[Gene therapy for adenosine deaminase (ADA) deficiency: review of the past, the present and the future].

ADA deficiency is the first disease being treated by gene therapy. Since the first trial of gene therapy performed ten years ago, more than 10 patients including our case with ADA deficiency have been treated by the gene therapy with different clinical protocols. In contrast to the recent successful report for X-SCID patients, however, no curative effect of gene therapy for ADA deficiency has been achieved at the moment. In this chapter, I would like to review the past, the present and the future of gene therapy for ADA deficiency, and discuss an issue, especially PEG-ADA therapy, regarding the prospect for stem cell gene therapy for the disease.