CAR-T cell therapy did not achieve the desired efficacy in some patients with diffuse large B-cell lymphoma (DLBCL). We conducted single-cell RNA and TCR sequencing as well as methylation chip profiling of peripheral blood samples in DLBCL patients. Patients who achieved complete remission (CR) showed an upward trend in T-cell levels, especially CD8-effector T cells. The responders exhibited T-cell clone expansion, more active T-cell transformation, and frequent cell communication. Highly expressed genes in the CR group were enriched in functions like leukocyte-mediated cytotoxicity and activation of immune response, while the non-CR group was enriched in pathways related to DNA damage and P53-mediated intrinsic apoptotic. More differentially methylated probes (DMPs) were identified in the baseline of the non-CR group (779 vs 350). GSEA analysis revealed that the genes annotated by DMPs were associated with cellular immune functions in T cells, including the generation of chemokines, leukocyte-mediated cytotoxicity, and cell-killing functions. The genes with low expression in the non-CR group exhibited a high methylation status. There is heterogeneity in the cellular, molecular, and epigenetic characteristics of host T cells in patients with different clinical outcomes. Intrinsic defects in T cells are important factors leading to poor efficacy of CAR-T therapy.
CAR-T细胞疗法在部分弥漫性大B细胞淋巴瘤（DLBCL）患者中未能达到预期疗效。我们对DLBCL患者的外周血样本进行了单细胞RNA与TCR测序以及甲基化芯片检测。达到完全缓解（CR）的患者表现出T细胞水平上升趋势，尤其是CD8效应T细胞；应答者呈现T细胞克隆扩增、更活跃的T细胞转化及频繁的细胞通讯。CR组高表达基因富集于白细胞介导的细胞毒性、免疫反应激活等功能，而非CR组则富集在DNA损伤和P53介导的内源性凋亡相关通路。非CR组基线期检测到更多差异甲基化探针（779 vs 350个）。GSEA分析显示，DMPs注释基因与T细胞的免疫功能相关，包括趋化因子生成、白细胞介导的细胞毒性及细胞杀伤功能。非CR组中低表达基因呈现高甲基化状态。不同临床结局的患者宿主T细胞在细胞、分子及表观遗传层面均存在异质性，T细胞的内在缺陷是导致CAR-T疗效不佳的重要因素。
肿瘤(癌症)患者之家