It is provided a method of expanding dendritic (DC) cells and/or natural killer (NK) cells in vivo in a patient comprising the steps of producing a graft of stem and progenitor cells cultured with UM171 or analogues therefrom and expanded before being administered to the patient. The expansion or increase in dendritic (DC) cells and/or natural killer (NK) cells population in the patient results in an increase immune response reducing transplant related mortality (TRM), severe graft-versus-host disease (GVHD), relapse, and/or severe viral infections.
