The predictive value of T-cell chimerism for disease relapse after allogeneic hematopoietic stem cell transplantation.

Introduction: Chimerism is closely correlated with disease relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, chimerism rate is dynamic changes, and the sensitivity of different chimerism requires further research. Methods: To investigate the predictive value of distinct chimerism for relapse, we measured bone marrow (BM), peripheral blood (PB), and T-cell (isolated from BM) chimerism in 178 patients after allo-HSCT. Results: Receiver operating characteristic (ROC) curve showed that T-cell chimerism was more suitable to predict relapse after allo-HSCT compared with PB and BM chimerism. The cutoff value of T-cell chimerism for predicting relapse was 99.45%. Leukemia and myelodysplastic syndrome (MDS) relapse patients' T-cell chimerism was a gradual decline from 2 months to 9 months after allo-HSCT. Higher risk of relapse and death within 1 year after allo-HSCT. The T-cell chimerism rates in remission and relapse patients were 99.43% and 94.28% at 3 months after allo-HSCT (P = 0.009), 99.31% and 95.27% at 6 months after allo-HSCT (P = 0.013), and 99.26% and 91.32% at 9 months after allo-HSCT (P = 0.024), respectively. There was a significant difference (P = 0.036) for T-cell chimerism between early relapse (relapse within 9 months after allo-HSCT) and late relapse (relapse after 9 months after allo-HSCT) at 2 months after allo-HSCT. Every 1% increase in T-cell chimerism, the hazard ratio for disease relapse was 0.967 (95% CI: 0.948-0.987, P<0.001). Discussion: We recommend constant monitoring T-cell chimerism at 2, 3, 6, and 9 months after allo-HSCT to predict relapse.

True Donor Cell Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation: Diagnostic and Therapeutic Considerations-Brief Report.

Donor cell leukemia (DCL) is a rare complication after allogeneic hematopoietic stem cell transplantation (HSCT) accounting for 0.1% of relapses and presenting as secondary leukemia of donor origin. Distinct in phenotype and cytogenetics from the original leukemia, DCL's clinical challenge lies in its late onset. Its origin is affected by donor cell anomalies, transplant environment, and additional mutations. A 43-year-old woman, treated for early stage triple-negative breast cancer, developed mixed-phenotype acute leukemia (MPAL), 12 years later. Following induction chemotherapy, myeloablative conditioning, and allo-HSCT from her fully HLA-matched brother, she exhibited multiple cutaneous relapses of the original leukemia, subsequently evolving into DCL of the bone marrow. Cytogenetic analysis revealed a complex male karyotype in 20 out of 21 metaphases, however, still showing the MPAL phenotype. DCL diagnosis was confirmed by 90.5% XY in FISH analysis and the male karyotype. Declining further intensive chemotherapy including a second allo-HSCT, she was subsequently treated with repeated radiotherapy, palliative systemic therapies, and finally venetoclax and navitoclax but died seven months post-DCL diagnosis. This case underlines DCL's complexity, characterized by unique genetics, further complicating diagnosis. It highlights the need for advanced diagnostic techniques for DCL identification and underscores the urgency for early detection and better prevention and treatment strategies.

A Case of Chronic Eosinophilic Leukemia with CSF3R-Mutant Clone and Transformed to Secondary Acute Myeloid Leukemia.

BACKGROUND: Chronic eosinophilic leukemia (CEL) is a rare invasive disease characterized by non-specific cytogenetic abnormalities or elevated mother cells, poor prognosis, and a high risk of conversion to acute leukemia. METHODS: We described the data of a patient with CEL-NOS. RESULTS: This case is a CEL-NOS with four mutations in CSF3R-T618I, DNMT3A Q816, ASXL1, and IDH2. CONCLUSIONS: The patient rapidly evolves into secondary acute myeloid leukemia (AML).

Gene expression profiling of vitamin D metabolism enzymes in leukemia and lymphoma patients: molecular aspect interplay of VDR, CYP2R1, and CYP24A1.

