Blast-derived microvesicles in sera from patients with acute myeloid leukemia suppress natural killer cell function via membrane-associated transforming growth factor-β1

Background Natural killer cell cytotoxicity is decreased in patients with acute myeloid leukemia in comparison to that in normal controls. Tumor-derived microvesicles present in patients’ sera exert detrimental effects on immune cells and may influence tumor progression. Design and Methods We investigated the microvesicle protein level, molecular profile and suppression of natural killer cell activity in patients with newly diagnosed acute myeloid leukemia. Results The patients’ sera contained higher levels of microvesicles compared to the levels in controls ( P P P Conclusions We provide evidence for the existence in acute myeloid leukemia of a novel mechanism of natural killer cell suppression mediated by tumor-derived microvesicles and for the ability of interleukin-15 to counteract this suppression.