Adoptively transferred CD19 chimeric antigen receptor (CAR) T-cells have led to impressive clinical outcomes in B-cell malignancies. Beyond induction of remission, the persistence of CAR-T cells is required to prevent relapse and provide long-term disease control. To improve CAR-T cell function and persistence, we developed a composite costimulatory domain of a B-cell signaling moiety, CD79A/CD40, to induce a nuclear translocating signal, NF-κB, to synergize with other T-cell signals and improve CAR-T cell function. CD79A/CD40 incorporating CD19CAR-T cells (CD19.79a.40z) exhibited higher NF-κB and p38 activity upon CD19 antigen exposure compared with the CD28 or 4-1BB incorporating CD19CAR-T cells (CD19.28z and CD19.BBz). Notably, we found that CD19.79a.40z CAR-T cells continued to suppress CD19⁺ target cells throughout the co-culture assay, whereas a tendency for tumor growth was observed with CD19.28z CAR-T cells. Moreover, CD19.79a.40z CAR-T cells exhibited robust T-cell proliferation after culturing with CD19⁺ target cells regardless of exogenous interleukin-2. In terms of in vivo efficiency, CD19.79a.40z demonstrated superior anti-tumor activity and in vivo CAR-T cell proliferation compared with CD19.28z and CD19.BBz CD19CAR-T cells in Raji-inoculated mice. Taken together, our data demonstrate that the CD79A/CD40 costimulatory domain endows CAR-T cells with enhanced proliferative capacity and improved anti-tumor efficacy in a murine model.

To determine the predictors for 30-day all-cause mortality in patients with febrile neutropenia (FN) and develop a prediction score. The electronic medical records of patients undergoing chemotherapy with FN between 2018 and 2019 were reviewed. Multivariate logistic regression was performed to identify factors associated with 30-day all-cause mortality to develop a parsimonious model. A prediction score was developed from the model's coefficients of each predictor. There were 273 FN episodes in 153 patients. The overall mortality rate was 12.5%. Pre-existing cardiovascular disease (OR 22.45), alteration of consciousness on admission (OR 18.50), anemia (OR 4.33), acute kidney injury (AKI) (OR 13.15), causative pathogen identified (OR 8.68), intensive care unit admission (OR 0.13), septic shock (OR 18.72), and the need for mechanical ventilation (OR 22.65) were associated with mortality. After exploring confounding effects between factors, septic shock, anemia, AKI, and the need for mechanical ventilation were selected to develop the prediction score which provided good sensitivity (87.88%) and specificity (90.91%) with an area under the ROC curve of 0.8939. Septic shock, anemia, AKI, and the need for mechanical ventilation were associated with FN mortality. Our prediction score is effective in discriminating high and low-risk patients for mortality.

CD19 chimeric antigen receptor T (CD19CAR-T) cells have achieved promising outcomes in relapsed/refractory B cell malignancies. However, recurrences occur due to the loss of CAR-T cell persistence. We developed dual T/B cell co-stimulatory molecules (CD28 and CD40) in CAR-T cells to enhance intense tumoricidal activity and persistence. CD19.28.40z CAR-T cells promoted pNF-κB and pRelB downstream signaling while diminishing NFAT signaling upon antigen exposure. CD19.28.40z CAR-T cells demonstrated greater proliferation, which translated into effective anti-tumor cytotoxicity in long-term co-culture assay. Repetitive weekly antigen stimulation unveiled continuous CAR-T cell expansion while preserving central memory T cell subset and lower expression of exhaustion phenotypes. The intrinsic genes underlying CD19.28.40z CAR-T cell responses were compared with conventional CARs and demonstrated the up-regulated genes associated with T cell proliferation and memory as well as down-regulated genes related to apoptosis, exhaustion, and glycolysis pathway. Enrichment of genes toward T cell stemness, particularly SELL, IL-7r, TCF7, and KLF2, was observed. Effective and continuing anti-tumor cytotoxicity in vivo was exhibited in both B cell lymphoblastic leukemia and B cell non-Hodgkin lymphoma xenograft models while demonstrating persistent T cell memory signatures. The functional enhancement of CD37.28.40z CAR-T cell activities against CD37⁺ tumor cells was further validated. The modification of dual T/B cell signaling molecules remarkably maximized the efficacy of CAR-T cell therapy.

Despite the remarkable initial efficacy of CD19 chimeric Ag receptor T (CAR-T) cell therapy, a high incidence of relapse has been observed. To further increase treatment efficacy and reduce the rate of escape of Ag-negative cells, we need to develop CAR-T cells that target other Ags. Given its restricted expression pattern, CD37 was considered a preferred novel target for immunotherapy in hematopoietic malignancies. Therefore, we designed a CD37-targeting CAR-T (CD37CAR-T) using the single-chain variable fragment of a humanized anti-CD37 Ab, transmembrane and intracellular domains of CD28, and CD3ζ signaling domains. High levels of CD37 expression were confirmed in B cells from human peripheral blood and bone marrow B cell precursors at late developmental stages; by contrast, more limited expression of CD37 was observed in early precursor B cells. Furthermore, we found that human CD37CAR-T cells with longer spacer lengths exhibited high gene transduction efficacy but reduced capacity to proliferate; this may be due to overactivation and fratricide. Spacer length optimization resulted in a modest transduction efficiency together with robust capacity to proliferate. CD37CAR-T cells with optimized spacer length efficiently targeted various CD37⁺ human tumor cell lines but had no impact on normal leukocytes both in vitro and in vivo. CD37CAR-T cells effectively eradicated Raji cells in xenograft model. Collectively, these results suggested that spacer-optimized CD37CAR-T cells could target CD37-high neoplastic B cells both in vitro and in vivo, with only limited interactions with their normal leukocyte lineages, thereby providing an additional promising therapeutic intervention for patients with B cell malignancies. Key Points Novel anti–CD37CAR-T cells were developed to target another B cell Ag. Shorter spacer length CAR mediated the attenuated signaling rather than longer spacer CAR. Optimizing the spacer length minimized fratricide to maintain the antitumor effect.

CD19 chimeric antigen receptor (CAR) T-cells have demonstrated remarkable outcomes in B-cell malignancies. Recently, the novel CD19CAR-T cells incorporated with B-cell costimulatory molecules of CD79A/CD40 demonstrated superior antitumor activity in the B-cell lymphoma model compared with CD28 or 4-1BB. Here, we investigated the intrinsic transcriptional gene underlying the functional advantage of CD19.79A.40z CAR-T cells following CD19 antigen exposure using transcriptome analysis compared to CD28 or 4-1BB. Notably, CD19.79A.40z CAR-T cells up-regulated genes involved in T-cell activation, T-cell proliferation, and NF-κB signaling, whereas down-regulated genes associated with T-cell exhaustion and apoptosis. Interestingly, CD19.79A.40z CAR- and CD19.BBz CAR-T cells were enriched in almost similar pathways. Furthermore, gene set enrichment analysis demonstrated the enrichment of genes, which were previously identified to correlate with T-cell proliferation, interferon signaling pathway, and naïve and memory T-cell signatures, and down-regulated T-cell exhaustion genes in CD79A/CD40, compared with the T-cell costimulatory domain. The CD19.79A.40z CAR-T cells also up-regulated genes related to glycolysis and fatty acid metabolism, which are necessary to drive T-cell proliferation and differentiation compared with conventional CD19CAR-T cells. Our study provides a comprehensive insight into the understanding of gene signatures that potentiates the superior antitumor functions by CD19CAR-T cells incorporated with the CD79A/CD40 costimulatory domain.