Nevertheless, ATRA/ATO-induced clinical remissions are often associated with differentiation syndrome [10] along with systemic inflammatory response syndrome, increased activity of cytochrome P-450, upregulation of multidrug resistance protein 1 (MDR1), inhibition of thioredoxin reductase and a blunted effect of ATRA following the mutation of PML/RARα in the LBD of certain leukemic clones [3]. Here, ABCB1 is linked to systemic inflammatory response syndrome.