Optimization of BAFF-R CAR T-cell product cytokine profiling. (A) CAR T-cell products were generated from healthy donors, and CD4⁺ and CD8⁺ T cells were separated before stimulation with either BAFF-R⁺ or BAFF-R⁻ Nalm-6 target cells for 20 hours at E:T ratios of 1:2, 1:1, and 1:0.5. The resulting T-cell subsets were further enriched using anti-CD19–conjugated magnetic beads to deplete Nalm-6 cells. Cytokine concentrations in supernatants were then analyzed using a multiplex cytokine bead–based assay. Results are expressed as mean ± standard deviation of triplicate wells. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001; ns, not significant. Representative data from 2 donors are presented. (B) CD4⁺ T and CD8⁺ CAR T cells were stimulated with either BAFF-R⁺ or BAFF-R⁻ target cells as described above at an E:T ratio of 1:2 for 5 or 20 hours, and cytokine concentrations in supernatants were then analyzed as described above. Representative data from 2 donors are presented. sFasL, sFas ligand; TNF-α, tumor necrosis factor α.