There is provided an isolated pluri-differentiated human mesenchymal progenitor cells (MPCs), a method for isolating and purifying human mesenchymal progenitor cells from Dexter-type cultures, and characterization of and uses, particularly therapeutic uses for such cells. Specifically, there is provided isolated MPCs which can be used for diagnostic purposes, to enhance the engraftment of hematopoietic progenitor cells, enhance bone marrow transplantation, or aid in the treatment or prevention of graft versus host disease.