Strategies for circumventing transplant rejection: modification of cells, tissues and organs

New technologies may permit the therapeutic use of transplanted cells or whole organs to be extended to the treatment of a wider range of diseases and a greater number of individuals. At present, the replacement of failing organs or the treatment of disease by transplantation is restricted by the need for co-administration of toxic immunosuppressive drugs to prevent rejection, and the limited availability of donor organs. Recent advances, however, suggest that genetically engineered or immunologically modified donor organs or cells can eliminate the need for host immunosuppression and can allow organ and cell survival across species. Transplantation could thus become a widespread therapeutic approach in the next century.