Recombinant adeno-associated virus (rAAV) vectors for somatic gene therapy: recent advances and potential clinical applications.

Adeno-associated virus (AAV) is a single-stranded DNA dependovirus of the family of Parvoviridae that has promising features as a vector for somatic gene therapy. Different recombinant (r) AAV vectors have been generated that seem to have some advantages compared with other vector systems, such as the transduction of terminally differentiated and non-dividing cells, the lack of any apparent pathogenicity, low immunogenicity, relatively high stability of transgene expression, and the potential of targeted integration. Recent improvements in rAAV packaging should allow the generation of sufficient quantities of rAAV for clinical trials. Preclinical studies with rAAV are currently being performed for the treatment of a variety of inherited monogenic defects, such as beta-thalassemia, sickle cell anemia. Fanconi anemia, chronic granulomatous disease, Gaucher disease, metachromatic leukodystrophy and cystic fibrosis, and of acquired diseases, such as HIV infection and non-Hodgkin lymphoma. The diversity of these studies indicates that rAAV might have a broad range of clinical applications. A first clinical trial with rAAV vectors has been started for cystic fibrosis. While several important issues, including safety, tissue tropism and methods to achieve site-specific integration, need further clarification, rAAV seems to have a sufficient number of advantages to be seriously considered as a future gene therapy vector.