In fact, in vitro application of the CD3/CD33 engaging bispecific antibody resulted in up-regulation of PD-L1 expression on primary AML cells, up-regulation of PD-1 expression on T-cells, with reversal of the killing inhibition through PD-1/PD-L1 blockade [36]. This evidence concerns the gene PDCD1 and acute myeloid leukemia.