ATRA prevents both the down-regulation of TM and the up-regulation of TF induced by TNF-alpha48 and by IL-1beta produced by NB4 promyelocytic cells.49 Therefore, although ATRA increases cytokine synthesis by APL cells, it also appears to protect the endothelium against the prothrombotic stimulus of these mediators through a complex set of interactions. Here, TF is linked to acute promyelocytic leukemia.