Myelodysplastic syndromes (MDS) are a heterogeneous group of pre-leukemic hematopoietic disorders characterized by cytopenia in peripheral blood due to ineffective hematopoiesis and normo- or hypercellularity and morphologic dysplasia in bone marrow (BM). An inflammatory BM microenvironment and programmed cell death of hematopoietic stem/progenitor cells (HSPCs) are thought to be the major causes of ineffective hematopoiesis in MDS. Pyroptosis, apoptosis and necroptosis (collectively, PANoptosis) are observed in BM tissues of MDS patients, suggesting an important role of PANoptosis in MDS pathogenesis. Caspase 8 (Casp8) is a master regulator of PANoptosis, which is downregulated in HSPCs from most MDS patients and abnormally spliced in HSPCs from MDS patients with SRSF2 mutation. To study the role of PANoptosis in hematopoiesis, we generated inducible Casp8 knockout mice (Casp8-/-). Mx1-Cre-Casp8-/- mice died of BM failure within 10 days of polyI:C injections due to depletion of HSPCs. Rosa-ERT2Cre-Casp8-/- mice are healthy without significant changes in BM hematopoiesis within the first 1.5 months after Casp8 deletion. Such mice developed BM failure upon infection or low dose polyI:C/LPS injections due to the hypersensitivity of Casp8-/- HSPCs to infection or inflammation-induced necroptosis which can be prevented by Ripk3 deletion. However, impaired self-renewal capacity of Casp8-/- HSPCs cannot be rescued by Ripk3 deletion due to activation of Ripk1-Tbk1 signaling. Most importantly, mice transplanted with Casp8-/- BM cells developed MDS-like disease within 4 months of transplantation as demonstrated by anemia, thrombocytopenia and myelodysplasia. Our study suggests an essential role for a balance in Casp8, Ripk3-Mlkl and Ripk1-Tbk1 activities in the regulation of survival and self-renewal of HSPCs, the disruption of which induces inflammation and BM failure, resulting in MDS-like disease.

Arthritis causes Fos-like 2 (Fosl2) inactivation, and various immune cells contribute to its pathogenesis. However, little is known about the role of Fosl2 in hematopoiesis and the possible pathological role of Fosl2 inactivation in the hematopoietic system in arthritis. In this study, we show that Fosl2 maintains hematopoietic stem cell (HSC) quiescence and differentiation while controlling the inflammatory response via macrophages. Fosl2-specific deletion in the hematopoietic system caused the expansion of HSCs and myeloid cell growth while affecting erythroid and B cell differentiation. Fosl2 inactivation enhanced macrophage M1 polarization and stimulated proinflammatory cytokines and myeloid growth factors, skewing HSCs toward myeloid cell differentiation, similar to hematopoietic alterations in arthritic mice. Loss of Fosl2 mediated by Vav-iCre also displays an unexpected deletion in embryonic erythro-myeloid progenitor-derived osteoclasts, leading to osteopetrosis and anemia. The reduced bone marrow cellularity in Vav-iCreFosl2f/f mice is a consequence of the reduced bone marrow space in osteopetrotic mice rather than a direct role of Fosl2 in hematopoiesis. Thus, Fosl2 is indispensable for erythro-myeloid progenitor-derived osteoclasts to maintain the medullary cavity to ensure normal hematopoiesis. These findings improve our understanding of the pathogenesis of bone-destructive diseases and provide important implications for developing therapeutic approaches for these diseases.

The MRE11-RAD50-NBN (MRN) complex plays a key role in recognizing and signaling DNA double-strand breaks. Pathogenic variants in NBN and MRE11 give rise to the autosomal-recessive diseases, Nijmegen breakage syndrome (NBS) and ataxia telangiectasia-like disorder, respectively. The clinical consequences of pathogenic variants in RAD50 are incompletely understood. We aimed to characterize a newly identified RAD50 deficiency/NBS-like disorder (NBSLD) patient with bone marrow failure and immunodeficiency.
We report on a girl with microcephaly, mental retardation, bird-like face, short stature, bone marrow failure and B-cell immunodeficiency. We searched for candidate gene by whole-exome sequencing and analyzed the cellular phenotype of patient-derived fibroblasts using immunoblotting, radiation sensitivity assays and lentiviral complementation experiments.
Compound heterozygosity for two variants in the RAD50 gene (p.Arg83His and p.Glu485Ter) was identified in this patient. The expression of RAD50 protein and MRN complex formation was maintained in the cells derived from this patient. DNA damage-induced activation of the ATM kinase was markedly decreased, which was restored by the expression of wild-type (WT) RAD50. Radiosensitivity appeared inconspicuous in the patient-derived cell line as assessed by colony formation assay. The RAD50R83H missense substitution did not rescue the mitotic defect in complementation experiments using RAD50-deficient fibroblasts, whereas RAD50WT did. The RAD50E485X nonsense variant was associated with in-frame skipping of exon 10 (p.Glu485_545del).
These findings indicate important roles of RAD50 in human bone marrow and immune cells. RAD50 deficiency/NBSLD can manifest as a distinct inborn error of immunity characterized by bone marrow failure and B-cell immunodeficiency.

