Breakthrough for "Bubble Boy" Disease

For people born with severe combined immunodeficiency (SCID), exposure to seemingly harmless germs can be deadly. But breakthroughs in stem cell research bring new hope to the search for a cure.

SCID is a severe genetic defect more commonly known as "bubble boy disease." Individuals with SCID are extremely susceptible to germs and disease; even benign germs can be fatal. Patients must live essentially in a hospital or in isolation until the disease is successfully treated. Previously, SCID patients required continuous treatment over their lifetime to prevent sickness and death.

"Without treatment, these children generally die within months of birth," lead author Alessandro Aiuti, M.D., of the San Raffaele Telethon Institute for Gene Therapy in Italy, told Ivanhoe. "Unfortunately, with this type of disease, the success rate is very low."

Now, researchers believe stem cell transplants could effectively treat and potentially cure a form of SCID caused by a deficiency of the adenosine deaminase gene, or ADA-SCID. Researchers treated eight children with ADA-SCID. They removed autologous hematopoietic stem cells from the patient's bone marrow, combined stems cells with the ADA gene, then transplanted the stem cells back into the patient's body.

All study participants are healthy, even six years after treatment. The stem cells integrated into the patients' marrow, and patients are now able to generate healthy blood cells. The children no longer need to be isolated to survive.

"Patients are alive and going to school, and they no longer need to be protected and completely isolated from other people as they were before," Dr. Aiuti said. "This is good news for both the children and the gene therapy field, which has been struggling for many years."

The children have continued to grow and develop because the ADA genes sustain activity in the blood cells. Tests reveal the presence of antigen-specific antibodies, which help the immune system fight bacteria and viruses. Five patients had antibody levels high enough to discontinue treatment of supplemental antibodies.

"Based on the experience of bone marrow transplant, this treatment will be life long," Dr. Aiuti said. "Hopefully, they will not need follow-up treatment. The children who completely reconstituted did not need follow-up treatment in years following the study."

Dr. Aiuti said this research opens the doors for future breakthrough treatments of ADA-SCID.

"We have the demonstration," she said. "By improving therapy, the bar can be raised."