By disabling HIV’s ability to replicate and run rampant in a patient’s body, scientists can then safely use the virus as a courier for gene therapy. Blood stem cells are taken from a patient with a genetic disorder and infected with a virus carrying the non-mutated version of the gene, which inserts it into the cells’ DNA. Then, the patient gets their own modified blood cells back.

In a pair of papers published in the journal Science on Thursday, an international team of researchers led by the San Rafaele Telethon Institute for Gene Therapy (TIGET) in Italy reported on their success with the technique in three children with metachromatic leukodystrophy, and three with the rare disease Wiskott-Aldrich Syndrome. The trials began in the spring of 2010, and three years later, all six children are doing well.

via AIDS Virus Modified, Used To Deliver Gene Therapy To Rare Disease Patients.