Unrelated umbilical cord blood transplantation (UCBT) for bone marrow failure (BMF) disorders using conditioning regimens without Anti-Thymocyte Globulin (ATG) has been used as an alternative transplantation for emerging patients without matched-sibling donors. Experience with this transplant modality in children is limited, especially as a secondary treatment for transplant failure patients.
We retrospectively reviewed 17 consecutive bone marrow failure patients who underwent unrelated umbilical cord blood transplantation in our center and received conditioning regimens of Total Body Irradiation (TBI) or Busulfan (BU) + Fludarabine (FLU) + Cyclophosphamide (CY).
Among the 17 BMF patients, 15 patients were treated with first cord blood transplantation and another 2 with secondary cord blood transplantation because of graft failure after first haploidentical stem cell transplantation at days +38 and +82. All patients engrafted with a median donor cell chimerism of 50 % at days +7 (range, 16 %-99.95 %) and finally rose to 100 % at days +30. Median time to neutrophil engraftment was 19 days (range, 12-30) and time to platelet engraftment was 32 days (range, 18-61). Pre-engraftment syndrome (PES) was found in 16 patients (94.11 %, 16/17). Cumulative incidence of grades II to IV acute GVHD was 58.8 % (95 % CI: 32.7-84.9 %), and 17.6 % (95 % CI: 2.6-37.9 %) of patients developed chronic GVHD. The 3-year overall survival (OS) and failure-free survival (FFS) rates were 92.86 ± 6.88 %.
UCBT is an effective alternative treatment for bone marrow failure pediatric patients. TBI/BU + FLU + CY regimen ensure a high engraftment rate for unrelated umbilical cord blood transplantation, which overcomes the difficulty of graft failure. Secondary salvage use of cord blood transplantation may still be useful for patients who have failed after other transplantation.

BACKGROUND: T-cell immunoglobulin and mucin-containing domain (TIM)-3 exerts its inhibitory effect on NK cells and participates in the immune pathogenesis of SAA. In this study, we aimed to explore a novel treatment method of TIM-3(+) NK or TIM-3(-) NK cell infusion in combination with immunosuppressive therapy for bone marrow failure (BMF)/aplastic anemia (AA) mice.
METHODS: BMF/AA mouse model was constructed. The TIM-3 expression and functional molecules on TIM-3(+) and TIM-3(-) NK cells of the BMF group, total body irradiation (TBI) group, and normal control (NC) group mice were detected by flow cytometry. After treatment, the general condition, whole blood cell and bone marrow cell (BMC) count, and immune condition of mice from each group were compared.
RESULTS: TIM-3 expression in the peripheral blood NK cells of BMF mice was significantly lower than that of the TBI and NC group mice. TIM-3(-) NK cells expressed more NKG2D receptors than TIM-3(+) NK cells. The levels of P-Akt and PI3K in TIM-3(-) NK cells were higher than those in TIM-3(+) NK cells. On the 17th day after BMF induction, the weight, peripheral whole blood cell count, and BMC count of BMF mice decreased significantly compared with that of the NC group mice. The therapeutic effect in the TIM-3(-) NK cell treatment group was better than that in the TIM-3(+) NK cell treatment and CsA treatment groups. Concurrently, the ratio of CD4+ T and CD8+ T cells of BMF mice was significantly lower than that of the NC group mice. The therapeutic effect in CsA + TIM-3(-) NK group was more significant than that of the CsA treatment and the CsA + TIM-3(+) NK groups.
CONCLUSIONS: In this study, we found that the general condition, peripheral whole blood cell and BMC count, and immune status of BMF mice improved significantly after CsA + TIM-3(-) NK cell treatment. These results may provide further insights into the immune pathogenesis of SAA and novel therapeutic ideas for improving SAA treatment.

