Impairment of NK Cell Mediated Immune Surveillance Against Acute Myeloid Leukemia

Abstract

Natural killer (NK) cells are cytotoxic lymphocytes contributing in innate immune responses that recog- nize and kill virus-infected and tumor cells without prior stimulation. Several clinical trials have indicat- ed that NK cell-based immunotherapy represents a promising antitumor immunotherapeutic approach due to their key role in mediating graft versus leukemic effect against hematological malignancies, par- ticularly acute myeloid leukemia. However, the antitumor activity of NK cells is inhibited as a result to immune-evasion mechanisms developed by malignant cells through alterations in the expression of activating and inhibitory receptors and their ligands, as well as secretion of soluble NK-inhibitory mediators. Until now, the exact molecular mechanisms involved in these alterations are still not defined.