Gene therapy has long been considered an attractive alternative therapeuticoption for X-linked chronic granulomatous disease (CGD), a genetic defectaffecting the expression of the gp91phox molecule and characterized by impairedsuperoxide production in phagocytic cells with consequent susceptibility tolife-threatening abscesses and/or granuloma formations in the skin, liver,lungs, or bone of affected patients 30. This evidence concerns the gene CYBB and chronic granulomatous disease.