Categories Translational and Interventional Immunology (TI)

Rhabdomyosarcoma (RMS) is a malignant tumor originating from skeletal muscle precursor cells and is the most common soft tissue sarcoma in children. RMS is classified histologically as embryonic (ERMS) or alveolar (ARMS). ARMS is generally more aggressive and has poorer outcomes. ARMS is mainly driven by oncogenic fusion proteins Pax3::Foxo1 (P3F1) or Pax7::Foxo1 (P7F1). SOX8, a transcription factor essential for embryonic development, is highly expressed in embryonic skeletal muscle but decreases as development advances. SOX8 plays a vital role in the survival of ARMS by maintaining muscle cells in a less differentiated state. P3F1 enhances SOX8 expression via super-enhancers. Our preliminary data indicate that, in the presence of T025, a Cdc2-like kinase (CLK) inhibitor, SOX8 undergoes mRNA mis-splicing, leading to the loss of normal SOX8 protein function. ARMS cell lines (RH30/RH4) were plated in six-well plates and allowed to adhere for 24 hours before treatment with different concentrations of T025 (0, 12, 37, 111, 333, and 1000 nm) for 48 hours. After treatment, cells were harvested and analyzed for changes in protein and RNA. Western blotting measured levels of SOX8, CLK2, MYOD1, and FOXO1 proteins. Total RNA was converted to cDNA to identify alternative splicing events in SOX8 mRNA. Western blot analysis of both RH30 and RH4 shows a dose-dependent decrease in the expression of the SOX8 protein as T025 concentrations increase. Additionally, a reduction in the expression of MYOD1 and FOXO1 proteins was observed with higher doses. CLK2 protein levels were also suppressed with increasing T025 doses, confirming its activity. While both cell lines exhibited a dose-dependent response, RH4 appeared to be more significantly affected. Subsequent PCR analysis of RH30 cells treated with T025 revealed the presence of a mis-spliced isoform containing intronic sequences in exon 2, consistent with our RNA-seq data. Our findings reveal that CLK2 inhibition via T025 causes mis-splicing in the mRNA of the SOX8 in alveolar rhabdomyosarcoma. This results in reduced SOX8 protein levels and downregulation of other key proteins involved in rhabdomyosarcoma survival, impairing tumor proliferation and survival. This discovery further supports the idea that CLK inhibition is a promising target for future studies to disrupt mRNA splicing in ARMS. Vincent A. Terta, Qiong Wu, Jun Yang. CLK inhibition induces mis-splicing of SOX8 in alveolar rhabdomyosarcoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Fusion-Positive Cancer: From Discovery to Therapy; 2026 Jan 13-15; Philadelphia PA. Philadelphia (PA): AACR; Cancer Res 2026;86(1_Suppl):Abstract nr A021.

Importance:CD19-directed chimeric antigen receptor (CAR) T-cell therapy induces high remission rates in relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL), but relapse, which is often due to antigen loss, remains a major challenge. Dual-targeting CD19/CD22 CAR T-cell strategies may be associated with reduced antigen-negative relapse and improved remission durability. Objective:To evaluate the safety and efficacy of bicistronic CD19/CD22 CAR T-cell therapy in pediatric patients with relapsed or refractory B-ALL. Design, Setting, and Participants:This open-label, multicenter, phase 2 nonrandomized clinical trial enrolled pediatric patients with B-ALL at 5 major medical centers in China from January 2022 to August 2024, with a data cutoff of February 28, 2026. Median follow-up was 35.7 months (IQR, 29.8-41.0 months). Of 346 screened, 38 (11.0%) were excluded and 308 (89.0%) were eligible. A safety run-in established the recommended phase 2 dose, followed by cohorts with refractory disease, hematologic relapse, or isolated extramedullary relapse. Intervention:CD3-positive T cells were activated and transduced with a bicistronic lentiviral vector that encoded anti-CD19 and anti-CD22 CARs, then infused fresh after 5 to 7 days in culture. Lymphodepleting chemotherapy included fludarabine and cyclophosphamide. Consolidative transplant was reserved for patients with KMT2A- or ZNF384-rearranged acute lymphoblastic leukemia. Main Outcomes and Measures:Primary end points were safety, recommended phase 2 dose, event-free survival (EFS), and toxic effects of bicistronic CAR-T therapy in relapsed or refractory B-ALL, with or without transplant. Results:Among 261 patients (98 girls [37.6%]; mean [SD] age, 8.2 [3.8] years) with relapsed or refractory disease, 259 (99.2%) achieved complete remission with negative minimal residual disease. EFS was 70.9% (95% CI, 65.6%-76.7%) at 12 months, 63.2% (95% CI, 57.6%-69.4%) at 24 months, and 61.7% (95% CI, 55.9%-68.0%) at 36 months. Consolidative transplant was associated with improved EFS; the 24-month EFS was 57.9% (95% CI, 51.6%-65.0%) in patients without a transplant vs 85.7% (95% CI, 76.5%-96.1%) in patients with a transplant (P = .004). In 20 patients with isolated central nervous system relapse and 20 with testicular relapse, 24-month EFS was 60.0% (95% CI, 43.6%-82.6%) and 80.0% (95% CI, 64.3%-99.6%), respectively. Grade 3 to 4 cytokine release syndrome occurred in 129 patients (49.4%), and immune effector cell-associated neurotoxic effects occurred in 34 patients (13.0%). Conclusions and Relevance:In this nonrandomized clinical trial, bicistronic CD19/CD22 CAR T-cell therapy induced high rates of minimal residual disease-negative remission, with durable EFS in pediatric B-ALL. These findings support further evaluation in prospective trials. Trial Registration:Chinese Clinical Trial Register Identifier: ChiCTR2000032211.

