Fabio Candotti and Marina Cavazzana et al. provide a deeper insight into possible therapeutic approaches for the treatment of immune defects by gene transfer in blood stem cells:

Candotti, F. (2014): Gene transfer into hematopoietic stem cells as treatment for primary immunodeficiency diseases. In: International Journal of Hematology 99 (4), 383–392. doi: 10.1007/s12185-014-1524-z Online Version 

Touzot, F. / Hacein-Bey-Abina, S. / Fischer, A. / Cavazzana, M. (2014): Gene therapy for inherited immunodeficiency. In: Expert Opinion on Biological Therapy 14 (6), 789–798. doi: 10.1517/14712598.2014.895811 Online Version