Nomogram establishment for short-term survival prediction in ICU patients with aplastic anemia based on the MIMIC-IV database.

OBJECTIVE: To establish an efficient nomogram model to predict short-term survival in ICU patients with aplastic anemia (AA). METHODS: The data of AA patients in the MIMIC-IV database were obtained and randomly assigned to the training set and testing set in a ratio of 7:3. Independent prognosis factors were identified through univariate and multivariate Cox regression analyses. The variance inflation factor was calculated to detect the correlation between variables. A nomogram model was built based on independent prognostic factors and risk scores for factors were generated. Model performance was tested using C-index, receiver operating characteristic (ROC) curve, calibration curve, decision curve analysis (DCA) and Kaplan-Meier curve. RESULTS: A total of 1,963 AA patients were included. A nomogram model with 7 variables was built, including SAPS II, chronic pulmonary obstructive disease, body temperature, red cell distribution width, saturation of peripheral oxygen, age and mechanical ventilation. The C-indexes in the training set and testing set were 0.642 and 0.643 respectively, indicating certain accuracy of the model. ROC curve showed favorable classification performance of nomogram. The calibration curve reflected that its probabilistic prediction was reliable. DCA revealed good clinical practicability of the model. Moreover, the Kaplan-Meier curve showed that receiving mechanical ventilation could improve the survival status of AA patients in the short term but did not in the later period. CONCLUSION: The nomogram model of the short-term survival rate of AA patients was built based on clinical characteristics, and early mechanical ventilation could help improve the short-term survival rate of patients.

Quality of life after immune suppressive therapy in aplastic anemia.

Acquired aplastic anemia (AA) is a rare form of immune-mediated bone marrow failure, which can result in life-threatening infections or bleeding if left untreated. Treatment consists of either immune suppressive therapy (IST) or allogeneic stem cell transplantation (alloHSCT). While considerable research has been published regarding survival, response rate and toxicity of both treatments, knowledge on the impact on quality of life (QoL) is scarce. We used the recently developed AA-specific QoL questionnaire (QLQ-AA/PNH-54) to evaluate QoL in a single center cohort of AA patients who were successfully treated with IST. The 54 questions represent 12 different QoL domains. Results were analyzed for all patients and grouped based on hematologic response (complete response (CR) or partial response (PR)). Thirty-six successfully treated adult patients (15 in CR, 21 in PR) completed the questionnaire (median age 54 years, range 21-71; median time since last IST 5 years, range 0-41). Fatigue was experienced by 83% of patients. Even though total QoL scores did not significantly differ between patients with PR and CR (105 vs 92, p-value 0,17) there appeared to be a trend towards higher scores in patients with PR, especially in domains concerning psychological wellbeing. This trend was most clear in the domains fear of progression (2,12 in PR patients vs 1,73 in CR patients; p-value 0,08) and role functioning (2,22 vs 1,88; p-value 0,07). In conclusion, patients with AA continue to experience psychological and physical effects despite successful IST.

Donor-type bone marrow aplasia following hematopoietic stem cell transplantation in a child with a novel SAMD9L variant.

Pathogenic variants in the genes SAMD9 (sterile a-motif domain containing protein - 9) and SAMD9L (SAMD9-like) cause bone marrow failure with characteristic syndromic features. We report a case of a previously healthy, 3-year-old boy with no dysmorphology, who presented with severe aplastic anemia and a novel variant in the SAMD9L gene. His father, elder brother and sister who harbored the same variant were completely healthy. In the absence of a matched unrelated donor, he underwent a stem cell transplant from his sister, a 10/10 match. Almost 2 years later he developed donor type aplasia and succumbed to an invasive fungal infection after a failed haplograft from his mother. This case highlights the pathogenicity of this previously undescribed germline variation of uncertain significance in the SAMD9L gene and the value of comprehensive genetic testing for inherited bone marrow failures even in the absence of a positive family history or characteristic congenital abnormalities.

Bone marrow CD8+ Trm cells induced by IL-15 and CD16+ monocytes contribute to HSPC destruction in human severe aplastic anemia.

