KIR2DL1 and acute lymphoblastic leukemia: Interestingly, upon in vitro stimulation with ALL cells, KIR2DL1 educated NK cells (HLA-C1/C1) show a higher cytotoxic activity than KIR2DL1 educated NK cells from HLA-C1/C2 and HLA-C2/C2 (96) (Figure 4A).