In our study, using NK-92 as a model, we investigated the different effects of soluble IL15, and a membrane bound protein consisting of human IL-15 and human IL-15Rα fused by flexible linkers (IL-15/IL-15Ra) to overcome NK potency and expansion capacity limitations in vitro and in a murine xenograft model for CD19 hematologic malignancies. Here, IL15 is linked to hematologic disorder.