Idiopathic severe aplastic anemia (SAA) is a disease of bone marrow failure caused by T-cell-induced destruction of hematopoietic stem and progenitor cells (HSPCs), however the mechanism remains unclear. We performed single-cell RNA sequencing of PBMCs and BMMCs from SAA patients and healthy donors and identified a CD8+ T cell subset with a tissue residency phenotype (Trm) in bone marrow that exhibit high IFN-γ and FasL expression and have a higher ability to induce apoptosis in HSPCs in vitro through FasL expression. CD8+ Trm cells were induced by IL-15 presented by IL-15Rα on monocytes, especially CD16+ monocytes, which were increased in SAA patients. CD16+ monocytes contributed to IL-15-induced CD38+CXCR6+ pre-Trm differentiation into CD8+ Trm cells, which can be inhibited by the CD38 inhibitor 78c. Our results demonstrate that IL-15-induced CD8+ Trm cells are pathogenic cells that mediate HSPC destruction in SAA patients and are therapeutic targets for future treatments.

Mendelian randomization of circulating proteome identifies IFN-γ as a druggable target in aplastic anemia.

BACKGROUND: Aplastic anemia (AA) is a kind of bone marrow failure (BMF) characterized by pancytopenia with hypoplasia/aplasia of bone marrow. Immunosuppressive therapy and bone marrow transplantation are effective methods to treat severe aplastic anemia. However, the efficacy is limited by complications and the availability of suitable donors. This study aimed to determine whether any circulating druggable protein levels may have causal effects on AA and provide potential novel drug targets for AA. METHODS: Genetic variants strongly associated with circulating druggable protein levels to perform Mendelian randomization (MR) analyses were used. The effect of these druggable protein levels on AA risk was measured using the summary statistics from a large-scale proteomic genome-wide association study (GWAS) and FinnGen database ( https://www.finngen.fi/en/access_results ). Multivariable MR analyses were performed to statistically adjust for potential confounders, including platelet counts, reticulocyte counts, neutrophil counts, and proportions of hematopoietic stem cells. RESULTS: The data showed that higher level of circulating IFN-γ levels was causally associated with AA susceptibility. The causal effects of circulating IFN-γ levels on the AA were broadly consistent, when adjusted for platelet counts, reticulocyte counts, neutrophil counts and proportions of hematopoietic stem cells. CONCLUSIONS: High levels of circulating IFN-γ levels might increase the risk of AA and might provide a potential novel target for AA.

The state of the art in the treatment of severe aplastic anemia: immunotherapy and hematopoietic cell transplantation in children and adults.

Acquired aplastic anemia (AA) is an immune-mediated bone marrow (BM) failure where marrow disruption is driven by a cytotoxic T-cell-mediated autoimmune attack against hematopoietic stem cells. The key diagnostic challenge in children, but also in adults, is to exclude the possible underlying congenital condition and myelodysplasia. The choice of treatment options, either allogeneic hematopoietic cell transplantation (alloHCT) or immunosuppressive therapy (IST), depends on the patient's age, comorbidities, and access to a suitable donor and effective therapeutic agents. Since 2022, horse antithymocyte globulin (hATG) has been available again in Europe and is recommended for IST as a more effective option than rabbit ATG. Therefore, an update on immunosuppressive strategies is warranted. Despite an improved response to the new immunosuppression protocols with hATG and eltrombopag, some patients are not cured or remain at risk of aplasia relapse or clonal evolution and require postponed alloHCT. The transplantation field has evolved, becoming safer and more accessible. Upfront alloHCT from unrelated donors is becoming a tempting option. With the use of posttransplant cyclophosphamide, haploidentical HCT offers promising outcomes also in AA. In this paper, we present the state of the art in the management of severe AA for pediatric and adult patients based on the available guidelines and recently published studies.

Comparable outcomes with low-dose and standard-dose horse anti-thymocyte globulin in the treatment of severe aplastic anemia.

