Alysia Padilla-Vaccaro’s twin girls were only a few months old when one of them, Evangelina, was diagnosed with a fatal genetic immune deficiency known as “bubble baby disease.”
“It’s heartbreaking being in a hospital with your newborns,” Padilla-Vaccaro said. “And then having your twins separated? And the diagnosis? It was torture.”
Infants with the disease are born without a functioning immune system, which makes them vulnerable to infection. Babies have to be completely isolated from germs, meaning they often can’t leave their rooms or hug their parents.
Without treatment or a bone marrow transplant, most babies die from bubble baby disease within a year.
But with Evangelina’s diagnosis came a glimmer of hope: doctors told Padilla-Vaccaro that one spot remained in a clinical trial run by Donald Kohn, a stem cell researcher at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA who had been studying bubble baby disease for three decades. Padilla-Vaccaro readily agreed to the trial since Evangelina’s twin sister was not a bone marrow match, leaving the family with no other hope.
23 OUT OF 23
babies successfully treated for the disease so far
Fortunately for Padilla-Vaccaro and the other families in Kohn’s trial, the groundbreaking stem cell therapy has cured all 23 babies who have received it—and cure is not a word that scientists use lightly.
“We avoid using the ‘cure’ word,” Kohn said. “We don’t know what will happen in 15 years. But this is one of the first cases in gene therapy—which has held promise for 25 years—that is bringing an effective treatment.”
Until Kohn’s work, the only hope for a cure was a matching bone marrow transplant, a procedure that is not always successful. Kohn has dedicated his career to understanding the genetic mutations that cause blood disorders like bubble baby disease. His ultimate goal is to create stem cell gene therapy treatments that use a patient’s own blood-forming stem cells to fix the broken genes. This eliminates the disease-causing mutations and the associated debilitating symptoms—in effect, what Kohn calls “a self-transplant.”
In 2001, Kohn began a clinical trial for bubble baby patients and continued to perfect the method through subsequent clinical trials. Evangelina received her transplant in 2012.
“Dr. Kohn walked us through it. He took the time to talk to us for three hours,” Padilla-Vaccaro said. “You think of scientists as not being easy to talk to. But he made it easy for us to understand. He never promised us something he couldn’t deliver. And let me tell you, that man delivered. We’re beyond grateful.”
After Padilla-Vaccaro checked Evangelina into the hospital for the trial, within 24 hours, doctors were removing her blood-forming stem cells. In a week, she was receiving a round of chemotherapy to help her through the treatment. After that, doctors transplanted the modified blood-forming stem cells—by hand, with a syringe, slowly injecting over the course of five minutes. Evangelina stayed in the hospital for four weeks, but she started to show signs of recovery in just two weeks.
“It’s horrible to see your child go through that,” Padilla-Vaccaro said. “They’re just so tiny. You think they’re weak. But she proved us wrong. She was not weak.”
It was within days of Christmas 2012 when Kohn gave Padilla-Vaccaro the good news. “At first he used this jargon, I didn’t know what it meant, about stem cell counts,” she said. “But then he finally said, ‘It worked.’ That moment was the most important moment in my life.”
After the successful trial, Kohn began to study how to apply his method of “self-transplant” to sickle cell disease, a painful genetic disorder that affects 100,000 people in the U.S., most often African Americans. Sickle cell increases the risk of stroke, causes organ damage and shortens life spans. In 2015, Kohn began a clinical trial for sickle cell using the same stem cell gene therapy method applied in his bubble baby trials.
Padilla-Vaccaro, meanwhile, returned home with her daughter. Evangelina was soon able to do everything her twin sister could do—play outside with other children, go swimming and even have a birthday party.
“It was a ‘Bring Your Germs, Let’s Celebrate!’ party,” Padilla-Vaccaro said. She added, “Dr. Kohn and God. Those are the two in my life I owe the world to.”