In the 1980s, getting HIV was the equivalent of a death sentence, inevitably leading to AIDS. But today, thanks to advancements in medicine, HIV carriers can live healthy lives for decades. And in France, researchers have now used HIV to save the lives of two young boys who suffered from a rare and fatal brain disease.

The disease is called adrenoleukodystrophy, or ALD. It attacks the myelin, the tissue that insulates nerves in the central and peripheral nervous systems. One in 18,000 people suffer from the disease, most commonly boys and men, according to the Houston-based Stop ALD Foundation. In the case of boys, they often first show behavioral problems, such as withdrawal and concentration lapses. Eventually, symptoms such as blindness, seizures, loss of muscle control and dementia are known to set in. Within two to five years, patients often face disability or death. The movie, "Lorenzo’s Oil," was based on an ALD case in which parents played by Nick Nolte and Susan Sarandon struggled to find a cure for their son.

A team based at Saint-Vincent de Paul Hospital at Paris-Descartes University—research director Nathalie Cartier and pediatric neurology professor Patrick Aubourg—has worked on their breakthrough treatment for 16 years. In essence, they used HIV as a vector to transfer corrective genes into the patients, penetrating into cell nuclei to introduce healthier genetic material. Before doing this, they harvested cells from the children’s bone marrow, transferred in a functional version of the defective gene via a non-toxic version of an HIV vector, and then reinjected cells to the bone marrow so they could migrate to the brain and correct the disease.

“The two treated patients are doing well: The progression of the disease stopped a few month after the [treatment],” Cartier said, as news of the breakthrough was announced. “Even if we must remain cautious, this analysis shows that we have no specific reason to fear a harmful effect linked to the integration of the ... vector.”

Added Aubourg: “This is the first time a serious brain disease is successfully treated by gene therapy, giving a new impetus for the treatment of human diseases by this type of approach.”

Two years after the treatment, the team has announced that the neural damage has been either halted or reversed. The two patients now attend school and lead normal lives, according to published reports.

The team plans to extend the trial in France and the United States. They feel this kind of therapy can be applied to other diseases as well, such as thalassemia, sickle cell anemia, Wiskott-Aldrich syndrome and metachromatic leukodystrophy.