3D cellular-specific epigenetic and transcriptomic reprogramming is critical to organogenesis and tumorigenesis. Here, we dissect the distinct cell fitness in 2D (normoxia vs. chronic hypoxia) vs 3D (normoxia) culture conditions for an MYC-driven murine liver cancer model. We identify over 600 shared essential genes and additional context-specific fitness genes and pathways. Knockout of the VHL-HIF1 pathway results in incompatible fitness defects under normoxia vs. 1% oxygen or 3D culture conditions. Moreover, deletion of each of the mitochondrial respiratory electron transport chain complex has distinct fitness outcomes. Notably, multicellular organogenesis signaling pathways including TGFβ-SMAD, which is upregulated in 3D culture, specifically constrict the uncontrolled cell proliferation in 3D while inactivation of epigenetic modifiers ( Bcor , Kmt2d , Mettl3, and Mettl14 ) has opposite outcomes in 2D vs. 3D. We further identify a 3D-dependent synthetic lethality with partial loss of Prmt5 due to a reduction of Mtap expression resulting from 3D-specific epigenetic reprogramming. Our study highlights unique epigenetic, metabolic, and organogenesis signaling dependencies under different cellular settings.

Bacterial endophthalmitis is an ophthalmological emergency that can lead to permanent blindness, and high-efficiency therapeutic strategies that can completely eradicate pathogens within a short timeframe are needed. However, intrinsic limitations of this disease, such as low administration frequency and dosage, render most currently available nano-antibacterial strategies inapplicable. To address this challenge, a bio-targeted catalytic strategy that is based on a bacteria-specific artificial biocatalyst (MoS2/Fe@mercaptophenylboronic acid@hyaluronic acid, MFBH) and suitable for treating bacterial endophthalmitis is proposed. The results show that MFBH exhibits high-efficiency peptidoglycan-targeted catalytic antibacterial capacity against both standard and clinically isolated strains of Staphylococcus aureus. Notably, the in vivo results demonstrate that MFBH achieves effective treatment of bacterial endophthalmitis at an extremely low dose (≈4 µg kg-1) via a single intravitreal injection without causing retinal damage. Importantly, the therapeutic efficacy of MFBH is comparable to that of vancomycin. Mechanistic analysis reveals that MFBH induces enhanced ferroptosis-like bacterial killing by accelerating reactive oxygen species (ROS) burst. Further investigations show that the generation of abundant ROS is closely associated with the sulfur vacancies and exposed of reactive Mo4+ on the surface of the prepared artificial biocatalyst. In summary, this bacteria-specific artificial biocatalyst provides a promising strategy for treating endophthalmitis.

