Low-affinity CD19 chimeric antigen receptor (CAR) T cells display enhanced expansion and persistence, enabling fate tracking through integration site analysis. Here we show that integration sites from early (1 month) and late (>3 yr) timepoints cluster separately, suggesting different clonal contribution to early responses and prolonged anti-leukemic surveillance. CAR T central and effector memory cells in patients with long-term persistence remained highly polyclonal, whereas diversity dropped rapidly in patients with limited CAR T persistence. Analysis of shared integrants between the CAR T cell product and post-infusion demonstrated that, despite their low frequency, T memory stem cell clones in the product contributed substantially to the circulating CAR T cell pools, during both early expansion and long-term persistence. Our data may help identify patients at risk of early loss of CAR T cells and highlight the critical role of T memory stem cells both in mediating early anti-leukemic responses and in long-term surveillance by CAR T cells.

低亲和力 CD19 嵌合抗原受体 (CAR) T 细胞表现出增强的扩增和持久性，可通过整合位点分析进行命运追踪。在这里，我们显示早期（1 个月）和晚期（>3 年）时间点的整合位点分别聚集，表明对早期反应和长期抗白血病监测的不同克隆贡献。具有长期持续性的患者中的 CAR T 中枢和效应记忆细胞仍保持高度多克隆性，而在 CAR T 持续性有限的患者中，多样性迅速下降。对 CAR T 细胞产品和输注后的共享整合体的分析表明，尽管产品中的 T 记忆干细胞克隆频率较低，但在早期扩增和长期持续期间，对循环 CAR T 细胞池做出了重大贡献。我们的数据可能有助于识别存在 CAR T 细胞早期丢失风险的患者，并强调 T 记忆干细胞在介导早期抗白血病反应和 CAR T 细胞长期监测中的关键作用。