Reports of neoplasia related to insertional activation of protooncogenes by retroviral vectors have raised serious safety concerns in the field of gene therapy. Modification of current approaches is urgently required to minimize the deleterious consequences of insertional mutagenesis. In this issue of the JCI, Adjali and colleagues report on their treatment of SCID mice lacking the 70-kDa protein tyrosine kinase, ZAP-70, with direct intrathymic injection of a ZAP-70–expressing T cell–specific lentiviral vector, which resulted in T cell reconstitution. Using lentiviral vectors and in situ gene transfer may represent a safer approach than using retroviral vectors for ex vivo gene transfer into HSCs, avoiding 3 factors potentially linked to leukemogenesis, namely HSC targets, ex vivo transduction and expansion, and standard Moloney leukemia virus–based retroviral vectors.
Ruth Seggewiss, Cynthia E. Dunbar
Guidelines: The Editorial Board will only consider letters that we deem relevant and of interest to our readers. We will not post data that have not been subjected to peer review, nor will we post letters that are essentially a reiteration of another letter. We reserve the right to edit any letter for length, content, and clarity. Authors will be notified by e-mail if their letters were accepted. No appeals will be considered.
Specific requirements: All letters must be 400 words or fewer. You may enter the letter as plain text or HTML. The author's name and e-mail address are required, and will be posted with the letter. All possible conflicts of interest must be noted, even if they are not posted. If you wish to include a figure (keep in mind that non-peer-reviewed data will not be posted), please contact the editors directly at firstname.lastname@example.org.