美国宾夕法尼亚大学Denise E. Sabatino研究组通过对A型血友病狗进行AAV基因治疗的长期研究发现肝细胞的克隆扩增。2020年11月16日，国际知名学术期刊《自然—生物技术》在线发表了这一成果。
Title: A long-term study of AAV gene therapy in dogs with hemophilia A identifies clonal expansions of transduced liver cells
Author: Giang N. Nguyen, John K. Everett, Samita Kafle, Aoife M. Roche, Hayley E. Raymond, Jacob Leiby, Christian Wood, Charles-Antoine Assenmacher, Elizabeth P. Merricks, C. Tyler Long, Haig H. Kazazian, Timothy C. Nichols, Frederic D. Bushman, Denise E. Sabatino
Abstract: Nine dogs with hemophilia A were treated with adeno-associated viral (AAV) gene therapy and followed for up to 10 years. Administration of AAV8 or AAV9 vectors expressing canine factor VIII (AAV-cFVIII) corrected the FVIII deficiency to 1.9–11.3% of normal FVIII levels. In two of nine dogs, levels of FVIII activity increased gradually starting about 4 years after treatment. None of the dogs showed evidence of tumors or altered liver function. Analysis of integration sites in liver samples from six treated dogs identified 1,741 unique AAV integration events in genomic DNA and expanded cell clones in five dogs, with 44% of the integrations near genes involved in cell growth. All recovered integrated vectors were partially deleted and/or rearranged. Our data suggest that the increase in FVIII protein expression in two dogs may have been due to clonal expansion of cells harboring integrated vectors. These results support the clinical development of liver-directed AAV gene therapy for hemophilia A, while emphasizing the importance of long-term monitoring for potential genotoxicity.