Corticosteroid therapy is the mainstay of immune effector cell-associated neurotoxicity syndrome (ICANS) management, although its use has been associated with worse overall survival (OS) and progression-free survival (PFS) after chimeric antigen receptor T-cell (CAR-T cell) therapy. Many options are being investigated for prophylaxis and management. Accumulating evidence supports the use of intrathecal (IT) chemotherapy for the management of high-grade ICANS. Here, we describe a case of a patient with stage IV Primary mediastinal B-cell lymphoma (PMBCL) successfully treated with IT methotrexate, cytarabine, and dexamethasone as first-line therapy for CD19 CAR-T cell-associated grade IV ICANS. The stable and rapid resolution of ICANS to grade 0 allowed us to discontinue systemic corticosteroid use, avoiding CAR-T cells ablation and ensuring preservation of CAR-T cell function. The described patient achieved a complete radiologic and clinical response to CD19 CAR-T cell therapy and remains disease-free after 9 months. This case demonstrates a promising example of how IT chemotherapy could be used as first-line treatment for the management of high-grade ICANS.

UNASSIGNED: Multiple targets of chimeric antigen receptor T cells (CAR-T cells) are shared expressed by tumor cells and T cells, these self-antigens may stimulate CAR-T cells continuously during the expansion. Persistent exposure to antigens is considered to cause metabolic reprogramming of T cells and the metabolic profiling is critical in determining the cell fate and effector function of CAR-T cells. However, whether the stimulation of self-antigens during CAR-T cell generation could remodel the metabolic profiling is unclear. In this study, we aim to investigate the metabolic characteristics of CD26 CAR-T cells, which expressed CD26 antigens themselves.
UNASSIGNED: The mitochondrial biogenesis of CD26 and CD19 CAR-T cells during expansion was evaluated by the mitochondrial content, mitochondrial DNA copy numbers and genes involved in mitochondrial regulation. The metabolic profiling was investigated by the ATP production, mitochondrial quality and the expression of metabolism-related genes. Furthermore, we assessed the phenotypes of CAR-T cells through memory-related markers.
UNASSIGNED: We reported that CD26 CAR-T cells had elevated mitochondrial biogenesis, ATP production and oxidative phosphorylation at early expansion stage. However, the mitochondrial biogenesis, mitochondrial quality, oxidative phosphorylation and glycolytic activity were all weakened at later expansion stage. On the contrary, CD19 CAR-T cells did not exhibit such characteristics.
UNASSIGNED: CD26 CAR-T cells showed distinctive metabolic profiling during expansion that was extremely unfavorable to cell persistence and function. These findings may provide new insights for the optimization of CD26 CAR-T cells in terms of metabolism.

CAR-T cells present a highly effective therapeutic option for several malignant diseases, based on their ability to recognize the selected tumor surface marker in an MHC-independent manner. This triggers cell activation and cytokine production, resulting in the killing of the cancerous cell presenting markers recognized by the chimeric antigen receptor. CAR-T cells are highly potent serial killers that may cause serious side effects, so their activity needs to be carefully controlled. Here we designed a system to control the proliferation and activation state of CARs based on downstream NFAT transcription factors, whose activity can be regulated via chemically induced heterodimerization systems. Chemical regulators were used to either transiently trigger engineered T cell proliferation or suppress CAR-mediated activation when desired or to enhance activation of CAR-T cells upon engagement of cancer cells, shown also in vivo. Additionally, an efficient sensor to monitor activated CD19 CAR-T cells in vivo was introduced. This implementation in CAR-T cell regulation offers an efficient way for on-demand external control of CAR-T cell activity to improve their safety.

