IFNG and hepatocellular carcinoma: Accessory cytokines (including IL-12 and IL-18) and T-cell-derived IL-2 are known to be essential to drive NK cell IFN-γ responses during re-stimulation with vaccine antigens.3 Given that increasing CD57 expression correlates with loss of responsiveness to HCC, we predicted that CD56dim CD57− or CD56dim CD57int NK cell populations would show stronger ‘recall’ responses to whole cell pertussis than would CD56dim CD57+ NK cells.