Figure 2. Persistence of CAR T cells around the time of expansion of TCR clonality and CRS-like findings after XRT.

CAR T cells in the patient’s blood were assessed at 5 weeks after CAR T-cell therapy by flow cytometry with a fluorophore-labeled antibody recognizing the surrogate transduction marker that is additionally expressed by the CAR vector. Flow cytometry of peripheral blood mononuclear cells was gated on viable CD3⁺ cells. The red box outlines cells positive for the transduction marker (9.3% of circulating T cells). Note that these persistent gene-modified T cells were predominantly CD8⁺.