To further evaluate functional capacities of the CAR modified NK cells, cytokine production of GM-CSF, TNF-α, MIP-1α, and IFN-γ of lentivirally/VSV-G and alpharetrovirally/RD114-TR generated CD19-CAR-NK cells (both at MOI 5) was analyzed 3 days after transduction upon expansion in low dose IL-15 alone and in context of co-culturing with target-specific Sup-B15 ALL cells at an E:T ratio of 1:1 for 4 h. This evidence concerns the gene CSF2 and acute lymphoblastic leukemia.