BACKGROUND: Vitamin D deficiency is prevalent among the Indonesian population, particularly in individuals diagnosed with leukemia-lymphoma. The regulation of vitamin D metabolism is influenced by the expression of several enzymes, such as CYP2R1, CYP24A1, and the vitamin D receptor (VDR). This study aimed to scrutinize the gene expression profiles in both mRNA and protein levels of VDR, CYP2R1, and CYP24A1 in leukemia and lymphoma patients. METHOD: The research was a cross-sectional study conducted at Cipto Mangunkusumo Hospital (RSCM) in Jakarta, Indonesia. The study included a total of 45 patients aged over 18 years old who have received a diagnosis of lymphoma or leukemia. Vitamin D status was measured by examining serum 25 (OH) D levels. The analysis of VDR, CYP2R1, and CYP24A1 mRNA expression utilized the qRT-PCR method, while protein levels were measured through the ELISA method. CONCLUSION: The study revealed a noteworthy difference in VDR protein levels between men and women. The highest mean CYP24A1 protein levels were observed in the age group > 60 years. This study found a significant, moderately positive correlation between VDR protein levels and CYP24A1 protein levels in the male and vitamin D sufficiency groups. In addition, a significant positive correlation was found between VDR mRNA levels and CYP2R1 mRNA levels, VDR mRNA levels and CYP2R1 mRNA levels, and CYP2R1 mRNA levels and CYP24A1 mRNA levels. However, the expression of these genes does not correlate with the protein levels of its mRNA translation products in blood circulation.

Music Nursing as Complementary Therapy Improves Anxiety, Fatigue, and Quality of Life in Children with Acute Leukaemia: A Retrospective Study.

OBJECTIVE: To explore the effects of music nursing as a complementary therapy on anxiety, fatigue, and quality of life in children with acute leukemia (AL). METHODS: This study included 150 children with AL admitted to our hospital from August 2021 to August 2023 and divided them into two groups based on treatment: the control (n = 76, received routine nursing) and observation (n = 74, received music nursing on the basis of routine nursing) groups. Comparison of groups was performed in terms of general information, anxiety, fatigue, and quality of life at admission (T0) and 1 month after admission (T1). RESULTS: No significant differences were observed in the general data between the two groups (P > 0.05). Anxiety, fatigue, and quality of life of the two groups also showed no significant differences at T0 (P > 0.05). The observation group showed significantly lower anxiety than the control group at T1 (P < 0.05). At T1, the observation group exhibited a lower fatigue degree compared with the control group (P < 0.05). At T1, the observation group attained higher scores on physiological and emotional dimensions of the quality of life compared with the control group, and the differences were statistically significant (P < 0.05). CONCLUSION: Music nursing for AL children, which has a certain clinical application value, can effectively reduce their anxiety and fatigue and improve their quality of life.

The graft versus leukemia effect: donor lymphocyte infusions and cellular therapy.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for many hematologic malignancies as well as non-malignant conditions. Part of the curative basis underlying HSCT for hematologic malignancies relies upon induction of the graft versus leukemia (GVL) effect in which donor immune cells recognize and eliminate residual malignant cells within the recipient, thereby maintaining remission. GVL is a clinically evident phenomenon; however, specific cell types responsible for inducing this effect and molecular mechanisms involved remain largely undefined. One of the best examples of GVL is observed after donor lymphocyte infusions (DLI), an established therapy for relapsed disease or incipient/anticipated relapse. DLI involves infusion of peripheral blood lymphocytes from the original HSCT donor into the recipient. Sustained remission can be observed in 20-80% of patients treated with DLI depending upon the underlying disease and the intrinsic burden of targeted cells. In this review, we will discuss current knowledge about mechanisms of GVL after DLI, experimental strategies for augmenting GVL by manipulation of DLI (e.g. neoantigen vaccination, specific cell type selection/depletion) and research outlook for improving DLI and cellular immunotherapies for hematologic malignancies through better molecular definition of the GVL effect.