Neuroblastoma accounts for approximately 15% of all pediatric cancer-related deaths, largely due to disease relapse following intensive multimodal therapy. A critical barrier to cure neuroblastoma is the emergence of therapy-resistant tumor cells. Neuroblastoma comprises two major cell states, adrenergic (ADRN) and mesenchymal (MES), which are believed to interconvert and contribute to therapeutic resistance through lineage plasticity. To investigate the mechanisms underlying this plasticity, we subjected human and murine neuroblastoma models to repeated treatment with indisulam, a molecular glue compound that selectively degrades the splicing factor RBM39, until full drug resistance emerged. We then generated datasets from these models, including bulk transcriptomic data, ATAC-seq, and H3K27ac CUT&Tag. These data comprehensively characterize transcriptomic and epigenetic landscapes of resistant ADRN and MES neuroblastoma cell states. We present this resource to facilitate reuse by the scientific community. These datasets may support efforts to decipher lineage switching, identify regulators of therapy resistance, and discover potential therapeutic vulnerabilities in resistant neuroblastoma.

Objectives: High-dose methotrexate (HDMTX) and asparaginase (ASP) play crucial roles in the multi-agent chemotherapy used to cure children with acute lymphoblastic leukemia (ALL). Individualized dosing of HDMTX based on its pharmacokinetics has the potential to improve efficacy and reduce toxicity. While a few predictors of HDMTX pharmacokinetics, such as SLCO1B1, are recognized, the impact of concomitant chemotherapy agents, such as ASP, and other genetic variations are not well-established.Methods: A cohort of 302 standard/high-risk (SR/HR) patients, aged 1 to 18 years old, with newly diagnosed ALL participated in the Total XVII trial at St. Jude Children’s Research Hospital (NCT03117751). During the consolidation phase, SR/HR patients received HDMTX every 2 weeks for 4 courses with a first dose of 5g/m2 and subsequent doses pharmacokinetically guided to target a steady-state plasma concentration of 65 µM. Prior to December 2019, they also received 1000 units/m2 of PEG-asparaginase (PEG-ASP) on day 3 of each HDMTX cycle pending clearance of methotrexate (MTX). After December 2019, PEG-ASP was removed from the consolidation phase.Serial blood samples for HDMTX pharmacokinetics monitoring were collected pre-infusion and at 6, 23, and 42-hours after the start of infusion. MTX population pharmacokinetics were estimated using nonlinear mixed-effects models implemented in Monolix using the Stochastic Approximation Expectation-Maximization method. A linear two-compartment model was used to fit the data. Parameters estimated were clearance, volume, intercompartmental clearance, and volume of the peripheral compartment. Whole-genome sequencing was also available. Results: There were 302 SR/HR patients with 1088 evaluable cycles of HDMTX, of which 220 were given when the patient was exposed to PEG-ASP. HDMTX clearance was 14% (p=9.1x10-12) lower when given with PEG-ASP, with a post-hoc median clearance of 76.9 vs 98.2 mL/min/m2. Due to the pharmacokinetic targeting of HDMTX, the median HDMTX dose given during consolidation cycles 2-4 was significantly lower in those who received concomitant PEG-ASP compared to those who did not (3.56 g/m2 vs 4.02 g/m2; p=0.047).HDMTX clearance was 8.9% (p=6.1x10-3) lower in those with SLCO1B1 decreased or poor function compared to those with normal or increased function (post-hoc median clearance: 83.3 vs 94.7 mL/min/m2). There was no significant interaction between SLCO1B1 phenotype and PEG-ASP exposure on HDMTX clearance (p=0.38).Conclusions: Our results indicate that PEG-ASP administered with HDMTX alters the pharmacokinetics of HDMTX by reducing its clearance. Due to this clinically significant interaction, protocols should be designed to avoid concurrent administration of HDMTX with PEG-ASP to avoid excessive toxicity. Further investigation is needed to determine the mechanism of this drug interaction and the potential effects of variants in genes other than SLCO1B1.Citations: N/A

