Safety considerations in somatic gene therapy of human disease with retrovirus vectors.

Somatic gene therapy of human disease with retrovirus vectors is a new technology with potentially important medical benefits. Although it involves recombinant DNA technologies and modified retroviruses, proper design of the vectors and delivery systems removes most potential foreseen risks. Furthermore, even in the very remote possibility that there is a nontherapeutic biological effect of the treatment, it is unlikely to be a harmful one. Thus, once very safe retrovirus vector-helper cell systems are constructed and in use, safety considerations should not hold up further human trials of retrovirus vectors.