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Viral infection induces potent cellular immunity and activated intracellular signaling, which may dictate the driver events involved in immune escape and clonal selection of virus-associated cancers, including Epstein-Barr virus (EBV)-positive lymphomas. Here, we thoroughly interrogated PD-L1/PD-L2 -involving somatic aberrations in 384 samples from various lymphoma subtypes using high-throughput sequencing, particularly focusing on virus-associated lymphomas. A high frequency of PD-L1/PD-L2 -involving genetic aberrations was observed in EBV-positive lymphomas [33 (22%) of 148 cases], including extranodal NK/T-cell lymphoma (ENKTL, 23%), aggressive NK-cell leukemia (57%), systemic EBV-positive T-cell lymphoproliferative disorder (17%) as well as EBV-positive diffuse large B-cell lymphoma (DLBCL, 19%) and peripheral T-cell lymphoma-not otherwise specified (15%). Predominantly causing a truncation of the 3′-untranslated region, these alterations represented the most prevalent somatic lesions in ENKTL. By contrast, the frequency was much lower in EBV-negative lymphomas regardless of histology type [12 (5%) of 236 cases]. Besides PD-L1/PD-L2 alterations, EBV-positive DLBCL exhibited a genetic profile distinct from EBV-negative one, characterized by frequent TET2 and DNMT3A mutations and the paucity of CD79B , MYD88 , CDKN2A , and FAS alterations. Our findings illustrate unique genetic features of EBV-associated lymphomas, also suggesting a potential role of detecting PD-L1/PD-L2 -involving lesions for these lymphomas to be effectively targeted by immune checkpoint blockade.

Chimeric antigen receptor (CAR) T cells targeting CD19 are a breakthrough treatment for relapsed, refractory B cell malignancies 1 – 5 . Despite impressive outcomes, relapse with CD19 − disease remains a challenge. We address this limitation through a first-in-human trial of bispecific anti-CD20, anti-CD19 (LV20.19) CAR T cells for relapsed, refractory B cell malignancies. Adult patients with B cell non-Hodgkin lymphoma or chronic lymphocytic leukemia were treated on a phase 1 dose escalation and expansion trial ( NCT03019055 ) to evaluate the safety of 4-1BB–CD3ζ LV20.19 CAR T cells and the feasibility of on-site manufacturing using the CliniMACS Prodigy system. CAR T cell doses ranged from 2.5 × 10 5 –2.5 × 10 6 cells per kg. Cell manufacturing was set at 14 d with the goal of infusing non-cryopreserved LV20.19 CAR T cells. The target dose of LV20.19 CAR T cells was met in all CAR-naive patients, and 22 patients received LV20.19 CAR T cells on protocol. In the absence of dose-limiting toxicity, a dose of 2.5 × 10 6 cells per kg was chosen for expansion. Grade 3–4 cytokine release syndrome occurred in one (5%) patient, and grade 3–4 neurotoxicity occurred in three (14%) patients. Eighteen (82%) patients achieved an overall response at day 28, 14 (64%) had a complete response, and 4 (18%) had a partial response. The overall response rate to the dose of 2.5 × 10 6 cells per kg with non-cryopreserved infusion ( n  = 12) was 100% (complete response, 92%; partial response, 8%). Notably, loss of the CD19 antigen was not seen in patients who relapsed or experienced treatment failure. In conclusion, on-site manufacturing and infusion of non-cryopreserved LV20.19 CAR T cells were feasible and therapeutically safe, showing low toxicity and high efficacy. Bispecific CARs may improve clinical responses by mitigating target antigen downregulation as a mechanism of relapse. A new bispecific CAR T cell product targeting the CD20 and CD19 antigens demonstrates an excellent safety profile and high clinical efficacy in patients with B cell non-Hodgkin lymphoma and chronic lymphocytic leukemia.

