ABSTRACT
Manipulations with hematopoietic stem cells (HSC) in the context of bone marrow or peripheral blood stem cell transplantation have become a routine procedure. 1 , 2 Preparative quantities of HSC are readily accessibile. Either marrow or peripheral blood can provide greater than 2 million CD34+ HSC per kilogram of donor weight per harvest or apheresis, respectively. Using human HSC surface markers such as CD34 or AC 133, it is possible to separate and enrich for HSC ex vivo. The intrinsic properties of HSC make them attractive targets for gene transfer. Gene modified HSC should achieve long-term repopulation in the recipient with equally long-term transgene expression. 3 Nowadays the gene transfer into hematopoietic cells comprises 7.4% (44 protocols) of the total number of United States Food and Drug Administration (FDA) approved gene therapy clinical trials.
