TNF and leukemia: These findings support a role for TNF-α in the induction of NK cell apoptosis.[21] To reinforce the role of CD16 in AML-induced NKCAs, we have shown that cross-linking of CD16 on NK cells by the Fc fragment of SY11B5, a mAb with specificity for CD157 antigen expressed on leukemia cells but not on NK cells, induces CD16 down-regulation and enhances NK cell apoptosis.