Genomic alterations of IKZF1 are common and associated with adverse clinical features in B-ALL. The relationship between the type of IKZF1 alteration, disease subtype and outcome are incompletely understood. Leukemia subtype and genomic alterations were determined using transcriptome and genomic sequencing and SNP microarray in 688 pediatric patients with B-ALL in St. Jude Total Therapy 15 and 16 studies. IKZF1 alterations were identified in 115 (16.7%) patients, most commonly in BCR::ABL1 (78%) and CRLF2-rearranged, BCR::ABL1-like B-ALL (70%). These alterations were associated with 5-year cumulative incidence of relapse (CIR) of 14.8 ± 3.3% compared to 5.0 ± 0.9% for patients without any IKZF1 alteration (P < 0.0001). IKZF1 deletions of exon 4-7 (P = 0.0002), genomic IKZF1plus with any IKZF1 deletion (P = 0.006) or with focal IKZF1 deletion (P = 0.0007), and unfavorable genomic subtypes (P < 0.005) were independently adversely prognostic factors. Associations of genomic IKZF1plus and exon 4-7 deletions with adverse outcomes were confirmed in an independent cohort. Genomic IKZF1plus with any IKZF1 deletion, IKZF1 deletion of exon 4-7, and unfavorable subtype confer increased risk of relapse. The type of IKZF1 alteration, together with the subtype, are informative for risk stratification and predict response in patients with B-ALL.

Fungal infections pose a significant global public health threat, particularly candidemia and biofilm formation. Current antifungal drugs have limitations due to their toxicity and drug resistance. Ion interference therapy, particularly cuproptosis, shows significant potential for disease treatment. Herein, nano copper-chelate Cu(DDC)2@BSA (CDB) is synthesized for antifungal research and the mechanism of cuproptosis-like death is investigated. Initially, CDB demonstrates a strong inhibitory effect on multiple fungi and exhibits strong antifungal activity against two fluconazole-resistant clinical isolates. The decrease in ATPase activity and mitochondrial membrane potential indicates that the antifungal mechanism may involve mitochondrial dysfunction. Subsequently, transcriptome analysis reveals significant alterations in genes related to copper ions transport and regulation, oxidative phosphorylation, and mitochondrial function. Additionally, copper ions overload is observed, along with an increase in heat shock protein 70 levels and a decrease in lipoic acid synthetase protein expression. Given that biofilms hinder drug penetration, quaternary ammonium chitosan microneedles are employed in combination with CDB to penetrate the biofilm barrier and enhance the antifungal effect. Overall, this study provides new insight into the cuproptosis-like death mechanism in fungi and presents a promising strategy for fungal infection treatment through the combination of nano copper-chelate and microneedle delivery system.

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy that is commonly characterized by uncontrolled proliferation of myeloid blasts that overwhelm the bone marrow, leading to hematopoietic failure. AML is the most common form of acute leukemia in adults and its incidence increases with age. Despite recent advances, the overall prognosis of AML patients remains poor and relapse rates are high. Thus, there remains a need to identify potential therapeutic candidates that can improve patient survival outcomes and reduce the risk of relapse in AML patients. The objective of this study was to utilize transcriptomics to identify potential genes that can be targeted by drug candidates for future use in Duocarmycin SA (DSA)-targeted therapy combination studies in AML. DSA is a DNA alkylating agent that binds to the minor groove of DNA forming DNA adducts that lead to DNA damage. Previously, our lab showed that DSA reduced proliferation, induced cell cycle arrest at the G2/M phase, and triggered apoptosis in AML cells in a dose- and time-dependent manner. Therefore, we hypothesized that RNA sequencing analysis of genes obtained from DSA-treated AML cells will identify novel genes that can targeted by potential drug candidates. To test our hypothesis, human AML cell lines (Molm-14 and HL-60) were treated with high (Molm-14: 100 pM; HL-60: 500 pM) and low (Molm-14: 11.12 pM; HL-60: 112.7 pM) concentrations of DSA for 36 hours, cells were harvested, RNA was isolated and RNA sequencing and gene expression profiling analysis were performed by the Hartwell Center for Biotechnology and the Center for Applied Bioinformatics at St. Jude Children’s Research Hospital, respectively. Pathway analysis was performed using the NIH’s Database for Annotation, Visualization and Integrated Discovery (DAVID) tool to identify the top DSA-induced pathways and their associated genes. Differentially expressed genes (DEGs) for all four DSA treatment groups were identified using the cutoffs: P-value <0.05, Log2Fold Change >0.5 and <-0.5, and then the overlapping DEGs were visualized using Venny 2.1.0. Our results showed that the top pathways that were activated in all four DSA treatment groups included oxidative phosphorylation, chemical carcinogenesis - reactive oxygen species, and metabolic pathways. Genes that were upregulated within these pathways primarily included mitochondrial associated genes that play a role primarily in apoptosis (MT-ATP6, MT-CO2, and MT-ND5). Additionally, some of the pathway genes play a role in proliferation (MT-ND2 and TPM2) and chemoresistance (MT-ND2, MT-ND4 and TPM2). Our findings suggest that the genes associated with proliferation and chemoresistance can serve as potential therapeutic targets that can be used to develop novel targeted therapies to be evaluated in combination with DSA for the treatment of AML. William A. Chen, Valery Filippov, Jie Fang, Pedro Ochoa, Carlos A. Casiano, Kristopher E. Boyle, Sinisa Dovat, Hongjian Jin, Jun Yang, Olivia L. Francis-Boyle. The use of transcriptomic analysis to identify novel drug targets for DSA drug combination studies in acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2392.

