biostudies-literatureUnknown22(1)An L<h4>Background</h4>For 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.<h4>Methods</h4>Nineteen 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-stimulBMC cancer393https://www.ebi.ac.uk/biostudies/studies/S-EPMC9004014biostudies-literatureHumanized CD19 CAR-T cells in relapsed/refractory B-ALL patients who relapsed after or failed murine CD19 CAR-T therapy.PMC9004014Deng BTong CAn LChang AHLin YZhao DLing ZWu TLiu SZhao YYin ZfalseHumanized CD19 CAR-T cells in relapsed/refractory B-ALL patients who relapsed after or failed murine CD19 CAR-T therapy.<h4>Background</h4>For 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.<h4>Methods</h4>Nineteen 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-stimul2022-01-01T00:00:00Z2022 Apr2025-04-21T17:33:17.397Z2025-04-05T16:40:40.543ZS-EPMC90040143541014810.1186/s12885-022-09489-1