IFN-γ and IL-6 concentrations are correlated with each other in conventional CAR-T therapy, reflecting the levels of CAR-T expansion and tumor cell killing.86 In 16 out of the 18 patients treated with CAR-T cells co-expressing anti-IL-6 scFv and IL-1Ra, the peak concentration of IL-6 was kept at a low level (<100 pg mL−1) whereas the peak IFN-γ concentration had varied widely (ranging from 2.6 to 4118 pg mL−1). The gene discussed is IL6; the disease is neoplasm.