[Present status and future prospects of human gene therapy]

Gene therapy is defined as the treatment of diseases by the transfer of genes into cells. This concept originally emerged as the definitive therapy for genetic disease. However, acquired diseases such as cancer and AIDS are now being considered as its potential targets. The first clinical trial of human gene therapy was in 1990 at the NIH in a 4 year old girl with fatal severe combined immunodeficiency caused by adenosine deaminase deficiency. Blood transfusion with genetically corrected lymphocytes resulted in significant improvement of the function of her immune system. The patient was discharged from hospital and is attending a public school. Immunotherapy for cancer using tumor cells transduced with genes for various cytokines and major histocompatibility antigens (tumor vaccine) has also been initiated at many research hospitals. In addition, gene therapy protocols targeting familial hypercholesterolemia, hemophilia B, cystic fibrosis are underway. Currently, more than 50 clinical protocols have been approved by the Recombinant DNA Advisory Committee at the NIH, and more than 100 patients have already been treated by this innovative therapeutic strategy.