MRC1 and neoplasm: IL-18 secretion by the CAR T cells can shift an immunosuppressive microenvironment into a proinflammatory state (20, 22) by increasing the infiltration and activation of CD11b+Gr1– macrophages and MHC-II+CD11c+ dendritic cells, both at the tumor site and systemically, and reducing CD206+MHC-IIlo M2-like polarization tumor-associated macrophages.