CD34 and acute myeloid leukemia: In this trial (RELAZA, Azacitidine for treatment of imminent relapse in MDS or AML patients after alloHCT), at a median of 169 days after alloHCT, 20/59 prospectively screened patients experienced a decrease of CD34+ donor chimerism to <80% and received four azacitidine cycles (75 mg/m2/day for seven days) while in complete hematologic remission.