Sequential CD7 CAR T-Cell Therapy and Allogeneic HSCT without GVHD Prophylaxis.

BACKGROUND: Patients with relapsed or refractory hematologic cancers have a poor prognosis. Chimeric antigen receptor (CAR) T-cell therapy as a bridge to allogeneic hematopoietic stem-cell transplantation (HSCT) has the potential for long-term tumor elimination. However, pre-HSCT myeloablation and graft-versus-host disease (GVHD) prophylaxis agents have toxic effects and could eradicate residual CAR T cells and compromise antitumor effects. Whether the integration of CAR T-cell therapy and allogeneic HSCT can preserve CAR T-cell function and improve tumor control is unclear. METHODS: We tested a novel "all-in-one" strategy consisting of sequential CD7 CAR T-cell therapy and haploidentical HSCT in 10 patients with relapsed or refractory CD7-positive leukemia or lymphoma. After CAR T-cell therapy led to complete remission with incomplete hematologic recovery, patients received haploidentical HSCT without pharmacologic myeloablation or GVHD prophylaxis drugs. Toxic effects and efficacy were closely monitored. RESULTS: After CAR T-cell therapy, all 10 patients had complete remission with incomplete hematologic recovery and grade 4 pancytopenia. After haploidentical HSCT, 1 patient died on day 13 of septic shock and encephalitis, 8 patients had full donor chimerism, and 1 patient had autologous hematopoiesis. Three patients had grade 2 HSCT-associated acute GVHD. The median follow-up was 15.1 months (range, 3.1 to 24.0) after CAR T-cell therapy. Six patients remained in minimal residual disease-negative complete remission, 2 had a relapse of CD7-negative leukemia, and 1 died of septic shock at 3.7 months. The estimated 1-year overall survival was 68% (95% confidence interval [CI], 43 to 100), and the estimated 1-year disease-free survival was 54% (95% CI, 29 to 100). CONCLUSIONS: Our findings suggest that sequential CD7 CAR T-cell therapy and haploidentical HSCT is safe and effective, with remission and serious but reversible adverse events. This strategy offers a feasible approach for patients with CD7-positive tumors who are ineligible for conventional allogeneic HSCT. (Funded by the National Natural Science Foundation of China and the Key Project of Science and Technology Department of Zhejiang Province; ClinicalTrials.gov numbers, NCT04599556 and NCT04538599.).

[Reversal Effect of Arctigenin on the Drug Resistance in Leukemia K562/A02 Cells and Its Mechanism].

OBJECTIVE: To study the effect of arctigenin(ARG) on adriamycin(ADM) resistance of leukemia cell line K562/A02 and the underlying mechanism. METHODS: Human leukemia cell line K562 and ADM-resistant cell line K562/A02 were cultured and treated with 2.5-50 µmol/L ADM. Cell proliferation was measured using CCK-8 method, and half maximal inhibitory concentration (IC50) was calculated. K562/A02 cells were treated with different concentrations of ARG (1, 2, 4, 8, 16 mmol/L) to detect the effect of ARG on K562/A02 cells, and a suitable concentration (2 mmol/L) was selected for subsequent experiments. K562/A02 cells were treated with 2 mmol/L ARG and 5 µmol/L ADM, and cell apoptosis was detected by flow cytometry, the expression of P-gp, MRP, cleaved caspase-3, Bax, Bcl-2 proteins and the TLR4/NF-κB signaling pathway-related proteins were measured by Western blot. TLR4 overexpression plasmid was transfected into K562/A02 cells which were co-treated with ARG and ADM, then drug sensitivity and cell apoptosis were measured. RESULTS: The IC50 value of ADM on K562/A02 cells was 36.57 µmol/L, which was significantly higher than that on K562 cells (1.30 µmol/L). ARG with a concentration of ≤2 mmol/L did not have a significant effect on K562/A02 cells. 2 mmol/L ARG significantly reduced the IC50 of ADM on K562/A02 cells. In 5 µmol/L ADM-treated K562/A02 cells, compared with the control group, the apoptosis rate of K562/A02 cells in the ARG group was significantly increased, the expressions of cleaved caspase-3, Bax proteins were significantly upregulated, the expressions of P-gp, MRP, Bcl-2, TLR4, MyD88, and p-NF-κB proteins were significantly downregulated, and the differences were statistically significant (P < 0.05). After transfection with TLR4 overexpression plasmid, the sensitivity of ARG-treated K562/A02 cells to ADM was reduced (P < 0.05), the cell apoptosis was decreased, and the expressions of P-gp, MRP, Bcl-2 and TLR4/NF-κB signaling pathway-related proteins were significantly elevated, while the expressions of cleaved caspase-3 and Bax proteins were significantly decreased (all P < 0.05). CONCLUSION: ARG may reverse the resistance of human leukemia cell line K562/A02 to ADM by inhibiting TLR4/NF-κB signaling pathway.

