The onset of toxicity is mediated by the robust activation of CAR-T cells upon their encounter with antigen expressing tumor cells and the release of cytokines including IFN-γ, IL-2, IL-6, TNF-α, which can further activate bystander immune cells including monocytes and macrophages to secrete additional cytokines and chemokines including IL-10, IL-6, IL-8, CXCL9, CXCL10, MIP-1α and MIP-1β [196,201,205,210,219,228,229,230,231]. The gene discussed is IL6; the disease is neoplasm.