Bai, ZhiliangFeng, BingMcClory, Susan E.de Oliveira, Beatriz CoutinhoDiorio, CarolineGregoire, CélineTao, BoYang, LuojiaZhao, ZiranPeng, LeiSferruzza, GiacomoZhou, LiqunZhou, XiaoleiKerr, JessicaBaysoy, AlevSu, GrahamYang, MingyuCamara, Pablo G.Chen, SidiTang, LiJune, Carl H.Melenhorst, J. JosephGrupp, Stephan A.Fan, Rong2025-01-242025-01-242025-01-242024-10-1710.1038/s41586-024-07762-w2-s2.0-85204770752https://infoscience.epfl.ch/handle/20.500.14299/24382839322664Despite a high response rate in chimeric antigen receptor (CAR) T cell therapy for acute lymphocytic leukaemia (ALL)1–3, approximately 50% of patients relapse within the first year4–6, representing an urgent question to address in the next stage of cellular immunotherapy. Here, to investigate the molecular determinants of ultralong CAR T cell persistence, we obtained a single-cell multi-omics atlas from 695,819 pre-infusion CAR T cells at the basal level or after CAR-specific stimulation from 82 paediatric patients with ALL enrolled in the first two CAR T ALL clinical trials and 6 healthy donors. We identified that elevated type 2 functionality in CAR T infusion products is significantly associated with patients maintaining a median B cell aplasia duration of 8.4 years. Analysis of ligand–receptor interactions revealed that type 2 cells regulate a dysfunctional subset to maintain whole-population homeostasis, and the addition of IL-4 during antigen-specific activation alleviates CAR T cell dysfunction while enhancing fitness at both transcriptomic and epigenomic levels. Serial proteomic profiling of sera after treatment revealed a higher level of circulating type 2 cytokines in 5-year or 8-year relapse-free responders. In a leukaemic mouse model, type 2high CAR T cell products demonstrated superior expansion and antitumour activity, particularly after leukaemia rechallenge. Restoring antitumour efficacy in type 2low CAR T cells was attainable by enhancing their type 2 functionality, either through incorporating IL-4 into the manufacturing process or by priming manufactured CAR T products with IL-4 before infusion. Our findings provide insights into the mediators of durable CAR T therapy response and suggest potential therapeutic strategies to sustain long-term remission by boosting type 2 functionality in CAR T cells.entruetext::journal::journal article::research article