BACKGROUND: The standard dose (SD) of horse anti-thymocyte globulin (hATG) ATGAM (Pfizer, USA) or its biosimilar thymogam (Bharat Serum, India) for the treatment of Aplastic Anemia (AA) is 40 mg/kg/day for 4 days in combination with cyclosporine. Data on the impact of hATG dose on long-term outcomes are limited. Here, we describe our comparative experience using 25 mg/kg/day (low-dose [LD]) hATG for 4 days with SD for the treatment of AA. METHODS: We retrospectively studied patients with AA (age > 12 years) who received two doses of hATG combined with cyclosporine. Among 93 AA patients who received hATG, 62 (66.7%) and 31 (33.3%) patients received LD and SD hATG with cyclosporine, respectively. Among these,seventeen(18.2%) patients also received eltrombopag with hATG and cyclosporine. Overall response rates [complete response (CR) and partial response (PR)] of LD and SD hATG groups at 3 months (50% vs. 48.4%; p = 0.88), 6 months (63.8% vs. 71.4%; p = 0.67), and 12 months (69.6% vs. 79.2%; p = 0.167) were comparable. The mean (Standard Deviation) 5-year Kaplan-Meier estimate of overall survival and event-free survival was 82.1 (4.6)% and 70.9 (5.5)% for the study population. The mean (standard deviation) 5-year Kaplan-Meier estimate of overall survival and event-free survival of those who received LD hATG versus SD hATG dose was 82.9 (5·3)% versus 74.8 (10·3)% (P = 0·439), and 75.2 (6.2)% versus 61.4(11.2)% (P = 0·441). CONCLUSION: Our study revealed that the response rates of patients with AA and LD were similar to those of patients with SD to hATG combined with cyclosporine in a real-world setting.

[Single non-blood-related umbilical cord blood transplantation using a reduced-intensity conditioning regimen for the treatment of severe aplastic anemia].

Objective: To evaluated the clinical efficacy of a reduced-intensity preconditioning regimen for single non-blood-related umbilical cord blood transplantation (sUCBT) in the treatment of severe aplastic anemia (SAA) . Methods: The clinical data of 63 patients with SAA who underwent sUCBT from January 2021 to July 2023 at the Department of Hematology of the First Affiliated Hospital of USTC were retrospectively analyzed. Fifty-two patients received total body irradiation/total bone marrow irradiation (TMI) combined with fludarabine or a cyclophosphamide- conditioning regimen (non-rATG group) , while 11 patients received rabbit anti-human thymocyte immunoglobulin (rATG) combined with TMI, fludarabine, or the cyclophosphamide-conditioning regimen (rATG group) . All patients received cyclosporine A and mycophenolate mofetil for graft-versus-host disease (GVHD) prophylaxis. Complications post-transplantation and long-term survival were compared between the two groups. Results: The baseline parameters were balanced between the two groups (P>0.05) . In the rATG group, all patients achieved stem cell engraftment, and in the non-rATG group, five patients had primary graft failure. There was no significant difference in the cumulative incidence of neutrophil engraftment at 42 days after transplantation or platelet engraftment at 60 days between the two groups. The incidence of grade Ⅱ-Ⅳ acute GVHD in the rATG group was significantly lower than in the non-rATG group (10.0% vs. 46.2% , P=0.032) , and the differences in the cumulative incidences of grade Ⅲ/Ⅳ acute GVHD and 1-year chronic GVHD were not statistically significant (P=0.367 and P=0.053, respectively) . There were no significant differences in the incidences of pre-engraftment syndrome, bacterial bloodstream infections, cytomegalovirus viremia, or hemorrhagic cystitis between the two groups (P>0.05 for all) . The median follow-up time for surviving patients was 536 (61-993) days, and the 1-year transplantation related mortality (TRM) of all patients after transplantation was 13.0% (95% CI 6.7% -24.3% ) . Among the patients in the non-rATG and rATG groups, 15.5% (95% CI 8.1% -28.6% ) and 0% (P=0.189) , respectively, had mutations. The 1-year overall survival (OS) rate of all patients after transplantation was 87.0% (95% CI 75.7% -93.3% ) . The 1-year OS rates in the rATG group and non-rATG group after transplantation were 100% and 84.5% , respectively (95% CI 71.4% -91.9% ) (P=0.198) . Conclusion: The preliminary results of sUCBT with a low-dose irradiation-based reduced-intensity conditioning regimen with fludarabine/cyclophosphamide for the treatment of patients with SAA showed good efficacy. Early application of low-dose rATG can reduce the incidence of acute GVHD after transplantation without increasing the risk of implantation failure or infection.