Sialic acids are negatively charged carbohydrates that cap the glycans of glycoproteins and glycolipids. Sialic acids are involved in various biological processes including cell–cell adhesion and immune recognition. In dendritic cells (DCs), the major antigen-presenting cells of the immune system, sialic acids emerge as important regulators of maturation and interaction with other lymphocytes including T cells. Many aspects of how sialic acids regulate DC functions are not well understood and tools and model systems to address these are limited. Here, we have established cultures of murine bone marrow-derived DCs (BMDCs) that lack sialic acid expression using a sialic acid-blocking mimetic Ac 5 3F ax Neu5Ac. Ac 5 3F ax Neu5Ac treatment potentiated BMDC activation via toll-like receptor (TLR) stimulation without affecting differentiation and viability. Sialic acid blockade further increased the capacity of BMDCs to induce antigen-specific CD8 + T cell proliferation. Transcriptome-wide gene expression analysis revealed that sialic acid mimetic treatment of BMDCs induces differential expression of genes involved in T cell activation, cell-adhesion, and cell–cell interactions. Subsequent cell clustering assays and single cell avidity measurements demonstrated that BMDCs with reduced sialylation form higher avidity interactions with CD8 + T cells. This increased avidity was detectable in the absence of antigens, but was especially pronounced in antigen-dependent interactions. Together, our data show that sialic acid blockade in BMDCs ameliorates maturation and enhances both cognate T cell receptor–MHC-dependent and independent T cell interactions that allow for more robust CD8 + T cell responses.

Loss of the PD-1 receptor promotes the development of T cell non-Hodgkin lymphomas by modulating oncogenic signalling pathways, and blocking these pathways reduces tumourigenesis. Checkpoint factor suppresses lymphoma PD-1 functions as an inhibitory receptor in the immune system and is a target of cancer immunotherapy. Jürgen Ruland and colleagues now show that PD-1 also functions as a tumour suppressor that is often lost in human T cell lymphomas. Experimentally, loss of PD-1 promotes the development of T cell non-Hodgkin lymphomas by modulating oncogenic signalling pathways. Blocking these pathways reduces tumorigenesis. These findings may have implications for T cell lymphoma therapies. T cell non-Hodgkin lymphomas are a heterogeneous group of highly aggressive malignancies with poor clinical outcomes 1 . T cell lymphomas originate from peripheral T cells and are frequently characterized by genetic gain-of-function variants in T cell receptor (TCR) signalling molecules 1 , 2 , 3 , 4 . Although these oncogenic alterations are thought to drive TCR pathways to induce chronic proliferation and cell survival programmes, it remains unclear whether T cells contain tumour suppressors that can counteract these events. Here we show that the acute enforcement of oncogenic TCR signalling in lymphocytes in a mouse model of human T cell lymphoma drives the strong expansion of these cells in vivo . However, this response is short-lived and robustly counteracted by cell-intrinsic mechanisms. A subsequent genome-wide in vivo screen using T cell-specific transposon mutagenesis identified PDCD1 , which encodes the inhibitory receptor programmed death-1 (PD-1), as a master gene that suppresses oncogenic T cell signalling. Mono- and bi-allelic deletions of PDCD1 are also recurrently observed in human T cell lymphomas with frequencies that can exceed 30%, indicating high clinical relevance. Mechanistically, the activity of PD-1 enhances levels of the tumour suppressor PTEN and attenuates signalling by the kinases AKT and PKC in pre-malignant cells. By contrast, a homo- or heterozygous deletion of PD-1 allows unrestricted T cell growth after an oncogenic insult and leads to the rapid development of highly aggressive lymphomas in vivo that are readily transplantable to recipients. Thus, the inhibitory PD-1 receptor is a potent haploinsufficient tumour suppressor in T cell lymphomas that is frequently altered in human disease. These findings extend the known physiological functions of PD-1 beyond the prevention of immunopathology after antigen-induced T cell activation, and have implications for T cell lymphoma therapies and for current strategies that target PD-1 in the broader context of immuno-oncology.

