Fueling chimeric antigen receptor T cells with cytokines

Chimeric antigen receptor (CAR)-T therapy started a new era of tumor treatment, especially for hematological malignancies. However, many challenges remain, including low-level proliferation and short-term persistence, insufficient CAR T-cell trafficking, suppressive tumor microenvironment (TME), frequent adverse events and the unaffordable manufacturing process. Cytokines are pleiotropic hormones involved in multiple processes of immunity, including activation, expansion, differentiation, and migration of immune cells. Both pre-clinical models and clinical trials showed that armoring CAR-T cells with cytokines strengthened the anti-tumor responses of CAR T cells. This review looked into the key role of cytokines as a promoter of anti-tumor activities of CAR-T cells and consequently a facilitator of clinical translation, mainly, from cytokines of the common γ-chains family, chemokines and chemokine receptors, immunosuppressive molecules and pro-inflammatory cytokines.