Blood advances最新文献

The pursuit of ex vivo erythrocyte generation has led to the development of various culture systems that simulate the bone marrow microenvironment. However, these models often fail to fully replicate the hematopoietic niche's complex dynamics. In our research, we employ a comprehensive strategy that emphasizes physiological red blood cell (RBC) differentiation using a minimal cytokine regimen. A key innovation in our approach is the integration of a three-dimensional (3D) silk-based scaffold engineered to mimic both the physical and chemical properties of human bone marrow. This scaffold facilitates critical macrophage-RBC interactions and incorporates fibronectin functionalization to support the formation of erythroblastic island (EBI)-like niches. We observed diverse stages of erythroblast maturation within these niches, driven by the activation of autophagy, which promotes organelle clearance and membrane remodeling. This process leads to reduced surface integrin expression and significantly enhances RBC enucleation. Using a specialized bioreactor chamber, millions of RBCs can be detached from the EBIs and collected in transfusion bags via dynamic perfusion. Inhibition of autophagy through pharmacological agents or alpha4 integrin blockade, disrupted EBI formation, preventing cells from completing their final morphological transformations and remaining trapped in the erythroblast stage. Our findings underscore the importance of the bone marrow niche in maintaining the structural integrity of EBIs and highlight the critical role of autophagy in facilitating organelle clearance during RBC maturation. RNA sequencing analysis further confirmed that these processes are uniquely supported by the 3D silk scaffold, which is essential for enhancing RBC production ex vivo.

Dysregulated JAK/STAT signaling underlies the pathogenesis of myelofibrosis, a myeloproliferative neoplasm characterized by cytopenias, splenomegaly and constitutional symptoms. JAK inhibitors, such as fedratinib, are the primary therapeutic option for patients with high-risk or symptomatic myelofibrosis. Fedratinib has characteristics that distinguish it from the other commercially available JAK inhibitors, such as its preferential inhibition of JAK2 and its inhibitory effects on kinases such as FLT3 and BRD4. Fedratinib is most often used in the second-line setting after intolerance or resistance to other JAK inhibitors, but there is substantial evidence that it is an effective first-line option in the appropriate patient population. Prevention and early treatment of fedratinib-related gastrointestinal toxicity is key to maintaining adequate drug exposure, and clinicians must remain vigilant for Wernicke encephalopathy during treatment. Fedratinib's JAK2 selectivity and kinome profile make it an appealing agent for alternative indications, such as myelodysplastic/myeloproliferative neoplasms and maintenance after bone marrow transplantation, which are under active investigation.

Selective targeting of the functionally exhausted malignant T cells in cutaneous T-cell lymphoma (CTCL) and distinct cells within the tumor microenvironment (TME) via PD1/PD-L1 blockade (durvalumab) may restore an anti-tumor immune response. The oral immunomodulator lenalidomide, which has activity in CTCL, may enhance durvalumab immune checkpoint blockade. Our phase 1/2 clinical trial of durvalumab and lenalidomide in patients with refractory/advanced CTCL (NCT03011814) sought to assess safety and tolerability and identify the maximum tolerated dose/recommended phase 2 dose (RP2D) of lenalidomide plus fixed-dose durvalumab. Secondary and tertiary objectives were to investigate efficacy and effects on the TME. Thirteen patients were evaluable for toxicities and 12 for dose decisions and response. No serious adverse events (SAEs) or dose-limiting toxicities (DLTs) were observed during cycles 1-3 (DLT evaluation period), and dose level 3 is the RP2D. The most frequent AEs were tumor flare, fatigue, neutropenia, and leukopenia. Three patients developed grade 1/2 autoimmune thyroiditis that resolved with treatment. Best overall and skin response rates were 58.3% (95% CI: 27.7% - 84.8%) and 75% (95% CI: 42.8% - 94.5%) respectively. Median cycles of treatment were 11 (range, 3-42+). Median duration of response was 25.5 (range 8-36.5) months. The combination showed clinical activity with 7 partial responses, and 4 stable disease. Potentially predictive immune signatures were downregulation of TNF-alpha signaling via NFκB, IFN-gamma, and PI3-AKT-mTOR signaling pathways in responders vs up-regulation of MYC targets and pro-inflammatory pathways in non-responders. Profiling of immune cell compositions revealed changes in individual immune cell clusters based on treatment response.

Castleman disease (CD) describes a group of rare lymphoproliferative disorders that exhibit a wide range of symptomatology and degree of lymphadenopathy, particularly across the two forms of CD with unknown etiology, unicentric CD (UCD) and HHV-8-negative/idiopathic multicentric CD (iMCD). Whereas UCD cases typically present with localized lymphadenopathy and mild symptoms, iMCD involves multicentric lymphadenopathy and cytokine-storm driven symptoms with three recognized clinical phenotypes. Increasingly, there are anecdotal reports of cases that do not fit into this framework, but these cases have not been systematically described. Herein, we utilize the ACCELERATE natural history registry to characterize the spectrum of CD based on disease features, symptomatology, and severity. Our results characterize a cohort of 179 CD cases, which were reviewed and confirmed by an expert panel of clinicians and hematopathologists. We show that CD patients present on a continuous spectrum of clinical phenotypes, and we describe oligocentric CD (OligoCD), an intermediate phenotype that does not fit the criteria for UCD or iMCD. These cases tend to have "oligocentric" lymphadenopathy (median [interquartile range] regions of lymphadenopathy: 3.0 [2.0,4.0]) in a regional pattern and exhibit a mild clinical phenotype that is more similar to UCD than iMCD. We also show that OligoCD patients are inconsistently categorized as UCD versus iMCD, highlighting the need for this characterization. Future data collected through ACCELERATE may further elucidate the natural history and risk profile of these patients.

