The effect of blocking was very minor and only present in KIR+ subsets which was in contrast to a previous study where Monalizumab, a clinical grade NKG2A blocking antibody, improved the cytotoxicity of low dose (250 U/ml) activated KIR− NKG2A+ NK cells against a variety of primary tumor cells (10). This evidence concerns the gene KIR3DL1 and neoplasm.