Deletion of the TMEM30A gene enables leukemic cell evasion of NK cell cytotoxicity.

Natural killer (NK) cell immunotherapy has gained attention as a promising strategy for treatment of various malignancies. In this study, we used a genome-wide CRISPR screen to identify genes that provide protection or susceptibility to NK cell cytotoxicity. The screen confirmed the role of several genes in NK cell regulation, such as genes involved in interferon-γ signaling and antigen presentation, as well as genes encoding the NK cell receptor ligands B7-H6 and CD58. Notably, the gene TMEM30A, encoding CDC50A-beta-subunit of the flippase shuttling phospholipids in the plasma membrane, emerged as crucial for NK cell killing. Accordingly, a broad range of TMEM30A knock-out (KO) leukemia and lymphoma cells displayed increased surface levels of phosphatidylserine (PtdSer). TMEM30A KO cells triggered less NK cell degranulation, cytokine production and displayed lower susceptibility to NK cell cytotoxicity. Blockade of PtdSer or the inhibitory receptor TIM-3, restored the NK cell ability to eliminate TMEM30A-mutated cells. The key role of the TIM-3 - PtdSer interaction for NK cell regulation was further substantiated by disruption of the receptor gene in primary NK cells, which significantly reduced the impact of elevated PtdSer in TMEM30A KO leukemic cells. Our study underscores the potential significance of agents targeting the interaction between PtdSer and TIM-3 in the realm of cancer immunotherapy.

Galectin-9, a pro-survival factor inducing immunosuppression, leukemic cell transformation and expansion.

Leukemia is a malignancy of the bone marrow and blood originating from self-renewing cancerous immature blast cells or transformed leukocytes. Despite improvements in treatments, leukemia remains still a serious disease with poor prognosis because of disease heterogeneity, drug resistance and relapse. There is emerging evidence that differentially expression of co-signaling molecules play a critical role in tumor immune evasion. Galectin-9 (Gal-9) is one of the key proteins that leukemic cells express, secrete, and use to proliferate, self-renew, and survive. It also suppresses host immune responses controlled by T and NK cells, enabling leukemic cells to evade immune surveillance. The present review provides the molecular mechanisms of Gal-9-induced immune evasion in leukemia. Understanding the complex immune evasion machinery driven by Gal-9 expressing leukemic cells will enable the identification of novel therapeutic strategies for efficient immunotherapy in leukemic patients. Combined treatment approaches targeting T-cell immunoglobulin and mucin domain-3 (Tim-3)/Gal-9 and other immune checkpoint pathways can be considered, which may enhance the efficacy of host effector cells to attack leukemic cells.

Cas9-directed long-read sequencing to resolve optical genome mapping findings in leukemia diagnostics.