Safety and efficacy of eltrombopag in patients with aplastic anemia: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: This article conducts a systematic review of eltrombopag combined with immunosuppressive therapy for the treatment of aplastic anemia (AA), to demonstrate the effectiveness and safety of eltrombopag. METHODS: PubMed, Cochrane Library, Embase, OVID, Web of Science, China National Knowledge Infrastructure, and Wanfang databases were searched. Studies that met the inclusion criteria were collected, ranging from the establishment of the database to August 2023. Two reviewers performed meta-analyses using the Cochrane systematic review method and RevMan 5.3 software. RESULTS: This meta-analysis enrolled 5 studies with a total of 542 AA patients, including 274 in the experimental group and 268 in the control group. Meta-analyses were performed for efficacy and adverse reactions. The endpoint of effects included 6-month complete response (CR), 6-month partial response (PR), and 6-month overall response (OR). Eltrombopag combined with immunotherapy showed significant improvements in 6-month CR (OR: 2.20; 95% CI;1.54-3.12; P < 0.0001) and 6-month OR (OR = 3.66, 95% CI 2.39-5.61, P < 0.001)compared to immunosuppressive therapy for AA patients. In terms of safety, eltrombopag combined with immunosuppressive therapy showed significantly increased pigment deposition and abnormal liver function compared to immunosuppressive therapy alone. CONCLUSION: Compared to immunosuppressive therapy alone, eltrombopag combined with immunosuppressive therapy showed significant improvements in 6-month CR and 6-month OR. However, it also resulted in increased pigment deposition and abnormal liver function in terms of safety.

Pancytopenia with aplastic anemia in systemic lupus erythematosus: case series and literature review.

Aplastic anemia (AA) is a rare, potentially catastrophic hematopoiesis failure manifested by pancytopenia and bone marrow aplasia. AA occurrence in Systemic Lupus Erythematosus (SLE) patients is extremely rare. The diagnosis may be delayed due to other possible pancytopenia etiologies. Confirmation of peripheral cytopenias diagnosis necessitates a bone marrow aspiration. The management of AA is challenging, and the literature reported using glucocorticoids, danazol, plasmapheresis, cyclophosphamide, intravenous immunoglobulin, and cyclosporine. We report two cases of SLE patients who presented with pancytopenia, with bone marrow biopsy confirmed AA. One case was treated with cyclophosphamide but unfortunately succumbed to Acute Respiratory Distress Syndrome (ARDS), while the other case was managed with rituximab with a good response. Interestingly, both patients were on azathioprine before the diagnosis of AA. A comprehensive search for reported cases of AA in PubMed, Scopus, and the Directory of Open Access Journals databases was performed to enhance the understanding of the diagnostic and management challenges associated with AA in SLE, facilitating ongoing exploration and research in this field. The decision to do a BM aspiration and biopsy is recommended for SLE patients with an abrupt decline in blood counts and previously stable blood counts.

Efficacy, Safety, and Population Pharmacokinetics of Eltrombopag in Children with Different Severities of Aplastic Anemia.

Eltrombopag was approved as a first-line treatment for patients older than 2 years old with severe aplastic anemia (SAA). However, data on eltrombopag in children with different types of aplastic anemia (AA), especially non-severe AA (NSAA), are limited. We performed a prospective, single-arm, and observational study to investigate eltrombopag's efficacy, safety, and pharmacokinetics in children with NSAA, SAA, and very severe AA (VSAA). The efficacy and safety were assessed every 3 months. The population pharmacokinetic (PPK) model was used to depict the pharmacokinetic profile of eltrombopag. Twenty-three AA children with an average age of 7.9 (range of 3.0-14.0) years were enrolled. The response (complete and partial response) rate was 12.5%, 50.0%, and 100.0% after 3, 6, and 12 months in patients with NSAA. For patients with SAA and VSAA, these response rates were 46.7%, 61.5%, and 87.5%. Hepatotoxicity occurred in one patient. Fifty-three blood samples were used to build the PPK model. Body weight was the only covariate for apparent clearance (CL/F) and volume of distribution. The allele-T carrier of adenosine triphosphate-binding cassette transporter G2 was found to increase eltrombopag's clearance. However, when normalized by weight, the clearance between the wild-type and variant showed no statistical difference. In patients with response, children with NSAA exhibited lower area under the curve from time zero to infinity, higher CL/F, and higher weight-adjusted CL/F than those with SAA or VSAA. However, the differences were not statistically significant. The results may support further individualized treatment of eltrombopag in children with AA.

