To determine if CRS was attenuating the GVT effect, adoptive transfer of purified, ex vivo activated TNFα -/- NK cells was performed and significantly attenuated tumor growth, suggesting that TNF-α production from ex vivo CD137L/IL-15/IL-15Rα activated NK cells may be contributing to a CRS that hinders anti-tumor effects. Here, IL15 is linked to neoplasm.