Anti-FcμR CAR T cells secrete a panel of cytokines and lytic proteins after coincubation with CLL cells. Patients’ T cells with anti-FcμR CAR, anti-CD19 CAR, or without CAR (w/o), respectively, were coincubated with autologous CLL cells (10⁵ cells) for 24 hours (n = 4) in a CAR T-cell-to-CLL cell ratio of 5:1. CLL cells without added T cells served as additional control. The various proteins in the culture supernatant were detected using the bead-based “LEGENDplex multi-analyte assay.”