The present invention provides the new use of composition comprising at least one inhibitor of dipeptidyl peptidase IV (DPP-IV) for increasing migration and homing of haematopoetic progenitor cells in stem cell transplanted recipients, wherein said haematopoetic stem and/or progenitor cells had been treated in vitro with an engraftment enhancing compound, specifically with a prostacyclin analog and a cAMP enhancer before transplantation.