IL4 and neoplasm: As reviewed by Knochelmann et al., donor lymphocytes have been further modified in many ways by (1) incorporating targets to multiple antigens, (2) converting suppressive signals such as TGF-β or IL-4 into activating signals, (3) overexpression of chemokine receptors to enhance migration, and (4) secreting cytokines or soluble factors to modulate donor TIL or CAR T cells and endogenous immune cell function to induce a proinflammatory or “hot” tumor microenvironment (7, 8).