Functional reconstitution of the NADPH-oxidase by adeno-associated virus gene transfer

Chronic granulomatous disease (CGD) comprises a heterogeneous group of inherited conditions characterized biochemically by disordered function of a unique multicomponent enzyme system present in phagocytic cells, the NADPH-oxidase. Clinically, it is characterized by recurrent bacterial and fungal infections that are relatively resistant to treatment by conventional means. Curative bone marrow transplantation has been successfully achieved in a small number of cases, but the wider application of this procedure is limited by availability of suitable donor material. Somatic gene therapy would overcome this problem, and several groups have now shown correction of the biochemical defect in hematopoietic cells by retrovirus-mediated gene transfer. However, the failure of the current generation of retroviral vectors to efficiently transduce quiescent cells greatly restricts their potential for gene transfer to pluripotent hematopoietic stem cells. Given these limitations, we have constructed vectors based on adeno-associated virus and used these to transfer a functional copy of the p47phox gene to immortalized B cells derived from patients with p47phox-deficient autosomal recessive CGD. We show stable expression of protein and restoration of NADPH-oxidase function in these cells in the absence of selection. Adeno-associated virus vectors may overcome some of the limitations of retroviral gene delivery systems and may therefore be a useful vehicle for curative gene therapy of CGD and other primary immunodeficiencies.