The 2017 European LeukemiaNet (ELN 2017) guidelines for the diagnosis and management of acute myeloid leukemia (AML) have become fundamental guidelines to assess the prognosis and postremission therapy of patients. However, they have been retrospectively validated in few studies with patients included in different treatment protocols. We analyzed 861 patients included in the Cooperativo Para el Estudio y Tratamiento de las Leucemias Agudas y Mielodisplasias-12 risk-adapted protocol, which indicates cytarabine-based consolidation for patients allocated to the ELN 2017 favorable-risk group, whereas it recommends allogeneic stem cell transplantation (alloSCT) as a postremission strategy for the ELN 2017 intermediate- and adverse-risk groups. We retrospectively classified patients according to the ELN 2017, with 327 (48%), 109 (16%), and 245 (36%) patients allocated to the favorable-, intermediate-, and adverse-risk group, respectively. The 2- and 5-year overall survival (OS) rates were 77% and 70% for favorable-risk patients, 52% and 46% for intermediate-risk patients, and 33% and 23% for adverse-risk patients, respectively. Furthermore, we identified a subgroup of patients within the adverse group (inv(3)/t(3;3), complex karyotype, and/or TP53 mutation/17p abnormality) with a particularly poor outcome, with a 2-year OS of 15%. Our study validates the ELN 2017 risk stratification in a large cohort of patients treated with an ELN-2017 risk-adapted protocol based on alloSCT after remission for nonfavorable ELN subgroups and identifies a genetic subset with a very poor outcome that warrants investigation of novel strategies.

T-cell large granular lymphocytic leukemia (T-LGLL) and chronic lymphoproliferative disorder of natural killer (NK) cells are two infrequent diseases characterized by clonal expansions of cytotoxic T lymphocytes and NK cells, respectively. Somatic mutations of STAT3 are involved in the pathogenesis of these entities. We describe the clinicobiological features, mutational status of STAT3/STAT5B, treatment and outcome of 131 patients. Neutropenia was the most frequent finding at diagnosis, followed by anemia. Concurrent hematological disorders were diagnosed in 37% of patients and autoimmune conditions and solid tumors in 17% and 15%, respectively. All patients who needed treatment belonged to the CD8⁺CD57⁺ group. Remarkably, patients included in the CD4⁺ group had a higher association with solid tumors (p = 0.037). STAT3 mutations were found in 17% of patients, mainly Y640F and D661Y mutations. Patients carrying STAT3 mutations more frequently presented with anemia, neutropenia, high LDH, high large granular lymphocyte counts and need for treatment (p = 0.0037). Methotrexate was the most frequently used agent (72% of cases). The overall response rate to all treatments was 50%. The 10-year overall survival of this series was 78%, with no differences according to the mutational status of STAT3. We compared the survival of these patients with the general Spanish population and no differences were found, confirming the indolent nature of these hematological malignancies. Our study further extends findings documented by others on the clinical behavior of the disease and the impact of STAT3, and for the first time analyzes survival compared to a matched general Spanish population.

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is a rare, aggressive subtype of diffuse large B-cell lymphoma characterized by a profoundly immunosuppressive tumor microenvironment. PD-L1 overexpression by tumor cells is a recognized immune escape mechanism and may underlie resistance to cellular therapies, including CAR T-cell therapy. We report a case of a 29-year-old woman with refractory stage IV-B THRLBCL treated with anti-CD19 CAR T-cell therapy (varnimcabtagene autoleucel), who achieved an initial response (day +28) but experienced disease progression by day +100 despite robust CAR T-cell expansion. Peripheral blood analysis revealed persistent absolute B-cell aplasia, while bone marrow biopsy confirmed CD19-positive disease. Comparative immunohistochemistry demonstrated markedly increased PD-L1 expression in post-CAR T-cell samples, suggesting adaptive immune resistance via PD-1/PD-L1-mediated CAR T-cell inhibition. Nivolumab was initiated at month +4 to overcome this checkpoint-mediated resistance. Notably, a complete metabolic response was documented on PET/CT after four doses of nivolumab (month +6). The patient remains in sustained remission, with persistent B-cell aplasia, four years post-intervention. This case provides clinical and pathological evidence supporting the use of immune checkpoint blockade to rescue CAR T-cell efficacy, highlighting the potential of this synergistic approach in THRLBCL and possibly other B-cell malignancies exhibiting similar immune evasion.

Although first-line immunotherapy achieves remission in most patients with follicular lymphoma (FL), improved biomarkers and therapeutic strategies are required to identify and manage those who relapse. We investigated the immune microenvironment at diagnosis in uniformly treated FL patients with extended follow-up (>11 years), comparing relapsed and relapse-free cases. Transcriptomic profiling revealed enrichment of inflammatory response pathways in relapsed patients, including cytokine overexpression and upregulation of CD70, a molecule implicated in immune activation and inflammation. Multiplex immunofluorescence confirmed CD70 overexpression at diagnosis in tumor cells as well as in CD8⁺ and CD4⁺ T follicular helper (TFH) cells, correlating with inferior progression-free survival. Functional studies demonstrated that CD70⁺ tumor cells were more proliferative and induced CD70 expression in T cells, suggesting a feed-forward loop sustaining immune activation. To target these cells and enhance current CAR-T approaches, we engineered dual CD19-CD70 chimeric antigen receptor (CAR) T cells by co-transducing the CD19-CAR-T ARI-0001 with a CD27-based anti-CD70 CAR. Dual CAR-T cells exhibited enhanced in vitro cytotoxicity against patient-derived spheroids of FL, diffuse large B-cell lymphoma, and mantle cell lymphoma. In FL xenograft models, dual CAR-T treatment achieved superior disease control compared to monotargeted CAR-T cells, inducing complete tumor clearance in spleen and bone marrow. Collectively, these findings provide strong preclinical rationale for the clinical development of CD19-CD70 dual CAR-T therapy to improve outcomes in high-risk FL and potentially other B-cell non-Hodgkin lymphomas.