Cell adhesion molecule ITGB2 promotes CAR-T cell therapy in B-cell malignancies.

目的分析复发/难治性急性B淋巴细胞白血病（R/R B-ALL）自体CD19嵌合抗原受体T细胞（CAR-T细胞）制备过程中，培养体系中残留白血病细胞导致CD19 CAR转入白血病细胞的特征和体外杀伤研究。方法①收集30例接受CD19 CAR-T细胞治疗的R/R B-ALL患者及6例健康志愿者外周血单个核细胞（PBMC）；②流式细胞术分析R/R B-ALL患者PBMC经CD3磁珠分选后及体外培养过程中体系白血病细胞残留情况；③患者及健康志愿者PBMC CD3+ T细胞转染CD19 CAR及CD22CAR慢病毒，制备CD19 CAR-T、CD22 CAR-T细胞；④复苏Nalm-6细胞株，CD19 CAR慢病毒转染Nalm-6细胞，制备CD19 CAR-Nalm-6细胞，同时转染患者原代ALL细胞；⑤流式细胞术检测转染率；⑥CCK-8法检测细胞增殖；⑦乳酸脱氢酶（LDH）法检测CD19 CAR-T、CD22 CAR-T细胞对Nalm-6细胞及CD19 CAR-Nalm-6细胞杀伤活性。结果①30例接受CD19 CAR-T细胞治疗的R/R B-ALL患者中，2例CD3+ T细胞中发现3.32％、2.04％的白血病细胞残留，随体外培养时间延长，在培养第4天，白血病细胞完全消失。②体外培养中CD19 CAR-Nalm-6细胞增殖率高于Nalm-6细胞。③效靶比为1∶1且共培养24、48、72 h，CD19 CAR-T细胞对Nalm-6细胞的杀伤活性高于CD19 CAR-Nalm-6细胞；与CD19 CAR-T细胞相比，CD22 CAR-T细胞对CD19 CAR-Nalm-6细胞的杀伤活性更高。④相同效靶比情况，单独应用CD22 CAR-T细胞对CD19 CAR-Nalm-6细胞的杀伤活性高于CD19 CAR-T联合CD22CAR-T细胞。结论CD19 CAR-T细胞制备过程中培养体系残留白血病细胞可能会导致CD19 CAR被引入白血病细胞中而导致CD19 CAR-T细胞治疗失败，在细胞制备过程中需要检测培养体系中白血病细胞的残留情况。CD22 CAR-T细胞治疗可作为上述情况的挽救治疗措施之一。

Sequential CD19 and CD22 CAR-T Therapy in Relapsed/Refractory Acute Lymphoblastic Leukemia

Phase 2 Study of CD19 CAR T Cells with a Fully Human Binder for Large B-Cell Lymphoma in Relapse or Progression after a Murine Binder-Bearing CD19 CAR T-Cell Therapy

BackgroundDespite continuous improvements in the new target and construction of chimeric antigen receptor (CAR)-T, relapse remains a significant challenge following CAR-T therapy. Tumor microenvironment (TME) strongly correlates with the efficacy...

PI3 Kinase Pathway Regulates CAR T Cell Trogocytosis

The feasibility of additional CD19-targeted cellular therapy in relapsed/refractory B-ALL with re-emergence of CD19 antigen after prior CD19-negative relapse.

Cellular Immunotherapies for Leukemia Patients

CAR-T Cells Targeting BAFF-Receptor for B-Cell Malignancies: A Potential Alternative to CD19

BackgroundFor CD19-positive relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL) after treatment with murine CD19 (mCD19) CAR-T, the reinfusion of mCD19 CAR-T cells may be ineffective due to anti-mouse single-chain variable fragment (scFv) antibody caused by mCD19 CAR. To overcome this immunogenicity, we applied humanized CD19 (hCD19) CAR-T cells to treat r/r B-ALL patients with prior mCD19 CAR-T therapy.MethodsNineteen pediatric and adult patients were included, 16 relapsed after and 3 were primarily resistant to mCD19 CAR-T. All patients presented with more than 5% blasts in bone marrow and/or extramedullary disease, and still showed CD19 antigen expression. Humanized CD19-CARs were lentiviral vectors carrying a second generation CAR with 4–1-BB co-stimulatory and CD3ζ signaling domains. Patient-derived cells were collected for producing CAR-T cells, the median dose of infused hCD19 CAR-T cells was 2.4 × 105/kg (range, 1.0–18.0 × 105/kg).ResultshCD19 CAR-T resulted in a complete remission (CR) rate of 68% (13/19). Among 13 remission patients, 11 underwent allogeneic hematopoietic cell transplantation (allo-HCT) (3 were second HCT) and 10 remained in CR; the event-free survival rates at 12–18 months were 91% in 11 patients received following allo-HCT and 69% in all CR patients. Six cases had no response to hCD19 CAR-T, 3 died of disease progression; another 3 received salvage second transplantation, of them, 2 relapsed again (one died). Cytokine release syndrome (CRS) occurred in 95% (18/19) of patients, most CRS events were grade 1 and grade 2 (n = 17), there was only one grade 4 CRS. Two cases experienced grade 1 neurotoxicity.ConclusionsHumanized CD19 CAR-T cell therapy could be a treatment option for CD19-positive B-ALL patients who relapsed after or resisted prior murine CD19 CAR-T, hCD19 CAR-T followed by allo-HCT provided a longer remission in CR patients. Nevertheless, the prognosis of non-responders to hCD19 CAR-T remained dismal.Trial registrationChinese Clinical Trial Registry/WHO International Clinical Trial Registry (ChiCTR1900024456, URL: www.chictr.org.cn); registered on July 12, 2019.

