Very early lineage-specific chimerism after reduced intensity stem cell transplantation is highly predictive of clinical outcome for patients with myeloid disease

•Chimerism within PBMC and T cells at day 50 after allo-SCT defines three groups.•Relapse risk for myeloid disease is high if mixed chimerism present in both subsets.•This risk of relapse is 45% at 1 year with associated 5 year survival of only 40%.