When inflammatory stressors dramatically change, disease phenotypes may transform between autoimmune hematopoietic failure and myeloid neoplasms.

Aplastic anemia (AA) and hypoplastic myelodysplastic syndrome are paradigms of autoimmune hematopoietic failure (AHF). Myelodysplastic syndrome and acute myeloid leukemia are unequivocal myeloid neoplasms (MNs). Currently, AA is also known to be a clonal hematological disease. Genetic aberrations typically observed in MNs are detected in approximately one-third of AA patients. In AA patients harboring MN-related genetic aberrations, a poor response to immunosuppressive therapy (IST) and an increased risk of transformation to MNs occurring either naturally or after IST are predicted. Approximately 10%-15% of patients with severe AA transform the disease phenotype to MNs following IST, and in some patients, leukemic transformation emerges during or shortly after IST. Phenotypic transformations between AHF and MNs can occur reciprocally. A fraction of advanced MN patients experience an aplastic crisis during which leukemic blasts are repressed. The switch that shapes the disease phenotype is a change in the strength of extramedullary inflammation. Both AHF and MNs have an immune-active bone marrow (BM) environment (BME). In AHF patients, an inflamed BME can be evoked by infiltrated immune cells targeting neoplastic molecules, which contributes to the BM-specific autoimmune impairment. Autoimmune responses in AHF may represent an antileukemic mechanism, and inflammatory stressors strengthen antileukemic immunity, at least in a significant proportion of patients who have MN-related genetic aberrations. During active inflammatory episodes, normal and leukemic hematopoieses are suppressed, which leads to the occurrence of aplastic cytopenia and leukemic cell regression. The successful treatment of underlying infections mitigates inflammatory stress-related antileukemic activities and promotes the penetration of leukemic hematopoiesis. The effect of IST is similar to that of treating underlying infections. Investigating inflammatory stress-powered antileukemic immunity is highly important in theoretical studies and clinical practice, especially given the wide application of immune-activating agents and immune checkpoint inhibitors in the treatment of hematological neoplasms.

Insufficient phosphorylation of STAT5 in Tregs inhibits the expression of BLIMP-1 but not IRF4, reduction the proportion of Tregs in pediatric aplastic anemia.

Deficiency in regulatory T cells (Tregs) is an important mechanism underlying the pathogenesis of pediatric aplastic anemia, but its specific mechanism is unclear. In our study, we aimed to investigate whether IL-2/STAT5 can regulate the proliferation of Tregs in aplastic anemia (AA) by regulating their expression of B lymphocyte-induced mature protein-1 (BLIMP-1) or interferon regulatory factor 4 (IRF4). Through clinical research and animal experiments, we found that poor activation of the IL-2/STAT5 signaling pathway may leads to low expression of BLIMP-1 in Tregs of children with AA, which leads to defects in the differentiation and proliferation of Tregs in AA. In AA model mice, treatment with IL-2c reversed the decrease in Treg proportions and reduction in Blimp-1 expression in Tregs by increasing the phosphorylation of Stat5 in Tregs. In AA, deficiency of IRF4 expression in Tregs is closely related to the deficiency of Tregs, but is not regulated by the IL-2/STAT5 pathway.

Dioscin alleviates aplastic anemia through regulatory T cells promotion.