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Objective: The clinical and genetic characteristics of a child with inherited bone marrow failure syndrome as prominent clinical manifestations and special facial features were analyzed, and the etiology and mechanism were explored in, combination with clinical practice. Methods: Blood samples and clinical information were collected separately from the proband and their biological parents. The pathogenic variant was verified using next-generation sequencing technology screening, and the candidate variable sites were confirmed by using Sanger sequencing among all members of the family. Results: A heterozygous nonsense mutation in exon 17 of KAT6A (NM_006766), c.4177G > T (p.E1393*) predicted to cause truncation within the acidic domain of the protein was identified. Pedigree analysis did not reveal any variation in this locus between the proband\'s father and mother. No report of this pathogenic variant was found in a literature search of domestic and foreign databases, indicating that it is a newly discovered mutation. According to the guidelines of the American College of Medical Genetics, the variation was preliminarily determined to be a pathogenic. The newly discovered heterozygous mutation in KAT6A may be the cause of the disease in this child. Additionally, inherited bone marrow failure syndrome is a prominent manifestation. Conclusion: This study not only provides us with an in-depth understanding of this rare syndrome but also deepens our understanding of the function of KAT6A.

Objective: Diagnostic value assessment of sternal bone marrow cell morphology in patients with acquired hypocellular bone marrow failure syndromes (BMFS) characterized by normal cytogenetics. Methods: A total of 194 eligible patients with an acquired hypocellular BMFS pre-sternum diagnosis in Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Science & Peking Union Medical College from June 2014 to January 2019 were reviewed. Sternal bone marrow evaluation was performed, and a post-sternum diagnosis was made. Clinical characteristics and overall survival (OS) were then compared among patients with different post-sternum diagnosis. Binary logistic regression was used to develop a predictive scoring system. Results: In 152 patients with pre-sternum AA diagnosis, 29 patients with a pre-sternum idiopathic cytopenia of undetermined significance (ICUS) diagnosis, and 13 patients with a pre-sternum clonal cytopenia of undetermined significance (CCUS) diagnosis, sternal bone marrow evaluation resulted in a change of diagnosis to hypocellular myelodysplastic syndrome (hypo-MDS) in 42.8% (65/152) , 24.1% (7/29) , and 30.8% (4/13) , respectively. Patients with a post-sternum hypo-MDS diagnosis showed a significant difference in OS compared with patients with a post-sternum AA diagnosis (P=0.005) . Patients with ICUS/CCUS showed no difference in OS compared with AA and hypo-MDS (P=0.095 and P=0.480, respectively) . A 4-item predictive scoring system to identify hypocellular BMFS patients that need sternal bone marrow evaluation was developed, including age > 60 years old (OR=6.647, 95% CI 1.954-22.611, P=0.002, 2 points) , neutrophil alkaline phosphatase score ≤ 160 (OR=2.654, 95% CI 1.214-5.804, P=0.014, 1 point) , abnormal erythroid markers evaluated by flow cytometry on iliac bone marrow (OR=6.200, 95% CI 1.165-32.988, P=0.032, 2 points) , and DAT (DNMT3A, ASXL1, TET2) genes mutation (OR=4.809, 95% CI 1.587-14.572, P=0.005, 1 point) . The Akaike information criterin (AIC) was 186.1. Conclusion: Patients with a pre-sternum acquired hypocellular BMFS diagnosis characterized by normal cytogenetics may not reach accurate diagnostic categorization without sternal bone marrow cell morphology evaluation, which could be considered a diagnostic tool for this patient population. A predictive scoring system was developed, and when the total score is ≥ 2 points, sternal bone marrow evaluation should be performed for accurate diagnostic categorization that is critical to optimal patient care.
目的： 探讨胸骨骨髓细胞形态学在基于髂骨穿刺骨髓细胞形态学和骨髓活检组织切片细胞形态学表现为染色体核型正常获得性低增生性骨髓衰竭综合征（BMFS）患者的诊断价值。 方法： 回顾性分析2014年6月至2019年1月中国医学科学院血液病医院（中国医学科学院血液学研究所）初诊的194例获得性低增生性BMFS患者的临床资料，结合胸骨骨髓细胞形态学结果重新诊断分型，分析各诊断分型患者的临床特征及预后差异。通过Logistic回归进行多因素分析，建立推荐该类患者进行胸骨骨髓细胞形态学分析的积分系统。 结果： 194例染色体核型正常的获得性低增生性BMFS患者，基于髂骨骨髓检查结果初步诊断为再生障碍性贫血（AA） 152例，意义未明的特发性血细胞减少症（ICUS）29例，意义未明的克隆性血细胞减少症（CCUS）13例，结合胸骨骨髓细胞形态学结果后分别有42.8%（65/152）、24.1%（7/29）和30.8%（4/13）患者最终诊断为低增生型骨髓增生异常综合征（hypo-MDS）。胸骨骨髓检查结果最终诊断为AA与hypo-MDS患者总生存率差异有统计学意义（P＝0.005）。对结合胸骨骨髓检查结果最终诊断为AA和hypo-MDS两组患者临床特征、外周血血细胞参数和髂骨骨髓实验室特征进行单因素及多因素分析结果表明，年龄>60岁（OR＝6.647，95%CI 1.954~22.611，P＝0.002，积2分）、NALP阳性指数≤160（OR＝2.654，95%CI 1.214~5.804，P＝0.014，积1分）、髂骨骨髓流式红系表型异常（OR＝6.200，95%CI 1.165~32.988，P＝0.032，积2分）及有DAT（DNMT3A、ASXL1、TET2）基因突变（OR＝4.809，95%CI 1.587~14.572，P＝0.005，积1分）均为影响染色体核型正常的获得性低增生性BMFS患者结合胸骨骨髓细胞形态学分析后诊断为hypo-MDS的独立预测因素。使用赤池信息准则（AIC）对模型进行预测效能评估，AIC＝186.1。当积分≥2分时诊断为hypo-MDS的特异性为91.7%，阳性预测值为80.6%。 结论： 染色体核型正常的获得性低增生性BMFS患者，仅通过髂骨骨髓细胞形态学和骨髓活检组织病理学可能产生误诊。我们提出一项积分系统，当积分≥2分时强烈建议该类患者进行胸骨骨髓细胞形态学检查有助于明确诊断分型。.