Autologous chimeric antigen receptor (CAR) T cell therapies targeting CD19 have high efficacy in large B cell lymphomas (LBCLs), but long-term remissions are observed in less than half of patients, and treatment-associated adverse events, such as immune effector cell-associated neurotoxicity syndrome (ICANS), are a clinical challenge. We performed single-cell RNA sequencing with capture-based cell identification on autologous axicabtagene ciloleucel (axi-cel) anti-CD19 CAR T cell infusion products to identify transcriptomic features associated with efficacy and toxicity in 24 patients with LBCL. Patients who achieved a complete response by positron emission tomography/computed tomography at their 3-month follow-up had three-fold higher frequencies of CD8 T cells expressing memory signatures than patients with partial response or progressive disease. Molecular response measured by cell-free DNA sequencing at day 7 after infusion was significantly associated with clinical response ( P = 0.008), and a signature of CD8 T cell exhaustion was associated ( q = 2.8 × 10 −149 ) with a poor molecular response. Furthermore, a rare cell population with monocyte-like transcriptional features was associated ( P = 0.0002) with high-grade ICANS. Our results suggest that heterogeneity in the cellular and molecular features of CAR T cell infusion products contributes to variation in efficacy and toxicity after axi-cel therapy in LBCL, and that day 7 molecular response might serve as an early predictor of CAR T cell efficacy. Single-cell transcriptomics reveals that the heterogeneity of anti-CD19 CAR T cell infusion products contributes to variability in clinical response, early molecular response and development of immune effector cell-associated neurotoxicity syndrome in patients with large B cell lymphomas.

Extranodal natural killer (NK)/T-cell lymphoma is an aggressive malignancy of putative NK-cell origin, with a minority deriving from the T-cell lineage. Pathologically, the malignancy occurs in two forms, extranodal NK/T-cell lymphoma, nasal type; and aggressive NK-cell leukaemia. Lymphoma occur most commonly (80%) in the nose and upper aerodigestive tract, less commonly (20%) in non-nasal areas (skin, gastrointestinal tract, testis, salivary gland), and rarely as disseminated disease with a leukemic phase. Genetic analysis showed mutations of genes involved in the JAK/STAT pathway, RNA assembly, epigenetic regulation, and tumor suppression. In initial clinical evaluation, positron emission tomography computed tomography, and quantification of plasma EBV DNA are mandatory as they are useful for response monitoring and prognostication. In stage I/II diseases, combined chemotherapy and radiotherapy (sequentially or concurrently) is the best approach. Conventional anthracycline-containing regimens are ineffective and should be replaced by non-anthracycline-containing regimens, preferably including L-asparaginase. Radiotherapy alone is associated with high systemic relapse rates and should be avoided. In stage III/IV diseases, non-anthracycline-regimens-containing L-asparaginase are the standard. In relapsed/refractory cases, blockade of the programmed death protein 1 has recently shown promising results with high response rates. In the era of effective non-anthracycline-containing regimens, autologous haematopoietic stem cell transplantation (HSCT) has not been shown to be beneficial. However, allogeneic HSCT may be considered for high-risk or advanced-stage patients in remission or relapsed/refractory patients responding to salvage therapy. Prognostic models taking into account presentation, interim, and end-of-treatment parameters are useful in triaging patients to different treatment strategies.

Most T cell receptor (TCR)Vβ chain-expressing T cell lymphomas (TCL) including those caused by Human T cell leukaemia virus type-1 (HTLV-1) have poor prognosis. We hypothesised that chimeric antigen receptor (CAR)-mediated targeting of the clonal, lymphoma-associated TCRβ chains would comprise an effective cell therapy for TCL that would minimally impact the physiological TCR repertoire. As proof of concept, we generated CAR constructs to target four TCRVβ subunits. Efficacy of the CAR constructs was tested using conventional T cells as effectors (CAR-T). Since invariant NKT (iNKT) cell do not incite acute graft-versus-host disease and are suitable for 'off-the-shelf' immunotherapy, we generated anti-TCRVβ CAR-iNKT cells. We show that anti-TCRVβ CAR-T cells selectively kill their cognate tumour targets while leaving >90% of the physiological TCR repertoire intact. CAR-iNKT cells inhibited the growth of TCL , and were also selectively active against malignant cells from Adult T cell leukaemia/lymphoma patients without activating expression of HTLV-1. Thus we provide proof-of-concept for effective and selective anti-TCRVβ CAR-T and -iNKT cell-based therapy of TCL with the latter providing the option for 'off-the-shelf' immunotherapy.