Pathogenic germline variants affecting proper telomere maintenance result in premature telomere shortening and cause telomere biology disorders (TBDs). While classical dyskeratosis congenita in children is rather well defined, late-onset ("cryptic") TBDs remain underrecognized, resulting in underdiagnosis and inadequate treatment in affected adults. Here, we present a series of adult TBD cases collected through the German TBD reference center between 2014 and 2024. Patients ≥18 years with an age-matched telomere length (TL) < 10th percentile in lymphocytes and detection of either a variant of uncertain significance, a pathogenic or a likely pathogenic variant in TBD-associated genes, and available clinical data were included in this analysis. On this basis, a novel point-based algorithm for categorization into proven, probable and suspected-only TBD cases, respectively, was developed. Out of a total of 1,537 TL analyses, 42 patients with proven (n=29) or probable (n=13) TBD were identified. Median age at first clinical manifestation and at diagnosis was 20.0 years and 34.1 years, respectively. Bone marrow failure (BMF) was the most frequent manifestation observed in our cohort (73.8%), followed by liver or interstitial lung diseases (50.0% and 41.5%, respectively). Immunosuppressive therapy was carried out in six patients with BMF, none of them responded. In comparison, eight of eight evaluable patients treated with androgen derivatives showed hematologic response. Our data provide novel real-world insight into the clinical manifestation spectrum, diagnosis as well as clinical course and treatment of TBD in adult, late-onset cases of this hereditary disease.

An unmet clinical need in chronic lymphocytic leukemia (CLL) is emerging due to the rapidly expanding group of patients with double refractory (BTK- and Bcl2-inhibitor) disease. So far, autologous T-cell-based therapies, including chimeric antigen receptor (CAR) T-cells, have limited success in CLL, which has been attributed to an acquired CLL-mediated T-cell dysfunction and subset-skewing towards effector cells at the expense of memory formation. T-cell responses rely on dynamic metabolic processes, particularly mitochondrial fitness. While mitochondrial disruptions have been observed in solid tumor-infiltrating lymphocytes, their impact on T-cell immunity in lymphoproliferative disorders is unknown. Recent findings indicate that mitochondrial mass in CAR T-cells correlates with CLL clinical outcomes. This prompted an investigation into the mitochondrial fitness in CLL T-cells. Integrated metabolic and functional analyses revealed impaired, depolarized mitochondria across all T-cell subsets in untreated CLL patients, leading to further ex vivo and in vivo mouse studies on the underlying signaling alterations. Multi-omics profiling of transcriptome and epigenome revealed significant alterations in mitochondrial signaling, diminished AMP-activated protein kinase (AMPK) and autophagy activity, and upregulated glycolysis coupled with hyperactivation in the Akt kinase. Inhibition of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway during CLL T-cell culture induced metabolic reprogramming, enhancing mitochondrial activity, PPAR-gamma coactivator1α (PGC1α) expression, and memory differentiation. Underscoring clinical relevance, supplementation with the PI3kδ inhibitor idelalisib during CAR T-cell manufacturing improved persistence and long-term leukemia-free remissions in an immunocompetent murine model. Our study suggests that modulating the abnormal CLL T-cell metabolism can enhance the efficacy of autologous T-cell therapies.

Mutations found in AML such as DNMT3A, TET2 and ASXL1 can be found in the peripheral blood of healthy adults - a phenomenon termed clonal hematopoiesis (CH). These mutations are thought to represent the earliest genetic events in the evolution of AML. Genomic studies on samples acquired at diagnosis, remission, and at relapse have demonstrated significant stability of CH mutations following induction chemotherapy. Meanwhile, later mutations in genes such as NPM1 and FLT3, have been shown to contract at remission and in the case of FLT3 often are absent at relapse. We sought to understand how early CH mutations influence subsequent evolutionary trajectories throughout remission and relapse in response to induction chemotherapy. We assembled a retrospective cohort of patients diagnosed with de novo AML at our institution that underwent genomic sequencing at diagnosis, remission and/or relapse (total n=182 patients). FLT3 and NPM1 mutations were generally eliminated at complete remission but subsequently reemerged upon relapse, whereas DNMT3A, TET2 and ASXL1 mutations often persisted through remission. CH-related mutations exhibited distinct constellations of co-occurring genetic alterations, with NPM1 and FLT3 mutations enriched in DNMT3Amut AML, while CBL and SRSF2 mutations were enriched in TET2mut and ASXL1mut AML, respectively. In the case of NPM1 and FLT3 mutations, these differences vanished at the time of complete remission yet readily reemerged upon relapse, indicating the reproducible nature of these genetic interactions. Thus, CH-associated mutations that likely precede malignant transformation subsequently shape the evolutionary trajectories of AML through diagnosis, therapy, and relapse.