Single-cell CAR T atlas reveals type 2 function in 8-year leukaemia remission

Area of Science:

• Immunotherapy
• Cellular Therapy
• Leukemia Research

Background:

• Chimeric antigen receptor (CAR) T cell therapy shows high initial response rates for acute lymphocytic leukemia (ALL), but relapse remains a significant challenge.
• Understanding the mechanisms behind long-term CAR T cell persistence is crucial for improving patient outcomes.

Purpose of the Study:

• To investigate the molecular factors contributing to ultralong CAR T cell persistence.
• To identify strategies for enhancing CAR T cell efficacy and durability in ALL treatment.

Main Methods:

• Generated a single-cell multi-omics atlas from over 695,000 CAR T cells from pediatric ALL patients and healthy donors.
• Analyzed ligand-receptor interactions and proteomic profiles of patient sera.
• Evaluated CAR T cell function and anti-leukemic activity in a mouse model.

Main Results:

• Elevated type 2 functionality in CAR T cells is linked to prolonged B cell aplasia (median 8.4 years).
• Type 2 CAR T cells regulate dysfunctional subsets and maintain homeostasis; IL-4 addition improves their function and fitness.
• Higher circulating type 2 cytokines correlate with relapse-free survival; type 2high CAR T cells show superior anti-leukemic activity in vivo.

Conclusions:

• Boosting type 2 functionality in CAR T cells is a promising strategy for durable responses in ALL.
• Incorporating IL-4 during manufacturing or pre-infusion priming can enhance CAR T cell efficacy.
• These findings offer potential therapeutic avenues to achieve sustained remission in ALL patients.