Objectives: Aplastic anemia (AA) is one of the immune-mediated bone marrow failure disorders caused by multiple factors, including the inability of CD4 + CD25 + regulatory T cells (Tregs) to negatively regulate cytotoxic T lymphocytes (CTLs). Dioscin is a natural steroid saponin that has a similar structure to steroid hormones. The purpose of this study is to look into the effect of Dioscin on the functions of CD4 + CD25+ Tregs in the AA mouse model and explore its underlying mechanism.Methods: To begin with, bone marrow failure was induced through total body irradiation and allogeneic lymphocyte infusion using male Balb/c mice. After 14 consecutive days of Dioscin orally administrated, the AA mouse model was tested for complete blood counts, HE Staining of the femur, Foxp3, IL-10 and TGF-ß. Then CD4 + CD25+ Tregs were isolated from splenic lymphocytes of the AA mouse model, Tregs and the biomarkers and cytokines of Tregs were measured after 24 h of Dioscin intervention treatment in vitro.Results: Dioscin promotes the expression of Foxp3, IL-10, IL-35 and TGF-ß, indicating its Tregs-promoting properties. Mechanistically, the administration of Dioscin resulted in the alteration of CD152, CD357, Perforin and CD73 on the surface of Tregs, and restored the expression of Foxp3.Conclusion: Dioscin markedly attenuated bone marrow failure, and promoted Tregs differentiation, suggesting the maintenance of theimmune balance effect of Dioscin. Dioscin attenuates pancytopenia and bone marrow failure via its Tregs promotion properties.

Recombinant Human Thrombopoietin Promotes Platelet Engraftment in Severe Aplastic Anemia Patients Following Treatment With Haploid Hematopoietic Stem Cell Transplantation using Modified Post-Transplantation Cyclophosphamide.

BACKGROUND: Recombinant human TPO (rhTPO) promotes platelet engraftment in patients after allogeneic HSCT (allo-HSCT). However, the effects of rhTPO on platelet recovery after Haplo-HSCT in patients with severe aplastic anemia (SAA) have not been intensively studied. OBJECTIVE: We aimed to evaluate the efficacy of rhTPO on platelet engraftment in patients with SAA who were treated with Haplo-HSCT using post-transplantation cyclophosphamide (PTCy). STUDY DESIGN: SAA patients who received Haplo-HSCT plus PTCy regimen were divided into the rhTPO group (with subcutaneous injection of rhTPO, n = 28) and Control group (no rhTPO administration, n = 27). The engraftment of platelet/neutrophil, platelet infusion amount, and transplant-related complications between the 2 groups were compared. RESULTS: All 55 patients showed successful hematopoietic reconstitution. The median time of platelet engraftment was 11 (9 to 29) days in the rhTPO group and 14 (9 to 28) days in the Control group (P = .003). The rhTPO group had a significantly reduced amount of infused platelets compared to the Control group (2 (1 to 11.5) versus 3 (1 to 14) therapeutic doses; P = .004). There was no significant difference between the 2 groups regarding median time of neutrophil engraftment, incidence of acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD), incidence of cytomegalovirus or Epstein-Barr virus reactivation, 3-yr overall survival rate, and failure-free-survival rate. No obvious adverse reactions were observed in the rhTPO group. CONCLUSION: rhTPO promoted platelet engraftment, reduced the amount of transfused platelets, and demonstrated good safety profiles without evidence of adverse reactions in patients with SAA who received Haplo-HSCT using PTCy regimen.

Formononetin reverses Treg/Th17 imbalance in immune-mediated bone marrow failure mice by regulating the PI3K/Akt signaling pathway.