Objective: To establish a cytokine release syndrome (CRS) mouse model related to CAR-T cell therapy and provide a research model for the clinical phenomena. Methods: CAR-T cells targeting human CD19 molecule were constructed by molecular cloning and lentiviral transfection. Flow cytometry (FACS) was used to detect the transfection efficiency of CAR-T cells. The tumor-killing efficiency of CAR-T cells was detected by ELISA and flow cytometry. The CAR-T cells were injected into the tumor-bearing SCID/Beige mice through tail vein, and divided into phosphate buffered solution (PBS) group, low-burden group (1×10(5) Raji-Luc2 cells) and high-burden group (5×10(5) Raji-Luc2 cells). The tumor treatment effect was detected by animal in vivo imaging. Serum levels of cytokines including human IFN-γ, human IL-2, mouse IL-6, and mouse GM-CSF were measured by ELISA. The health status of the mice was evaluated by pathological examination. Results: The health scores of T cell group and T cell+ OKT-3 group were (1.15±0.08) and (2.90±0.15), respectively, after the injection of human T cell and T cell + OKT-3 antibody through tail vein, and the difference was statistically significant (P<0.001). The serum levels of human IL-2, human IFN-γ, human IL-15, mouse IL-6 and mouse GM-CSF in T cell+ OKT-3 group were (1 064.00±50.14), (1 285.00±193.90), (202.4±18.76), (1 478.00±289.20) and (350.70±42.27) pg/ml, respectively, higher than (22.67±6.36), (23.67±3.71), (44.33±14.45), (147.30±36.20), (138.00±22.74) pg/ml in T cell group (P<0.05). OKT-3 combined with human T cells caused a rapid increase in serum levels of human IL-2, human IFN-γ, mouse IL-6 and mouse GM-CSF, accompanied by an increase in body temperature and weight loss. CD19-targeting CAR-T cells were successfully constructed, and the positive rate of CAR-T cells was >30% detected by flow cytometry. ELISA results showed that in the presence of CD19 antigen, IL-2 and IFN-γ secreted by CAR-T19 cells co-incubated with Raji and Nalm were (561.00±37.07), (680.30±71.27), (369±25.71) and (523.00±26.31) pg/ml, respectively, higher than (55.00±20.53) and (64.00±7.55) pg/ml in the co-incubated with K562 group (P<0.001). Activated CAR-T19 cells were reinjected through the tail vein on the seventh day after tumor formation. Imaging experiments in mice showed that on the thirteenth day after tumor formation, the fluorescence intensities of tumors in the low-burden and high-burden groups were lower than on the seventh day of tumor inoculation, and the fluorescence intensity of tumors in the high-burden group decreased from 144.00±24.69 to 5.02±2.35 (P=0.005). The fluorescence intensity of low burden group decreased from 58.47±9.36 to 3.48±1.67 (P=0.004). The serum levels of T cell activation related cytokines IL-2, IL-15 and IFN-γ increased rapidly, and the secretion of monocyte related cytokines IL-16 and GM-CSF increased, accompanied by the typical characteristics of CRS such as increased body temperature and weight loss at 72 hours after injection of CAR-T19 cells. Conclusions: CAR-T cells targeting CD19 molecule are successfully constructed, and CRS phenomenon is verified in tumor-bearing mice by CAR-T cell re-infusion, providing an animal model for the mechanism of CAR-T treatment-related CRS and CRS prevention strategies.
目的： 建立嵌合抗原受体T(CAR-T)细胞治疗相关细胞因子释放综合征(CRS)的小鼠模型。 方法： 通过分子克隆及慢病毒转染技术，构建靶向人CD19分子的CAR-T细胞，采用流式细胞术检测CAR-T细胞转染效率，酶联免疫吸附试验(ELISA)法及流式细胞术检测CAR-T细胞特异性杀伤靶细胞的能力。通过尾静脉注射CAR-T细胞至荷瘤重症联合免疫缺陷裸鼠体内，小鼠分为磷酸缓冲液组、低负荷组(注射1×10(5)个人淋巴瘤细胞Raji-Luc2细胞)和高负荷组(注射5×10(5)个Raji-Luc2细胞)。采用动物活体成像法检测肿瘤治疗效果，ELISA法检测小鼠血清中细胞因子人白细胞介素2(IL-2)、人γ-干扰素(IFN-γ)、鼠IL-6、鼠粒细胞-巨噬细胞集落刺激因子(GM-CSF)的水平。 结果： 经尾静脉注射人T细胞和T细胞+OKT-3抗体后，T细胞组和T细胞+OKT-3组小鼠的健康得分分别为(1.15±0.08)分和(2.90±0.15)分，差异有统计学意义(P<0.001)。T细胞+OKT-3组小鼠血清中人IL-2、人IFN-γ、人IL-15、鼠IL-6、鼠GM-CSF水平分别为(1 064.00±50.14)、(1 285.00±193.90)、(202.4±18.76)、(1 478.00±289.20)和(350.70±42.27)pg/ml，均高于T细胞组[分别为(22.67±6.36)、(23.67±3.71)、(44.33±14.45)、(147.30±36.20)和(138.00±22.74)pg/ml，均P<0.05]；OKT-3联合人T细胞引起小鼠血清中细胞因子人IL-2、人IFN-γ、鼠IL-6、鼠GM-CSF水平迅速升高，并伴有体温升高及体重下降。成功构建靶向CD19分子的CAR-T细胞，流式细胞术检测CAR-T细胞阳性率>30%。ELISA结果显示，在CD19抗原存在时，CAR-T19细胞与Raji、Nalm-6共孵育组细胞分泌IL-2和IFN-γ的水平分别为(561.00±37.07)、(680.30±71.27)、(369.00±25.71)和(523.00±26.31)pg/ml，均高于与K562共孵育组[分别为(55.00±20.53)和(64.00±7.55)pg/ml，均P<0.001]。小鼠成像实验显示，小鼠成瘤后第7天经尾静脉回输活化后的CAR-T19细胞，成瘤第13天，低负荷和高负荷组小鼠肿瘤荧光强度均低于接种肿瘤的第7天，高负荷组肿瘤荧光强度由144.00±24.69减少至5.02±2.35(P＝0.005)，低负荷组肿瘤荧光强度由58.47±9.36减少至3.48±1.67(P＝0.004)。荷瘤小鼠注射CAR-T19细胞72 h后，血清中T细胞活化相关细胞因子人IL-2、人IL-15、人IFN-γ水平迅速增高，单核细胞相关因子鼠IL-16、鼠GM-CSF分泌增加，同时伴随有体温升高和体重降低等CRS典型特征。 结论： 体外成功构建靶向CD19分子的CAR-T细胞，通过CAR-T细胞回输治疗验证了小鼠体内CRS现象的发生，为CAR-T细胞治疗相关CRS的发生机制及CRS预防策略提供了动物模型参考。.

