Fakih, Riad El

T cell fitness has emerged as a critical determinant of the efficacy and persistence of Chimeric Antigen Receptor (CAR)-T cell therapy. Defined by the capacity of T cells to proliferate, resist exhaustion, persist in vivo , and exert sustained effector functions, T cell fitness reflects the integration of a dynamic network of intrinsic and extrinsic regulatory mechanisms. In this review, we present a comprehensive synthesis of the molecular and cellular foundations underlying T cell fitness, emphasizing the influence of differentiation trajectories, signaling pathways, metabolic reprogramming, and epigenetic modifications. We further discuss the impact of patient-specific conditions such as age as well as disease biology, prior therapeutic exposures, and timing and quality of T cell collection, on the phenotypic and functional efficacy of CAR-T cell products. Beyond delineating these determinants, we highlight emerging strategies aimed at enhancing T cell fitness. Importantly, we propose T cell fitness as an integrated, multi-layered systems property emerging from the interaction between differentiation state, signaling architecture, metabolic–mitochondrial competence, epigenetic stability, and host-specific inflammatory and treatment-related pressures. We introduce a mechanistic framework that links these layers across the CAR-T therapeutic timeline from leukapheresis to post-infusion tumor engagement and outline how this framework can be operationalized into measurable parameters to guide patient stratification, manufacturing decisions, and rational therapeutic interventions.

Objectives: The aim of this systematic review is to investigate different diagnostic methods and the available treatment options for subcutaneous panniculitis-like T-cell lymphoma (SPTCL). Methods: We searched PubMed, Web of Science, SCOPUS, EBSCO, and CINAHL Plus for published case reports of SPTCL. From each record, we extracted data of the diagnostic methods, immunohistochemical profile, clinical characteristics, and the treatment approaches provided. Data were summarized and narratively synthesized to highlight the various diagnostic methods and treatment options of SPTCL. Results: Our literature search yielded 1293 unique citations. Following screening, nine articles reporting a total of 15 cases were included in this systematic review. All patients presented with subcutaneous nodules. Three of the 15 cases were initially misdiagnosed. The atypical lymphoid cells were positive for CD2, CD3, granzyme B, and TIA-1 and negative for CD1a, EBER, and CD20 in all the reported cases. The atypical lymphoid cells were positive for CD45RO in four out of seven cases, positive for CD56 in three out of 12 cases tested, while positive for CD5 and CD8 in the majority of cases. Therapy ranged from topical agents to immunosuppressive agents all the way to multiagent chemotherapy. Conclusion: SPTCL is a rare lymphoma. Diagnosis is highly dependent on the immunohistochemical stains added to histopathologic and radiologic findings. Therapy is dependent on the pace of the disease, with encouraging results obtained with single-agent cyclosporine.

AbstractSecondary acute myeloid leukemia (sAML) includes AML as a complication of an antecedent hematological disorder or a therapy‐related AML. Large registry‐based data identified sAML as an independent poor‐outcome type of AML post allogeneic hematopoietic cell transplantation (allo‐HCT). In our study, we tried to define factors affecting outcomes of sAML post allo‐HCT, and identify patients with sAML who may truly benefit from allo‐HCT. We retrospectively analyzed the data of 64 patients aged (14‐61 years) with sAML who received allo‐HCT between September 2010 and February 2018 at our institute. Most of the patients were transplanted from matched related donors (MRD; 54, 84.4%). Our results showed that poor‐risk cytogenetics were identified in 31 patients (48.4%), and their presence was an indicator of poor overall survival (OS) and disease‐free survival (DFS; P‐value = .009, and .004, respectively). The cumulative incidence of chronic graft‐versus‐host disease (cGVHD) was significantly lower in sAML patients with poor‐risk cytogenetics (P‐value = .003) resulting in a high risk of death without cGVHD in this group of patients (P‐value = .02). Besides, GVHD relapse‐free survival (GRFS) analysis showed that most of our studied patients experienced either relapse or debilitating grade II‐IV cGVHD in the first 2 years post allo‐HCT. We conclude that sAML patients with poor‐risk cytogenetics have a significantly lower DFS post allo‐HCT with a high risk of death without active cGVHD.

Hematopoietic cell transplant is a potentially curative procedure for many benign and malignant conditions. The efficacy of allogeneic transplant relies in part on the cytotoxicity of the conditioning regimen and the graft versus tumor effect mediated by alloreactive donor T cells; the same cells are also implicated in the development of graft versus host disease (GVHD). Selective identification and depletion of the T cells implicated in GVHD, while preserving the T cells responsible for graft versus tumor effect has been the focus of many research groups in the recent years. Here we briefly review the physiology of T cells in transplantation, and comment on a recent clinical trial published by Bleakly et al. using a novel way of graft engineered allograft via naïve T cell depletion.