Background and Objectives Differentiation Syndrome (DS) is a treatment complication which can occur in patients treated with acute promyelocytic leukemia (APL) with all transretinoic acid (ATRA) or As2O3. and is characterized by enhanced leukocyte transmigration. As2O3. Phenylbutyrate (PB) and G-CSF are known to potentiate ATRA effects. https://www.chiggate.com/merlot-redbud-tree-sale/