Most of the studies on functional outcomes in pediatric survivors of cancers and bone marrow failure disorders have been conducted in North American, European, and Oceanian populations, with few studies having been performed in China. The objective of this study was to evaluate psychosocial outcomes in a cohort of Chinese pediatric survivors diagnosed with cancer or conditions requiring hematopoietic stem cell transplantation (HSCT), and to identify clinical and behavioral factors associated with adverse psychosocial outcomes.
This was a cross-sectional survey study. We recruited pediatric survivors of cancer or inherited disorder requiring HSCT at ≤18 years old and were ≥6 months post-treatment. Parents completed the St. Jude Children\'s Research Hospital After Completion of Therapy questionnaire to report their child\'s emotional functioning, social functioning, attention/concentration and behavior. Multivariable general linear modeling was used to identify clinical, treatment and behavioral factors associated with psychosocial outcomes, adjusting for sex, age and cancer diagnoses.
Ninety-five pediatric survivors were recruited (62.1% male; mean [standard deviation] age 9.7 [3.4] years; 4.1 [2.6] years post-diagnosis). They were diagnosed with bone marrow failure disorders (23.2%), hematological malignancies (45.3%) or solid tumors (23.2%). Compared with survivors with no current health problems, those with more than one current health problem performed worse in emotional functioning (Estimate = 2.42, SE = 0.88, P = 0.008) and social functioning (Estimate = 2.90, SE = 1.64, P = 0.03). Higher pain interference was significantly associated with worse emotional functioning (Estimate = 0.19, SE = 0.08, P = 0.03) and attention functioning (Estimate = 0.26, SE = 0.11, P = 0.03). Compared with survivors who reported less sleep problems, those who had more sleep problems demonstrated poorer emotional functioning (Estimate = 0.30, SE = 0.08, P = 0.001). Survivors who had a longer duration of screen usage per day reported more impairment on attention and behavior functioning than those who had a shorter duration of screen usage per day (both P<0.5).
Survivors who were diagnosed at a younger age or had unaddressed/untreated health problems may require additional psychological evaluation. The implementation of psychosocial assessments during routine long-term follow-up care may help to identify high-risk patients during the early phase of survivorship. Rehabilitation interventions should address modifiable behavioral factors (e.g. sleep habits, screen time and chronic pain).

Broader genetic screening has led to the growing recognition of the role of germline variants associated with adult bone marrow failure (BMF) and myeloid neoplasia (MN) not exclusively in children and young adults. In this study, we applied a germline variant panel to 3008 adult BMF and MN cases to assess the importance of germline genetics and its impact on disease phenotype and prognosis. In our cohort, up to 9.7% of BMF and 5.3% of MN cases carried germline variants. Our cohort also included heterozygous carriers of recessive traits, suggesting they contribute to the risk of BMF and MN. By gene category, variants of Fanconi anemia gene family represented the highest-frequency category for both BMF and MN cases, found in 4.9% and 1.7% cases, respectively. In addition, about 1.4% of BMF and 0.19% of MN cases harbored multiple germline variants affecting often functionally related genes as compound heterozygous. The burden of germline variants in BMF and MN was clearly associated with acquisition of monosomy 7. While BMF cases carrying germline variants showed similar overall survival as compared to the wild-type (WT) cases, MN cases with germline variants experienced a significantly shorter overall survival as compared to WT cases.