ICAM1 and acute promyelocytic leukemia: In addition to chemokine increased production, it was demonstrated by our group and others that treatment with ATRA up-regulated the expression of adhesion molecules on blast cells and on endothelial cells, and that dexamethasone counteracted the effects of ATRA.28–30 Our group has demonstrated that NB4 cells (an APL cell lineage) and primary APL cells treated with ATRA enhanced their expression of CD54 and CD18.