Leukemias are genetically heterogeneous and diagnostics therefore includes various standard-of-care (SOC) techniques, including karyotyping, SNP-array and FISH. Optical genome mapping (OGM) may replace these as it detects different types of structural aberrations simultaneously and additionally detects much smaller aberrations (500 bp vs 5-10 Mb with karyotyping). However, its resolution may still be too low to define clinical relevance of aberrations when they are located between two OGM labels or when labels are not distinct enough. Here, we test the potential of Cas9-directed long-read sequencing (LRS) as an additional technique to resolve such potentially relevant new findings. From an internal Bionano implementation study we selected ten OGM calls that could not be validated with SOC methods. Per variant we designed crRNAs for Cas9 enrichment, prepared libraries and sequenced them on a MinION/GridION device. We could confirm all aberrations and, importantly, the actual breakpoints of the OGM calls were located between 0.2 and 5.5 kb of the OGM-estimated breakpoints, confirming the high reliability of OGM. Furthermore, we show examples of redefinition of aberrations between labels that enable judgment of clinical relevance. Our results suggest that Cas9-directed LRS can be a relevant and flexible secondary technique in diagnostic workflows including OGM.

A rare KMT2A::CBL transcript in an acute monoblastic leukemia patient with an unfavorable outcome.

BACKGROUND: Lysine [K] methyltransferase 2A (KMT2A, previously known as MLL) gene rearrangements are common in acute leukemias of various lineages and are associated with features such as chemotherapy resistance and rapid relapse. KMT2A::CBL is a rare fusion of unknown pathogenesis generated by a unique interstitial deletion of chromosome 11 that has been reported across a wide age range in both acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) patients. The leukemogenic effect of the KMT2A::CBL rearrangement and its association with clinical prognosis have not been well clarified. METHODS AND RESULTS: We report the case of a 64-year-old female who was diagnosed with acute monoblastic leukemia (M5a) and who acquired the rare KMT2A::CBL fusion. The patient received multiple cycles of therapy but did not achieve remission and eventually succumbed to severe infection and disease progression. Additionally, we characterized the predicted KMT2A-CBL protein structure in this case to reveal the underlying leukemogenic mechanisms and summarized reported cases of hematological malignancies with KMT2A::CBL fusion to investigate the correlation of gene rearrangements with clinical outcomes. CONCLUSIONS: This report provides novel insights into the leukemogenic potential of the KMT2A::CBL rearrangement and the correlation between gene rearrangements and clinical outcomes.

Cancer statistics in Yemen: incidence and mortality, in 2020.

BACKGROUND: The current cancer epidemiological profile in Yemen suffers from a lack of locally representative data and resources, posing a challenge in determining the real incidence, prevalence, survival and mortality rates, particularly data extracted from national hospitals. This study aims to provide a comprehensive overview of the cancer burden and trends in Yemen for 2020, including incidence and mortality rates. METHODS: The current study provides cancer statistics and their trends in Yemen, including incidence and mortality, in 2020 by using descriptive statistics. The data was obtained using the Global Cancer Observatory (GCO) 2020 online database. RESULTS: According to the (GCP) database in 2020, the crude incidence rate (CIR) of all cancers in Yemen was 55.2 per 100.000. The age-standardized rate (ASR) was 97.0 per 100.000, and the cumulative risk (0-74) was 22.0 per 100.000. The age-standardized rate (ASR) was 76.5 per 100.000, and the cumulative risk (0-74) was 19.6 per 100.000. Furthermore, the crude mortality rate (CIR) of all cancers was 40.6 per 100.000. Breast cancer was most prevalent in Yemen across all age groups and genders (31.1%), followed by colorectal cancer (7.7%) and leukemia (5.7%). Breast cancer also ranked as the primary cause of mortality at an estimated percentage of 13.5%, followed by colorectal cancer (8.8%) and stomach cancer (7.1%). CONCLUSION: Cancer has become a significant life-threatening illness in Yemen with an increase in the disease burden of breast cancer in women. Furthermore, leukemia in children and colorectal cancer in both sexes have experienced a more significant burden as well. Therefore, it is imperative for initiatives for cancer control and prevention to be prioritised at national and regional levels.

