American Journal of Hematology最新文献

PIEZO1 encodes a mechanoreceptor, a cation channel activated by mechanical stimuli. Gain-of-function (GoF) variants in PIEZO1 cause dehydrated hereditary stomatocytosis (DHS), or xerocytosis, a pleiotropic syndrome characterized by anemia and iron overload. DHS patients develop hepatic iron overload independent of the degree of anemia and transfusion regimen. PIEZO1-GoF variants suppress hepcidin expression in both hepatic cellular model and constitutive/macrophage-specific Piezo1-GoF mice model. Therefore, PIEZO1-GoF variants regulate hepcidin expression by a crosstalk between hepatocytes (HCs) and macrophages with a still unknown mechanism. Transcriptomic and proteomics analysis in the human hepatic Hep3B cells engineered for the PIEZO1-R2456H variant (PIEZO1-KI) revealed alterations in the actin cytoskeleton regulation, MAPK cascade, and RAS signaling. These changes mainly occur through a novel key regulator, RRAS, whose protein and mRNA levels are regulated by PIEZO1 activation and inhibition. This regulation was further confirmed in C57BL/6 mouse primary HCs treated with Yoda-1 and/or GsMTx-4. Indeed, PIEZO1-KI cells exhibited hyper-activated RAS-GTPase activity that is rescued by PIEZO1 inhibition, restoring expression of the hepcidin gene HAMP. A negative correlation between RAS signaling and HAMP regulation was confirmed by inhibiting RAS-GTPase and MEK1-2 activity. Conversely, rescued HAMP gene expression requires downregulation of RRAS, confirming negative feedback between RAS-MAPK and BMP/SMADs pathways in HAMP regulation. We demonstrated that PIEZO1-GoF variants influence the actin cytoskeleton organization by activating the hepatic RAS signaling system. Understanding the role of RAS signaling in regulating iron metabolism could pave the way for new therapeutic strategies in DHS and other conditions characterized by iron overload.

Acute myeloid leukemia (AML) with translocation t(8;16)(p11;p13) represents a rare entity that has been categorized as a disease-defining recurring cytogenetic abnormality with adverse risk in the 2022 European LeukemiaNet classification. This rating was mainly based on a retrospective analysis comprising patients from several large clinical trials, which, however, included only 21 patients treated with allogeneic stem cell transplantation (alloSCT). Therefore, the European Society for Blood and Marrow Transplantation performed a registry study on a larger cohort to evaluate the role of alloSCT in t(8;16) AML. Sixty transplant recipients with t(8;16) AML were identified. Two-year overall and leukemia-free survival (OS/LFS) was 43/39%. Patients transplanted in first complete remission (CR1, n = 44) achieved a 2-year OS/LFS of 48%/48%. Following alloSCT in CR1, the multivariable analysis identified a complex karyotype (CK) as a major risk factor for relapse (HR 4.17, p = .016), lower LFS (HR 3.38, p = .01), and lower OS (HR 3.08, p = .017). Two-year OS/LFS of patients with CK was 19%/19%, in contrast to 67%/67% in patients with t(8;16) outside a CK. Other factors for inferior outcomes were older age and secondary AML. In summary, alloSCT could mitigate the adverse risk of patients with t(8;16) AML not harboring a CK, particularly when performed in CR1.

According to current recommendations, older AML patients in first complete remission (CR) after induction chemotherapy should receive consolidation with intermediate-dose cytarabine (IDAC). However, no study has demonstrated the superiority of IDAC over other regimen. In this retrospective study, we compared the efficacy of mini-consolidations (idarubicin 8 mg/m² day 1, cytarabine 50 mg/m²/12 h, day 1–5) and IDAC. Inclusion criteria were newly diagnosed AML, age > 60 years, first CR after induction and at least 1 cycle of consolidation. Of the 796 included patients, 322 patients received mini-consolidations and 474 patients received IDAC. Mini-consolidation patients were older, and more often, they had de novo AML and unfavorable risk. The rate of allogeneic transplantation was higher in the IDAC group. The median number of cycles was higher in the mini-consolidation group (4 vs. 2; p < .0001). Median relapse-free survival was 18 months with mini-consolidations and 12 months with IDAC (p = .0064). In multivariate analysis, the risk of relapse or death was significantly higher in the IDAC group (p = .004). Median OS was 36 versus 31 months with mini-consolidations or IDAC, respectively (p = .46). In multivariate analysis, the consolidation regimen had no significant influence on OS (p = .43). In older AML patients, post-remission therapy with mini-consolidations represents an alternative to IDAC.

High-grade B-cell lymphoma not otherwise specified (HGBCL, NOS) has overlapping morphological and genetic features with diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL), leading to uncertainty in its diagnosis and clinical management. Using functional genomic approaches, we previously characterized HGBCL and NOS, that demonstrate gene expression profiling (GEP), and genetic signatures similar to BL. Herein, we characterize distinct HGBCL, NOS, cohort (n = 55) in adults (n = 45) and in children (n = 10), and compared the GEP, genomic DNA copy number (CN), and mutational spectrum with de novo DLBCL (n = 85) and BL (n = 52). This subgroup, representing ~60% of HGBCL, NOS, lack gene-expression signature of BL and double hit/dark zone lymphoma, but express DLBCL like signatures and are characterized by either GCB- or ABC-like mRNA signatures and exhibit higher genomic complexity, similar to de novo DLBCL, and show alteration in genes regulating B-cell activation (CD79B, MYD88, PRDM1, TBLIXR1, CARD11), epigenome (KMT2D, TET2) and cell cycle transition (TP53, ASPM). However, recurrent mutations in genes often mutated in BL (DDX3X, GNA13, CCND3), but rare in DLBCL, are also present in HGBCL-NOS, highlighting genetic heterogeneity. Consistent with mutation spectrum, frequent genomic CN alterations in genes regulating B-cell activation (del-PRDM1, gain-BCL6, -REL, -STAT3) and cell cycle regulators (del-TP53, del-CDKN2A, del-RB1, gain-CCND3) were observed. Pediatric cases showed GCB-DLBCL-like mRNA signatures, but also featured hallmark mutations of pediatric BL. Frequent oncogenic PIM1 mutations were present in adult HGBCL, NOS. In vitro analyses with pharmacologic or genetic inhibition of PIM1 expression triggered B-cell activation and NF-κB-induced apoptosis, suggesting that PIM1 is a rational therapeutic target.