Introducing chimeric antigen receptors into the endogenous T-cell receptor locus reduces tonic signalling, averts accelerated T-cell differentiation and delays T-cell exhaustion, leading to enhanced function and anti-tumour efficacy compared to random integrations. Making a CAR drive tumour rejection Using T cells transduced with synthetic chimeric antigen receptors (CARs) is a promising strategy for treating certain types of cancer. Here Michel Sadelain and colleagues provide evidence in a mouse tumour model that knocking the CAR into the endogenous T-cell receptor α constant locus reduces tonic signalling, avoids accelerated T-cell differentiation, and delays T-cell exhaustion. This results in enhanced function and anti-tumour efficacy compared with random integrations. Chimeric antigen receptors (CARs) are synthetic receptors that redirect and reprogram T cells to mediate tumour rejection 1 . The most successful CARs used to date are those targeting CD19 (ref. 2 ), which offer the prospect of complete remission in patients with chemorefractory or relapsed B-cell malignancies 3 . CARs are typically transduced into the T cells of a patient using γ-retroviral 4 vectors or other randomly integrating vectors 5 , which may result in clonal expansion, oncogenic transformation, variegated transgene expression and transcriptional silencing 6 , 7 , 8 . Recent advances in genome editing enable efficient sequence-specific interventions in human cells 9 , 10 , including targeted gene delivery to the CCR5 and AAVS1 loci 11 , 12 . Here we show that directing a CD19-specific CAR to the T-cell receptor α constant ( TRAC ) locus not only results in uniform CAR expression in human peripheral blood T cells, but also enhances T-cell potency, with edited cells vastly outperforming conventionally generated CAR T cells in a mouse model of acute lymphoblastic leukaemia. We further demonstrate that targeting the CAR to the TRAC locus averts tonic CAR signalling and establishes effective internalization and re-expression of the CAR following single or repeated exposure to antigen, delaying effector T-cell differentiation and exhaustion. These findings uncover facets of CAR immunobiology and underscore the potential of CRISPR/Cas9 genome editing to advance immunotherapies.

Pule and colleagues identify the TCR β-chain constant region as a new target for chimeric antigen receptor (CAR) T cells in treatment of T cell cancers while potentially preserving a healthy T cell repertoire. They demonstrate that anti-TCRB1 CAR T cells eliminate cancerous TCRB1 + T cells while sparing nearly one-third of normal TCRB2 + T cells. Mature T cell cancers are typically aggressive, treatment resistant and associated with poor prognosis. Clinical application of immunotherapeutic approaches has been limited by a lack of target antigens that discriminate malignant from healthy (normal) T cells. Unlike B cell depletion, pan–T cell aplasia is prohibitively toxic. We report a new targeting strategy based on the mutually exclusive expression of T cell receptor β-chain constant domains 1 and 2 (TRBC1 and TRBC2). We identify an antibody with unique TRBC1 specificity and use it to demonstrate that normal and virus-specific T cell populations contain both TRBC1 + and TRBC2 + compartments, whereas malignancies are restricted to only one. As proof of concept for anti-TRBC immunotherapy, we developed anti-TRBC1 chimeric antigen receptor (CAR) T cells, which recognized and killed normal and malignant TRBC1 + , but not TRBC2 + , T cells in vitro and in a disseminated mouse model of leukemia. Unlike nonselective approaches targeting the entire T cell population, TRBC-targeted immunotherapy could eradicate a T cell malignancy while preserving sufficient normal T cells to maintain cellular immunity.