Single-cell systems pharmacology identifies development-driven drug response and combination therapy in B cell acute lymphoblastic leukemia.

Leukemia can arise at various stages of the hematopoietic differentiation hierarchy, but the impact of developmental arrest on drug sensitivity is unclear. Applying network-based analyses to single-cell transcriptomes of human B cells, we define genome-wide signaling circuitry for each B cell differentiation stage. Using this reference, we comprehensively map the developmental states of B cell acute lymphoblastic leukemia (B-ALL), revealing its strong correlation with sensitivity to asparaginase, a commonly used chemotherapeutic agent. Single-cell multi-omics analyses of primary B-ALL blasts reveal marked intra-leukemia heterogeneity in asparaginase response: resistance is linked to pre-pro-B-like cells, with sensitivity associated with the pro-B-like population. By targeting BCL2, a driver within the pre-pro-B-like cell signaling network, we find that venetoclax significantly potentiates asparaginase efficacy in vitro and in vivo. These findings demonstrate a single-cell systems pharmacology framework to predict effective combination therapies based on intra-leukemia heterogeneity in developmental state, with potentially broad applications beyond B-ALL.

Targeting ferroptosis for leukemia therapy: exploring novel strategies from its mechanisms and role in leukemia based on nanotechnology.

The latest findings in iron metabolism and the newly uncovered process of ferroptosis have paved the way for new potential strategies in anti-leukemia treatments. In the current project, we reviewed and summarized the current role of nanomedicine in the treatment and diagnosis of leukemia through a comparison made between traditional approaches applied in the treatment and diagnosis of leukemia via the existing investigations about the ferroptosis molecular mechanisms involved in various anti-tumor treatments. The application of nanotechnology and other novel technologies may provide a new direction in ferroptosis-driven leukemia therapies. The article explores the potential of targeting ferroptosis, a new form of regulated cell death, as a new therapeutic strategy for leukemia. It discusses the mechanisms of ferroptosis and its role in leukemia and how nanotechnology can enhance the delivery and efficacy of ferroptosis-inducing agents. The article not only highlights the promise of ferroptosis-targeted therapies and nanotechnology in revolutionizing leukemia treatment, but also calls for further research to overcome challenges and fully realize the clinical potential of this innovative approach. Finally, it discusses the challenges and opportunities in clinical applications of ferroptosis.

Targeted therapies for HPV-associated cervical cancer: Harnessing the potential of exosome-based chipsets in combating leukemia and HPV-mediated cervical cancer.

Exosomes play a crucial role in intercellular communication and have emerged as significant vehicles for transporting disease-specific biomarkers. This feature provides profound insights into the progression of diseases and the responses of patients to treatments. For example, in leukemia, exosomes convey critical information through the carriage of specific proteins and nucleic acids. In the case of human papillomavirus (HPV)-mediated cervical cancer, exosomes are particularly useful for noninvasive detection as they transport high-risk HPV DNA and specific biomolecules, which can be indicators of the disease. Despite their vast potential, there are several challenges associated with the use of exosomes in medical diagnostics. These include their inherent heterogeneity, the need for enhanced sensitivity in detection methods, the establishment of standardization protocols, and the requirement for cost-effective scalability in their application. Addressing these challenges is crucial for the effective implementation of exosome-based diagnostics. Future research and development are geared towards overcoming these obstacles. Efforts are concentrated on refining the processes of biomarker discovery, establishing comprehensive regulatory frameworks, developing convenient point-of-care devices, exploring methods for multimodal detection, and conducting extensive clinical trials. The ultimate goal of these efforts is to inaugurate a new era of precision diagnostics within healthcare. This would significantly improve patient outcomes and reduce the burden of diseases such as leukemia and HPV-mediated cervical cancer. The integration of exosomes with cutting-edge technology holds the promise of significantly reinforcing the foundations of healthcare, leading to enhanced diagnostic accuracy, better disease monitoring, and more personalized therapeutic approaches.

