Our research focuses on novel approaches to blood progenitor/stem cell transplantation. Transplantation is the only available curative treatment for certain blood disorders and aggressive leukemias. However, patients requiring blood progenitor/stem cell transplantation need a suitably matched bone marrow donor. Also, it takes weeks to months for blood cells to recover in patients after transplantation, leaving them vulnerable to complications such as infections and bleeding during this time. Cord blood is a more readily available source of blood progenitor/stem cells, than bone marrow donors. But its use is mainly limited to younger children because it contains a very low dose of cells that is not sufficient for older patients. A method to expand the number of cells would make it possible to use cord blood as the source of blood progenitor/stem cells for older patients, and hasten the recovery of blood cells after transplantation, thus reducing complications. We studied the use of a genetically modified form of the growth factor receptor c-Mpl for the controlled expansion of cells in cord blood. Our laboratory studies show that this strategy expands blood progenitor cells and induces the production of red blood cells by increasing cell growth, survival, and activation of red cell genes, making it a potential strategy for expediting blood cell recovery after transplantation.