BACKGROUND: Severe aplastic anemia (SAA) is a syndrome of bone marrow failure which is life-threatening. Recent studies have demonstrated that CD4 + T cell subsets, including T regulatory (Treg) and T helper 17 (Th17) cells, play a pivotal role in the pathogenesis of SAA. Formononetin (FMN) is a natural compound extracted from the traditional Chinese medicine Huangqi, which has the ability to regulate the imbalance of Treg/Th17 cells in some inflammatory diseases. Nevertheless, the therapeutic effect of FMN in SAA has yet to be definitively established. Therefore, the objective of this research was to investigate the effect of FMN on SAA and elucidate its underlying mechanism. METHODS: In vivo experiments, the mice were divided into the following five groups: control, model, low-dose FMN, high-dose FMN, and positive control cyclosporine A group. The immune-mediated bone marrow failure (BMF) mouse model was established by the total body X-ray radiation and lymphocyte infusion. After 10 days of continuous administration of FMN, the numbers of Treg/Th17 cells in the bone marrow and spleen were assessed by flow cytometry. The protein expressions of PI3K/Akt pathway in the bone marrow and spleen was assessed by immunohistochemistry and western blotting. In vitro, the impact of FMN on the differentiation of naive CD4 + T cells into Treg cells was investigated by flow cytometry and ELISA. RESULTS: In comparison with the control group, the model group showed a reduction in bone marrow nucleated cells, a significant decrease in peripheral blood cells, and an altered CD8 + /CD4 + T cell ratio. These findings indicate the successful establishment of a mouse model of immune-mediated BMF. After FMN treatment, there were the increased levels of red blood cells and hemoglobin. In addition, FMN mitigated the bone marrow destruction and restored the CD8 + /CD4 + T cell ratio. Furthermore, in comparison with the control group, the model group showed the decreased levels of Treg cells and the increased levels of Th17 cells. After FMN treatment, there was a significantly increased number of Treg cells and a decreased number of Th17 cells. Additionally, FMN remarkably down-regulated the expression levels of PI3K and Akt proteins in immune-mediated BMF mice. CONCLUSIONS: FMN alleviates immune-mediated BMF by modulating the balance of Treg/Th17 cells through the PI3K/Akt signaling pathway.

The role of TIM3+ NK and TIM3- NK cells in the immune pathogenesis of severe aplastic anemia.

Background: Natural killer (NK) cells play important immunoregulatory roles in the immune pathogenesis of severe aplastic anemia (SAA). Our previous research showed that SAA caused a decrease in T cell immunoglobulin mucin-3 (TIM3) expression on NK cells. Here we investigated the expression of surface receptors, and the cytotoxicity of peripheral TIM3+ NK and TIM3- NK cells in patients with SAA. Methods: The expressions of surface receptors and cytoplasmic protein of TIM3+ NK and TIM3- NK cells from peripheral blood were detected by FCM. The functions of mDCs, and apoptosis rate of K562 cells after co-culture with TIM3+ NK and TIM3- NK cells were maesured by FCM. Westren-blot was used to detect the changes of TIM3+ NK and TIM3- NK signaling pathway proteins (AKT, P-AKT) and compare the functional activity of the two groups. Results: Activating receptors NKG2D and Granzyme B were higher, while inhibiting receptors NKG2A, CD158a and CD158b were lower on TIM3- NK cells compared with TIM3+ NK cells in patients with SAA. In SAA, the expression of CD80 and CD86 on mDCs (Myeloid dendritic cells) was significantly decreased after incubation with TIM3- NK cells. The apoptosis rate (AR) of K562 cells was significantly increased after being incubated with TIM3- NK cells in SAA. The level of signal pathway protein AKT of TIM3- NK cells in SAA was similar to that of TIM3+ NK cells, and the levels of P-AKT and P-AKT/AKT ratio of TIM3- NK cells were significantly higher than those of TIM3+ NK cells. Conclusions: Therefore, TIM3 exerts its inhibitory effect on NK cells and participates in the immune pathogenesis of SAA. Low expression of TIM3 contributes to the enhancement of NK cell activity which in turn inhibits the immune activation state of SAA and improves the disease state. Our research may aid the development of new therapeutic strategies based on TIM3-NK cells infusion for the treatment of SAA.

Haploidentical Hematopoietic Stem Cell Transplantation for Patients with Severe Aplastic Anemia-Single-Centre Experience.

