ABSTRACT
The in vivo gene transfer profile that is required for effective gene therapy depends on the target disease. It includes the target cell-specificity of gene transfer, the efficiency and duration of transgene expression, and the number of transfected cells.1 For example, gene therapy designed for hemophiliacs or other patients who have a deficiency of any plasma protein requires a prolonged production of transgene, but not necessarily cell-specific transduction. Therefore, intramuscular gene transfer of human factor IX by adeno-associated viral vector showed significant therapeutic benefits in hemophiliac patients.2 In marked contrast, the dystrophin gene needs to be definitely transduced into the affected muscle cells, because dystrophin gene transfer to other types of cells will not produce any therapeutic benefit in patients with Duchenne muscular dystrophy. In addition, the number of transfected cells is a very important factor for the efficacy of gene transfer aimed at the treatment of muscular dystrophies.3
