Despite unprecedented efficacy, 1 the use of axicabtagene ciloleucel (axi-cel) for the treatment of patients with relapsed or refractory large B-cell lymphoma (LBCL) remains associated with acute toxicity, such as grade $3 cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), occurring in 11% and 32% of patients, respectively. 2 Analysis of 44 different analytes in the serum of patients with relapsed or refractory LBCL treated with axi-cel showed that an increase in IL-6 or IL-1 may be associated with such toxicity. 3 However, in 2 murine models, whereas IL-6 blockade (typically achieved in clinical practice with the use of tocilizumab) prevented CRS only, only IL-1 blockade prevented both CRS and/or ICANS. 4,5 IL-1 blockade can be clinically achieved with the use of anakinra, an IL-1 receptor antagonist, currently approved by the US Food and Drug Administration for the treatment of patients with rheumatoid arthritis and neonatal-onset multisystem inflammatory disease. 6,7 Anakinra is also used off label for the treatment of secondary hemophagocytic lymphohistiocytosis (HLH), a condition in the spectrum of CRS potentially associated with chimeric antigen receptor (CAR) T-cell therapy. 8,9 Data regarding the clinical use of anakinra for the mitigation of axi-cel-associated toxicity have not been published.

Follicular lymphoma (FL) is a B-cell malignancy with a complex tumor microenvironment that is rich in nonmalignant immune cells. We applied single-cell RNA sequencing to characterize the diverse tumor and immune cell populations of FL and identified major phenotypic subsets of FL T cells, including a cytotoxic CD4 T-cell population. We characterized four major FL subtypes with differential representation or relative depletion of distinct T-cell subsets. By integrating exome sequencing, we observed that somatic mutations are associated with, but not definitive for, reduced MHC expression on FL cells. In turn, expression of MHCII genes by FL cells was associated with significant differences in the proportions and targetable immunophenotypic characteristics of T cells. This provides a classification framework of the FL microenvironment in association with FL genotypes and MHC expression, and informs different potential immunotherapeutic strategies based upon tumor cell MHCII expression. Significance: We have characterized the FL-infiltrating T cells, identified cytotoxic CD4 T cells as an important component that is associated with tumor cell–intrinsic characteristics, and identified sets of targetable immune checkpoints on T cells that differed from FLs with normal versus low MHC expression. See related commentary by Melnick, p. 374. This article is highlighted in the In This Issue feature, p. 369

Summary: The ultimate cause of death for most patients with newly diagnosed chronic lymphocytic leukaemia (CLL) and its relationship to co‐morbid health conditions is poorly defined. We conducted a prospective cohort study that systematically followed 1143 patients diagnosed with CLL between June 2002 and November 2014. Comorbid health conditions at the time of CLL diagnosis and their relationship to survival and cause of death were evaluated. Collectively, 1061 (93%) patients had at least one co‐morbid health condition at the time of CLL diagnosis (median number 3). Despite this, 89% of patients had a low‐intermediate Charlson Comorbidity Index score (CCI) at diagnosis. After a median follow‐up of 6 years, 225 patients have died. Death was due to CLL progression in 85 (46%) patients, infection in 14 (8%) patients, other cancer in 35 (19%) patients and comorbid health conditions in 50 (27%) patients. Higher CCI score and a greater number of major comorbid health conditions at the time of CLL diagnosis was associated with shorter non‐CLL specific survival, but not with shorter CLL‐specific survival on multivariate analysis. In conclusion, CLL and CLL‐related complications (infections and second cancers) are the overwhelming cause of death in patients with CLL, regardless of CCI score and number of comorbid health conditions at diagnosis.

Chimeric antigen receptor-modified (CAR) T cells targeting CD19 have revolutionized the treatment of relapsed or refractory aggressive B-cell lymphomas, and their use has increased the cure rate for these cancers from 10 to 40%. Two second-generation anti-CD19 CAR T-cell products, axicabtagene ciloleucel and tisagenlecleucel, have been approved for use in patients, and the approval of a third product, lisocabtagene maraleucel, is expected in 2020. The commercial availability of the first two products has facilitated the development of real-world experience in treating relapsed or refractory aggressive B-cell lymphomas, shed light on anti-CD19 CAR T-cell products' feasibility in trial-ineligible patients, and raised the need for strategies to mitigate the adverse effects associated with anti-CD19 CAR T-cell therapy, such as cytokine release syndrome, neurotoxicity, and cytopenia. In addition, promising clinical data supporting the use of anti-CD19 CAR T-cell therapy in patients with indolent B-cell lymphomas or chronic lymphocytic leukemia have recently become available, breaking the paradigm that these conditions are not curable. Multiple clinical CAR T-cell therapy-based trials are ongoing. These include studies comparing CAR T-cell therapy to autologous stem cell transplantation or investigating their use at earlier stages of disease, novel combinations, and novel constructs. Here we provide a thorough review on the use of the anti-CD19 CAR T-cell products axicabtagene ciloleucel, tisagenlecleucel and lisocabtagene maraleucel in patients with indolent or aggressive B-cell lymphoma or with chronic lymphocytic leukemia, and present novel CAR T cell-based approaches currently under investigation in these disease settings.

The in vivo persistence of adoptively transferred T cells is predictive of antitumor response. Identifying functional properties of infused T cells that lead to in vivo persistence and tumor eradication has remained elusive. We profiled CD19-specific chimeric antigen receptor (CAR) T cells as the infusion products used to treat large B cell lymphomas using high-throughput single-cell technologies based on time-lapse imaging microscopy in nanowell grids (TIMING), which integrates killing, cytokine secretion, and transcriptional profiling. Our results show that the directional migration of CD19-specific CAR T cells is correlated with multifunctionality. We showed that CD2 on T cells is associated with directional migration and that the interaction between CD2 on T cells and CD58 on lymphoma cells accelerates killing and serial killing. Consistent with this, we observed that elevated CD58 expression on pretreatment tumor samples in patients with relapsed or refractory large B cell lymphomas treated with CD19-specific CAR T cell therapy was associated with complete clinical response and survival. These results highlight the importance of studying dynamic T cell–tumor cell interactions in identifying optimal antitumor responses.