Pre-Treatment peripheral Immune composition can accurately predict CAR-T outcomes in patients with Large B-Cell Lymphoma

Chimeric Antigen Receptor (CAR)-T cell therapy has revolutionized the treatment landscape for relapsed/refractory B-cell malignancies. Despite its success, approximately 60% of patients experience treatment failure, underscoring the need to better understand the determinants of response and resistance. We performed single-cell RNA-sequencing of pre-treatment peripheral blood samples and anti-CD19 CAR-T products from 57 diffuse large B-cell lymphomas (DLBCL), correlating molecular and cellular features with clinical outcomes. At the time of leukapheresis, responders presented elevated levels of CD16+ monocytes and CD4+ effector memory T cells. In contrast, non-responders showed an inflammation-driven gene expression signature across T-cell and myeloid compartments, marked by upregulation of TNF-α response signaling pathways. Notably, the presence of malignant or healthy B cells (13 of 57 patients) was strongly associated with a favorable response. These findings shed light on the immune landscape conducive to successful CAR-T therapy and offer a molecular framework for developing personalized tools to improve patient selection, stratification, and the design of next-generation CAR-T treatments.