In recent years, adoptive cell therapy of immune effector cells, such as chimeric antigen receptor-T (CAR-T) cells, natural killer (NK) cells, and epitope-specific cytotoxic T lymphocyte (CTL) cells have been employed in clinical trials. In addition, CD19 CAR-T cells have been approved by the FDA for treatment of non-Hodgkin lymphoma and diffuse large B-cell lymphoma. In this context, it is vital to detect cellular cytotoxicity and monitor the quality of ex vivo expanded immune cells before product release and patient infusion. Target cells could proliferate in parallel with effector cells during the cytotoxicity assay, making it difficult to estimate the death ratio using conventional approaches. Meanwhile, non-specific dyes or non-homogeneous biomarkers for target cells may interfere with the final readout post addition of effector cells. Here, we modified a component of the coincubation medium to suppress the spontaneous release of bis(acetoxymethyl)2,2\':6\',2″-terpyridine-6,6″-dicarboxylate and sustained the window at a stable range (~70%). Further, the optimized Eu-TDA method presented reliable outcomes compared with lactate dehydrogenase detection and was compatible with cytotoxicity tests for NK cells and specific CTLs. Finally, the reported assay can accurately detect death of target cells depending on the amount of hydrophilic complex and can be reliably applied in quality control and cell activity evaluation tests on co-suspended effector and target cells. SUMMARY: A medium component for cellular coincubations (and associated protocols) have been optimized and validated for cytotoxicity assays, which can reliably evaluate the potency of engineered CD19 CAR-T cells, NK cells, and specific CTLs. In particular, the reported method can be applied widely in routine assays for bi-suspended effector and target cells with a stable window.

Chimeric receptor antigen (CAR) T cells are an innovative cellular immunotherapeutic approach that involves genetic modification of T cells to express CAR targeting tumor antigen. Prior to the development of CAR-T, the only potential cure for patients with relapsed or refractory (RR) acute lymphoblastic leukemia (ALL) was allogeneic hematopoietic stem cell transplantation (HSCT). Several CAR-T cell products have been studied in prospective clinical trials which ultimately have resulted in the approval of one anti-CD19 CAR-T cell product in pediatric RR ALL: tisagenlecleucel (CD3ζ and 41BB). While some patients achieve durable responses with CAR-T, lack of response and relapse remains clinical challenges. Reasons for sub-optimal response include lack of CAR-T cell persistence and target antigen down-regulation. Future CARs are under development to improve long-term persistence and to be able to overcome resistance mechanisms associated with the disease and the hostile tumor microenvironment. With evolving understanding about CARs and new constructs under investigation, there is optimism that future products will improve the safety and efficacy from the current standard of care.