Evaluating the safety and efficacy of cryopreserved ovarian tissue transplantation in leukemia patients with different bone marrow remission status using xenotransplantation.

Background: Leukemia patients undergoing cryopreserved ovarian tissue transplantation (OTT) may carry a high risk of disease induction. Measurable residual disease (MRD) in bone marrow is linked to an elevated risk of relapse. It is controversial whether leukemia patients must be allowed to achieve measurable residual disease negative (MRD-negative) status instead of measurable residual disease positive (MRD-positive) status before ovarian tissue cryopreservation (OTC). Objective: To explore the safety and efficacy of OTT in acute leukemia patients with different MRD status by using xenotransplantation. Method: Cryopreserved ovarian tissue from 19 leukemia patients was thawed and xenotransplanted to ovariectomized BALB/C nude mice (n=36). The mice were divided into 2 groups based on the patient's MRD status before OTC: MRD-negative group (n=18) and MRD-positive group (n=18), additionally, a control group consisted of ovariectomized mice (n=9). Body weight was measured weekly and mortality, emaciation, and other abnormalities were recorded. Twenty-six weeks post-surgery, livers, spleens, uteruses, and ovarian grafts were removed for macroscopic and histological examinations to evaluate the efficacy of xenotransplantation and assess malignant cell contamination in mice. Results: Follicle growth was visible in the ovarian grafts of the MRD-negative and MRD-positive groups. Compared with the ovariectomized group, a significant decrease in body weight (p<0.01) was noted, the uterine volume was notably larger, estradiol (E2) levels were significantly higher (p<0.01), and follicle-stimulating hormone (FSH) levels were significantly lower (p<0.001) in the other two groups. Mice in the MRD-positive group showed a significantly higher incidence of death (p<0.001) and emaciation (p<0.01), compared to the MRD-negative group. Histological observation revealed the presence of malignant cells in the grafts, livers, and spleens of 3 mice in the MRD-positive group. No abnormalities were observed in the mice from the MRD-negative group in both macroscopic and histological observations except one mouse was sacrificed for ascites unrelated to leukemia relapse. Conclusion: For leukemia patients having ovarian tissue preserved in the first and only centralized human ovarian tissue cryobank in China, immunodeficient mice xenotransplantation can be a method to evaluate the safety and efficacy of OTT; the risk of malignant cell reimplantation due to OTT is higher in leukemia patients with MRD-positive status than those with MRD-negative status before OTC.

The role of immune reconstitution in relapse after allogeneic hematopoietic stem cell transplantation.

INTRODUCTION: Leukemia relapse following stem cell transplantation remains a significant barrier to long-term remission. Timely and balanced immune recovery after transplantation is crucial for preventing leukemia relapse. AREAS COVERED: After an extensive literature search of PubMed and Web of Science through October 2023, we provide an overview of the dynamics of immune reconstitution and its role in controlling leukemia relapse. We also discuss strategies to promote immune reconstitution and reduce disease recurrence following allogeneic hematopoietic stem cell transplantation. EXPERT OPINION: Immune reconstitution after transplantation has substantial potential to prevent relapse and might predict disease recurrence and prognosis. High dimensional cytometry, multi-omics, and T cell repertoire analysis allow for a more comprehensive and detailed understanding of the immune system's dynamics post-transplantation, and contribute to the identification of rare immune cell subsets or potential biomarkers associated with successful immune reconstitution or increased risk of complications. Strategies to enhance the immune system, such as adoptive immunotherapy and cytokine-based therapy, have great potential for reducing leukemia relapse after transplantation. Future research directions should focus on refining patient selection for these therapies, implementing appropriate and timely treatment, investigating combination approaches to maximize therapeutic outcomes, and achieving a robust graft-versus-leukemia (GVL) effect while minimizing graft-versus-host disease (GVHD) for optimal results.