CAR-NKT cells induce low cytokine release syndrome by targeting hyperinflammatory macrophages with mitigation from GM-SCF inhibition.

CAR-engineered invariant natural killer T (CAR-NKT) cells have emerged as a promising alternative with comparable antitumor activity and reduced toxicity; however, the mechanisms underlying their improved safety profile remain poorly defined.

Here, we systematically evaluate CRS induced by human CAR-NKT and CAR-T cells using a heavily tumor-bearing xenograft mouse model that recapitulates clinically relevant CRS. Compared with conventional CAR-T cells, CAR-NKT cells induce significantly lower CRS severity across multiple clinical and biochemical parameters. To elucidate the underlying mechanisms, we perform comprehensive single-cell transcriptomic profiling of mouse immune cells, including myeloid and granulocytic populations, across six anatomical compartments: tumor, blood, liver, lung, spleen, and bone marrow.