Current gene marking and gene therapy protocols for human bone marrow transplantation

The attraction of marrow progenitor cells as targets for gene therapy 1 – 3 (see Chapter 2) is that they are easily accessible, they can be readily manipulated ex vivo and, in principle, successful transfer into a single self-renewing stem cell is sufficient to repopulate an entire patient with modified cells. However, most early large-animal models suggested that it would be difficult to transduce novel genes into a significant proportion of marrow stem cells and to express the gene in their progeny. 4 – 8 Since the course of clinical gene transfer studies has been guided (not always accurately) by feasibility studies in animal models, the first human gene transfer protocols used mature lymphocytes as their targets (see Chapter 3). 2, 3, 9, 10