ABSTRACT

I. INTRODUCTION The treatment of congenital diseases of blood cells by gene replacement has been a major focus of gene therapy research for more than the past decade (1,2). Any of the congenital diseases affecting the production or function of hematopoietic and lymphoid cells which can be treated by allogeneic bone marrow transplantation (BMT) should be amenable to treatment by gene insertion into pluripotent hematopoietic stem cells (HSCs). HSCs would be the ideal target for clinical gene therapy of many genetic diseases, because they are long-lived, producing new progenitor cells and mature blood cells for the life of the recipient. Diseases which currently meet these requirements are congenital immune deficiencies, lysosomal storage disorders, leukocyte defects, the hemoglobinopathies, and stem cell defects such as Fanconi’s anemia (Table 1). Because gene therapy would involve autologous transplant of a patient’s own gene-treated cells, the immunological problems encountered in the allogeneic setting, such as graft rejection or graft-versus-host disease, would not be expected to occur.