Severe aplastic anemia (SAA) is a life-threatening type of aplastic anemia for which allogeneic stem cell transplantation or immunosuppressive therapy are the principal treatment modalities. Only about 25-30% of patients have a matched sibling donor, and finding an unrelated donor in ethnic minorities is a challenge. The use of related haploidentical donor transplants in severe aplastic anemia is uncommon. We would like to report our experience with the first four patients who underwent haploidentical transplants for severe aplastic anemia. This is a retrospective study. We collected data from our transplant database of all haploidentical hematopoietic stem cell transplants for SAA from 1 January 2020 to 31 December 2021. The transplant protocol used was the Hopkins' protocol. There were three patients who underwent haploidentical transplants as primary therapy for SAA. A fourth patient received a haploidentical transplant after immunosuppressive therapy failure. The median age of the patients at transplant was 24 y (range 20-29). All patients were engrafted. Neutrophil engraftment occurred at a median of 21 days (range 17-22). Any active infections resolved with the recovery of blood counts. The median hospitalization time was 27 days (range 22-41). Only one patient had grade 2 acute GVHD involving the skin. There was no chronic GVHD. All patients had complete lymphoid and myeloid donor chimerism on day 60. Based on our experience and the emerging literature, haplo-identical transplantation should be considered for select young patients with SAA who have low chances of responding to immunosuppressive therapy.

Co-transplantation of umbilical cord mesenchymal stem cells and peripheral blood stem cells in children and adolescents with refractory or relapsed severe aplastic anemia.

To evaluate the co-transplantation efficacy of umbilical cord mesenchymal stem cells (UC-MSCs) and peripheral blood stem cells (PBSCs) as a novel approach for refractory or relapsed severe aplastic anemia (R/R SAA) in children and adolescents, thirty-two children and adolescents diagnosed with R/R SAA underwent a retrospective chart review. The patients were categorized into two groups based on the source of PBSCs: the matched sibling donor (MSD) group and the unrelated donor (UD) group. No adverse events related to UC-MSC infusion occurred in any of the patients. The median time for neutrophil engraftment was 13 days (range: 10-23 days), and for platelets, it was 15 days (range: 11-28 days). Acute GVHD of Grade I-II and moderate chronic GVHD were observed in 21.8 and 12.5% of cases, respectively. No statistically significant differences were found between the MSD and UD groups in terms of engraftment, GVHD, and complications, including infection and hemorrhagic cystitis. The median follow-up time was 38.6 months (range: 1.4-140.8 months). As of October 31, 2021, five patients had succumbed, while 27 (84.4%) survived. The 5-year OS rate showed no statistically significant difference between the MSD and UD groups (84.8 ± 10.0 vs. 82.4 ± 9.2%, p = 0.674). In conclusion, the application of UC-MSCs in the treatment of R/R SAA in PBSC transplantation is reliable and safe, they had no graft rejection, low incidence of severe GVHD which may have been contributed by the co-infusion of MSC.

Unraveling trajectories from aplastic anemia to hematologic malignancies: genetic and molecular insights.

Background: Aplastic anemia (AA), characterized by hematopoietic stem cell deficiency, can evolve into different hematologic malignancies. Our understanding of the genetic basis and mechanisms of this progression remains limited. Methods: We retrospectively studied 9 acquired AA patients who later developed hematologic malignancies. Data encompassed clinical, laboratory, karyotype, and next-generation sequencing (NGS) information. We explored chromosomal alterations and mutation profiles to uncover genetic changes underlying the transition. Results: Nine AA patients developed myelodysplastic syndrome (seven patients), acute myeloid leukemia (one patient), or chronic myelomonocytic leukemia (one patient). Among eight patients with karyotype results at secondary malignancy diagnosis, monosomy 7 was detected in three. Trisomy 1, der(1;7), del(6q), trisomy 8, and del(12p) were detected in one patient each. Among three patients with NGS results at secondary malignancy diagnosis, KMT2C mutation was detected in two patients. Acquisition of a PTPN11 mutation was observed in one patient who underwent follow-up NGS testing during progression from chronic myelomonocytic leukemia to acute myeloid leukemia. Conclusion: This study highlights the genetic dynamics in the progression from AA to hematologic malignancy. Monosomy 7's prevalence and the occurrence of PTPN11 mutations suggest predictive and prognostic significance. Clonal evolution underscores the complexity of disease progression.