Is a safety preassessment of gene targeted epidermis possible?
While the hematopoietic community debates on improvements and safety measures for gene transfer to avoid undesired effects such as those that arose during the successful gene therapy trial of X-linked severe combined immunodeficiency (SCID X1) children,12 cutaneous gene therapists can simply stand by their old statement that a simple excision of the grafted gene-modified area would address the undesired problem. A less invasive and elegant situation is, however, envisioned. Would it be possible to assess the risk(s) of genetically modified skin prior to patient grafting? The fantastic in vitro growing capacity and ease of ex vivo genetic manipulation of epidermal stem cells, unavailable when working with hematopoietic stem cells, allow us to support that possibility. In an ideal setting (Figure 3), a single isolated gene-targeted holoclone (epidermal stem cell-derived clone) derived from a patient, could be expanded in vitro and tested for vector gene integrative events using powerful