NKTR-255 Vs Placebo to Enhance Complete Responses and Durability Following CD19-Directed CAR-T Therapy in Patients with Relapsed/ Refractory (R/R) Large B-Cell Lymphoma (LBCL)

A Feasibility and Safety Study of CD19 and CD22 Chimeric Antigen Receptors-Modified T Cell Cocktail for Therapy of B Cell Acute Lymphoblastic Leukemia

Dasatinib and CAR-T Cell Therapy for Newly Diagnosed Ph-Positive Acute Lymphoblastic Leukemia in Adults

Objective: To compare the activity difference of the high affinity humanized CD19 chimeric antigen receptor (CAR)-T cells and murine CD19 CAR-T cells. Methods: Peripheral venous blood T cells from 8 healthy volunteers were collected and infected with humanized and murine CD19 CAR lentivirus. Human and murine CD19 CAR-T cells were prepared and cell proliferation was detected by cell counting kit-8 (CCK-8) method. The cytotoxicity of CD3(+) T cells, humanized and murine CD19 CAR-T cells to NALM-6 cells was detected by lactate dehydrogenase assay. Thirty BAL B/c nude mice transplanted with NALM-6 cells were randomly divided into 3 groups with 10 mice in each group and injected humanized CD19 CAR-T cells, mouse CD19 CAR-T cells and control CD3(+) T cell via tail vein, respectively. The proportion of NALM-6 cells in peripheral blood and the proportion of CD19 CAR-T cells in T cells from the vein of the inner canthus were detected by flow cytometry. The overall survival of BAL B/c nude mice was observed. Results: The proliferation of mouse and humanized CD19 CAR-T cells were (68.50±0.93)% and (80.63±1.41)%, respectively (t=20.353, P<0.001) after cultured in vitro for 24 hours, and were (91.38±1.41)% and (148.13±1.25)%, respectively (t=85.364, P<0.001) after cultured for 48 hours. When the effect to target ratio was 1∶1, there was no difference between the humanized and murine CD19 CAR-T cell group after co-culture for 24 hours (P=0.169), while the killing activity of humanized CD19 CAR-T cells against NALM-6 cells was higher than that of murine CD19 CAR-T cells (P<0.01) after 48 hours of co-culture. When the effect to target ratio was 4∶1, the cytotoxicity of humanized CD19 CAR-T cells against NALM-6 cells was higher than that of murine CD19 CAR-T cells in co-culture for 24 and 48 hours (P<0.01). On the seventh day of CD19 CAR-T cell therapy, the proportion of NALM-6 cells in the peripheral blood of BAL B/c nude mice decreased to the lowest level in the humanized CD19 CAR-T cell group and the murine CD19 CAR-T cell group. After 21 days, the proportion of NALM-6 cells in the murine CD19 CAR-T cell group was higher than that in the humanized CD19 CAR-T cell group (P(21 d)=0.001, P(28 d)<0.001, P(35 d)<0.001). The proportion of humanized and murine CD19 CAR-T cells in the peripheral blood reached the peaks after 7 days of therapy, and the proportion of humanized CD19 CAR-T cells was higher than that of murine CAR-T cells (P(7 d)=0.002). The CD19 CAR-T cells disappeared in the peripheral blood in the murine CD19 CAR-T cell group after 14 days of therapy, while in the humanized CD19 CAR-T cell group it disappeared after 21 days of therapy. The median survival of BAL B/c nude mice in the murine CD19 CAR-T cell group and the humanized CD19 CAR-T cell group was 42 days and 63 days, respectively (χ(2)=15.382, P<0.001). Conclusions: High affinity humanized CD19 CAR-T cells have stronger proliferation, higher cytotoxicity and longer survival time compared with those of murine CD19 CAR-T cells. The results indicate that the clinical efficacy of humanized CD19 CAR-T cells would be better than that of murine CD19 CAR-T cells.

High IL-15 Serum Concentrations Are Associated with Response to CD19 CAR T-Cell Therapy and Robust In Vivo CAR T-Cell Kinetics

Targeting CAR T Resistance Due to CD19 Loss with CD79b-Specific CAR T Cells in B-Cell Malignancies