The adoptive infusion of natural killer (NK) cells is a promising immunotherapy for cancer, viral infections, and aging-associated diseases. Clinical responses have been linked to enhanced cytotoxicity and sustained NK cell persistence in vivo. While preconditioning and/or cytokines support improvement in vivo persistence of infused NK cells. However, the effects of ex vivo expanded natural killer (eNK) cells infusion on peripheral blood NK cells-without these interventions-remain unclear....