Citation

Recchia A, Bonini C, Magnani Z, Urbinati F, Sartori D, Muraro S, Tagliafico E, Bondanza A, Stanghellini MT, Bernardi M, Pescarollo A, Ciceri F, Bordignon C, Mavilio F. Proc. Natl. Acad. Sci. U. S. A. 2006; 103(5): 1457-1462.

Affiliation

Cancer Immunotherapy and Gene Therapy Program, and Bone Marrow Transplantation Unit, Istituto Scientifico H. San Raffaele, Via Olgettina 58, 20132 Milan, Italy.

Copyright

(Copyright © 2006, National Academy of Sciences)

DOI

10.1073/pnas.0507496103

PMID

16432223

PMCID

PMC1360534

Abstract

The use of retroviral vectors in gene therapy has raised safety concerns for the genotoxic risk associated with their uncontrolled insertion into the human genome. We have analyzed the consequences of retroviral transduction in T cells from leukemic patients treated with allogeneic stem cell transplantation and donor lymphocytes genetically modified with a suicide gene (HSV-TK). Retroviral vectors integrate preferentially within or near transcribed regions of the genome, with a preference for sequences around promoters and for genes active in T cells at the time of transduction. Quantitative transcript analysis shows that one fifth of these integrations affect the expression of nearby genes. However, transduced T cell populations maintain remarkably stable gene expression profiles, phenotype, biological functions, and immune repertoire in vivo, with no evidence of clonal selection up to 9 yr after administration. Analysis of integrated proviruses in transduced cells before and after transplantation indicates that integrations interfering with normal T cell function are more likely to lead to clonal ablation than expansion in vivo. Despite the potentially dangerous interactions with the T cell genome, retroviral integration has therefore little consequence on the safety and efficacy of T cell transplantation.

Language: en