Doctors used gene therapy to cure babies who were born with Severe Combined Immunodeficiency (SCID), a rare and life-threatening disease marked by little or no immune system.

Bubble Boy

The disease is also known as boy in the bubble syndrome. It more often affects boys.

The public became more aware of SCID because of David Vetter, who became known as the bubble boy. For more than a decade, he lived at the Texas Children's Hospital inside a protective bubble to protect him from otherwise innocuous pathogens that can be fatal for him.

He also wore airtight suits to prevent him from contacting bugs that his immune system could not fight.

Bone Marrow Transplant

SCID patients are typically treated with bone marrow transplant early in life before an infection happens. Transplants made in the first three months of life tend to have the highest success rates, but while transplants are life-saving, they can only partially restore the immunity of the patient.

A better treatment, however, is now on the horizons. Researchers from St. Jude Children's Research Hospital in Memphis developed a new way to treat the disease. Doctors now call the new therapy a cure.

"So far it really looks good," said Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases. "To me, this looks promising."

'Cure' For Bubble Boy Disease

Ewelina Mamcarz, from the St. Jude Department of Bone Marrow Transplantation and Cellular Therapy, and colleagues involved eight infants with a type of SCID called SCID-X1. They treated the babies with a gene therapy that involved collecting some of the patients' blood cells, using modified HIV to insert the normal gene missing in these patients, and returning these altered cells through an IV.

After a few months, seven of the boys developed normal levels of healthy immune cells. The eighth received a second dose but is now well. Six to 24 months later, all of the children are producing the type of cells needed to fight infection. Some received vaccines to further boost their immunity to disease.

No serious or lasting effects have so far been observed. Researchers, however, said the patients will be studied to see if the results last.

"These patients are toddlers now, who are responding to vaccinations and have immune systems to make all immune cells they need for protection from infections as they explore the world and live normal lives. This is a first for patients with SCID-X1," Mamcarz said.

Researchers described the gene therapy in a study published in the New England Journal of Medicine on Wednesday.