FChapter.pdf

4. USE OF GENETICALLY MODIFIED STEM CELLS IN EXPERIMENTAL GENE THERAPIES by Thomas P. Zwaka* INTRODUCTION therapeutic strategies. The first successful clinical trials using gene therapy to treat a monogenic disorder ene therapy is a novel therapeutic branch of involved a different type of SCID, caused by mutation modern medicine. Its emergence is a direct of an X chromosome-linked lymphocyte growth Gconsequence of the revolution heralded by the factor receptor.2 introduction of recombinant DNA methodology in the 1970s. Gene therapy is still highly experimental, but While the positive therapeutic outcome was celebrated has the potential to become an important treatment as a breakthrough for gene therapy, a serious drawback regimen. In principle, it allows the transfer of genetic subsequently became evident. By February 2005, three information into patient tissues and organs. Conse- children out of seventeen who had been successfully quently, diseased genes can be eliminated or their treated for X-linked SCID developed leukemia because normal functions rescued. Furthermore, the procedure the vector inserted near an oncogene (a cancer-causing allows the addition of new functions to cells, such as gene), inadvertently causing it to be inappropriately the production of immune system mediator proteins expressed in the genetically-engineered lymphocyte that help to combat cancer and other diseases. target cell.3 On a more positive note