Introduction Interactions between types of alterations in the IKZF1 transcription factor gene and clinical outcome in acute lymphoblastic leukemia subtypes are not fully understood. We have assessed a range of IKZF1 alterations, including focal IKZF1 deletions, the IKZF1plus genetic profile, and IKZF1 missense mutations and their associations with clinical outcome, in the context of genomic subtypes of B-acute lymphoblastic leukemia (B-ALL). Patients and Methods We analyzed single nucleotide polymorphism 6.0 microarrays, total RNA-sequencing, whole genome sequencing, and whole exome sequencing data to detect genetic alterations and subtypes in a cohort of 688 pediatric patients with B-ALL enrolled into St. Jude Total Therapy XV and XVI studies. Results IKZF1 alterations were identified in 115 (16.7%) patients, commonly in BCR::ABL1 (78%) and CRLF2-rearranged, BCR::ABL1-like B-ALL (70%) and were associated with 5-year cumulative incidence of relapse (CIR) of 14.8 ± 3.3% compared to 5.0 ± 0.9% for patients without any IKZF1 alteration (P<0.0001). IKZF1 deletions of exon 4-7 (P=0.0002), genomic IKZF1plus with any IKZF1 deletion (P=0.006) or with focal IKZF1 deletion (P=0.0007), and unfavorable genomic subtypes (P<0.005) were independently adversely prognostic. Patients with both IKZF1 exon 4-7 deletion and unfavorable genomic subtype had a significantly increased risk of relapse (HR=58.3; 95% CI, 11.9–285.4; P<0.0001), whereas IKZF1 sequence mutations were not independently predictive of outcome. Associations of genomic IKZF1plus and exon 4-7 deletions with adverse outcomes were demonstrated in an independent study group comprising 1475 patients enrolled in Children's Oncology Group clinical trials with predominantly SR B-ALL (1360 patients from AALL0331 and AALL0932 with favorable and neutral cytogenetics) or HR B-ALL (115 patients from AALL0232 and AALL1131 with favorable cytogenetics). Conclusions Genomic IKZF1plus with focal or any IKZF1 deletion, the exon 4-7 IKZF1 deletion, and unfavorable subtype are independently adversely prognostic for relapse. The combination of unfavorable genomic subtype and IKZF1 deletion of exon 4-7 identified patients at greatest risk of relapse despite MRDdirected therapy. The type of IKZF1 alteration together with subtype are informative for risk stratification and predict response in patients with B-ALL.

Increasing evidence supports the hypothesis of autologous immune attack in severe aplastic anemia(SAA):the pre-dominant role of activated cytotoxic T cells(CTL)expressing γ-interferon in inhibiting the growth of bone marrow(BM)cells,putative autoantigens,and oligoclonal expansion of CD8+T cells.1 For SAA patients,the definitive therapies are immunosuppressive therapy(IST)or he-matopoietic stem transplantation(HSCT);IST is most widely applied in the clinic because of the lack of HLA-matched sibling or unrelated donors,patients'age,and the cost of HSCT.2,3 However,only about 60％of SAA patients are responders after receiving IST,and less than 10％ach-ieve complete remission(CR)2,3;effective biomarkers for the efficacy prediction of IST in SAA patients are lacking.3 Our previous publications have demonstrated that T cell receptor(TCR)repertoire profiling has been identified as a biomarker for predicting the clinical outcomes and efficacy of patients.4,5 However,systematic evaluation of the pre-dictive value of the TCR repertoire for SAA patients during IST is still little known.