There's Now a Cure for Bubble Boy Disease—Here's What That Means

Doctors have found a cure for "bubble boy disease," according to research published today in the New England Journal of Medicine.

The inherited immune system disorder is technically called X-linked severe combined immunodeficiency (SCID), and it affects mostly boys. Bubble boy disease is the most common SCID condition, and the frequency of the illness isn't known. However, the National Institutes of Health (NIH) estimates that it affects at last one in every 50,000 to 100,000 babies.

So why is X-linked SCID nicknamed "bubble boy disease"? If a child tests positive for the disease at birth, they can't necessarily do activities that other children can do. A child with X-linked SCID can't fight off infections the way a healthy child can because their immune system doesn't function properly. They have to live inside a "bubble" to keep from coming into contact with germs that wouldn't hurt a healthy person but could kill someone whose immune system doesn't work. For example, David, pictured above, had to live in this plastic "bubble" while doctors searched for a cure for his condition.

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Another example is Ja'Ceon Golden, who was born in 2016 and wasn't able to leave the hospital after he tested positive for the condition. He had to live in isolation to minimize his risk of getting an infection. Golden's aunt and caretaker Dannie Hawkins spoke to CNN about what happened when she heard of her nephew's diagnosis. "At that moment, all kinds of things were going through my mind," she said.

But Golden participated in the trial that led to the newly published research, and the therapy the doctors discovered has cured him. He's now able to go outdoors. Hawkins spoke to CNN about getting to take her nephew outdoors for the first time in his life. "Just to see him look at the cars and just smile: It was a blessing," she said.

Bubble boy disease is caused by mutations in a gene called IL2RG on the X chromosome. "The IL2RG gene provides instructions for making a protein that is critical for normal immune system function. This protein is necessary for the growth and maturation of developing immune system cells called lymphocytes," the NIH explains.

Lymphocytes have three jobs: The first is to protect the body from harmful invaders. They are also in charge of making antibodies, which are blood proteins that identify toxins that need to be destroyed. Lastly, they are tasked with regulating the immune system. "Mutations in the IL2RG gene prevent these cells from developing and functioning normally. Without functional lymphocytes, the body is unable to fight off infections," the NIH says.

In other words, an infection that most of us would be able to survive could kill an infant with bubble boy disease, and this is why children with the illness are kept in isolated areas. Golden's aunt told CNN she got in the habit of constantly cleaning her hands to minimize the risk of exposing her nephew to germs. She also heated the water he would bathe in ahead of bath time so that the water he was in would be sterile.

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The new cure for bubble boy disease is a gene therapy technique that works to reconstruct the immune system. Doctors take stem cells from the bone marrow of a child with the condition, insert a normal IL2RG gene into those cells, then infuse those cells back into the child. The whole process works in about 10 days, lead study author Ewelina Mamcarz, MD, of St. Jude Children's Research Hospital's bone marrow transplant department, tells Health. During those 10 days, the patients are given two low doses of chemotherapy.

Eight infants with bubble boy disease were given the treatment from September 2016 to March 2018. "All the patients were alive and well as outpatients at a median follow-up of 16.4 months and had normal growth with respect to weight and height," the new research says. Dr. Mamcarz and her co-authors are very optimistic about the trail's results. "This approach led to broad immune reconstitution," the report says.

"We were able to fully restore the immune system on most of the patients in this study. That means they recovered all three types of immune cells," Dr. Mamcarz says.

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While the treatment has given babies like Golden improved quality of life, questions remain about the long-term benefits of the cure.

"The question will become: Will it be a durable cure? Will it last 10, 20, 50 years for these children? And only time will tell," James Downing, MD, president of St. Jude Children's Research Hospital, told CNN. "This is the first time we've seen a total reconstruction of the immune system, which has provided the ability for these children to get out of isolation. So we're comfortable, I think, at this point, saying that this is a cure. Only time will say: Will this be a durable, lifelong cure?"

For Hawkins, the cure is nothing less than a remarkable step up from the life her nephew had pre-treatment, a life that meant the closest he got to fresh air was a hospital window. "All he could do was see the cars out the window," she told CNN. "I would put him to the hospital window so he could see people walk and cars go by."

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