Relapse is the major cause of treatment failure in Philadelphia chromosome-positive (Ph⁺) acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study aimed to evaluate the effect of a prophylactic tyrosine kinase inhibitor (TKI) strategy on relapse in this population. Patients were assigned to prophylactic or control groups based on measurable residual disease (MRD) pre-transplantation. The primary endpoint was the cumulative incidence of relapse. A total of 110 patients with Ph⁺ ALL undergoing allo-HSCT were enrolled in this prospective study. Thirty-eight patients with positive MRD pre-transplantation were included in the prophylactic group, and 72 with negative MRD pre-transplantation were included in the control group. The 4-year cumulative incidence of relapse was 25.3% (95% CI: 12.1%–41.0%) and 20.3% (11.6%–30.7%; HR = 1.272, 95% CI: 0.551–2.940, p = .549), and non-relapse mortality was 10.5% (3.3%–22.7%) and 9.7% (4.2%–17.9%; HR = 1.094, 95% CI: 0.320–3.738, p = .928) in the prophylactic and control groups. The 4-year overall survival was 71.8% (53.2%–84.1%) and 84.1% (72.9%–90.9%; HR = 1.746, 95% CI: 0.741–4.112, p = .196), and leukemia-free survival was 64.1% (45.8%–77.7%) and 70.0% (57.6%–79.4%; HR = 1.212, 95% CI: 0.607–2.421, p = .585) in the prophylactic and control groups. Our results suggest that prophylactic TKI post-HSCT in patients with positive MRD pre-transplantation can produce outcomes comparable to negative MRD pre-transplantation without TKI post-HSCT.

The impact of measurable residual disease (MRD) in relapse/refractory multiple myeloma (RRMM) patients treated with T-cell redirecting immunotherapy is uncertain. We analyzed MRD dynamics using next-generation flow in 201 patients treated in clinical trials with chimeric antigen receptor (CAR) T cells and T-cell engagers (TCE). Achieving MRD negativity at 10⁻⁶ was associated with 89% reduction in the risk of progression and/or death. Survival outcomes were improved in patients with sustained versus transient MRD negativity and were dismal in those who remained MRD positive. The intent-to-treat MRD negative rates were higher in patients treated with CAR T cells versus TCE. However, among patients achieving MRD negativity, there were no differences in survival outcomes when stratified according to treatment with CAR T cells versus TCE. In multivariate analysis including the number of prior lines of treatment, International Staging System, cytogenetic risk, extramedullary disease and type of T-cell redirecting immunotherapy, only the complete remission (CR) and MRD statuses showed independent prognostic value for progression-free and overall survival. In conclusion, our study shows that deep and sustained MRD negative CR is the most relevant prognostic factor and should be considered as the treatment endpoint in RRMM patients treated with CAR T cells and TCE.

A 76-year-old man with a history of chronic obstructive pulmonary disease with lung fibrosis, type 2 diabetes mellitus, and chronic kidney disease underwent computed tomography imaging of the chest due to increasing dyspnea. The bones appeared sclerotic, and a bone scan showed diffuse tracer uptake throughout the axial and appendicular skeleton. The prostate showed no features of malignancy on magnetic resonance imaging and prostate-specific antigen was 6.6 μg/L (normal range (NR) 0–5). Serum tryptase levels were mildly elevated at 16 μg/L (NR 2–14) on two occasions. Biochemical investigations showed vitamin D < 14 nmol/L (NR > 50), alkaline phosphatase 665 U/L (NR 30–130), parathyroid hormone 52.8 pmol/L (NR 1.6–7.5), calcium 2.43 mmol/L (NR 2.2–2.6) and phosphate 1.07 mmol/L (NR 0.8–1.5), in keeping with hyperparathyroidism secondary to vitamin D deficiency and chronic kidney disease (creatinine 169 μmol/L and estimated glomerular filtration rate 34 mL/min).

Bone marrow trephine biopsy sections showed areas of active bone resorption by multinucleate osteoclasts forming recesses known as Howship's lacunae (top and bottom left, all histological images hematoxylin and eosin, ×50 objective). In other areas, lamellar bone was being actively laid down by rows of osteoblasts (top center). There was patchy fibrosis at sites of previous bone resorption (bottom center). Notably, there were osteoclasts also visible in the marrow aspirate (top and bottom right, May–Grünwald–Giemsa, ×100 objective). There was no abnormal mast cell population.

These features are typical of hyperparathyroidism where osteoclasts strive to release calcium whilst osteoblasts attempt to repair the trabecular damage. This active bone remodeling with the associated trabecular changes generates the sclerotic radiological appearance of the affected bones. Osteoblasts and osteoclasts normally work together in bone repair, remodeling, and growth but this process is exaggerated under the influence of increased parathyroid hormone whether primary, due to a parathyroid adenoma, or secondary, as a result of vitamin D deficiency or chronic kidney disease. The recognition of the features of bone disorders with associated bone marrow fibrosis is important so that they are not confused with myeloproliferative neoplasms.