August 12, 2014 in Features, Health

New screening allows baby to undergo treatment before ever getting sick

By The Spokesman-Review
 

Four-month-old Ezra Dixon underwent a stem cell transplant at 9 weeks old after a newborn screening found he had severe combined immunodeficiency, or SCID, also known as “bubble boy disease.” His mittens keep him from pulling out his feeding tube.
(Full-size photo)

Ezra Dixon’s heartbeat dropped with every contraction, his umbilical cord circling his neck.

So after Rachel Dixon delivered her second son in Everett on April 7, the Spokane native was just happy to have him. After the drama of his birth, Ezra looked healthy and normal, and his mother slept during the newborn screening that all babies go through – a prick on the heel, his blood dropped on a specimen collection card.

But the screening results, delivered when Ezra was 3 days old, were alarming. The baby had no T cells – the specialists that battle viruses, bacteria and fungi – making him highly vulnerable to infections. More testing confirmed the problem: Ezra had a rare condition called severe combined immunodeficiency, or SCID. It’s also known as “bubble boy disease,” after the Texas boy who lived in a germ-free plastic bubble until he died in 1984 at age 12.

Ezra was the first baby in Washington with the condition to be flagged by the screening, which expanded to include SCID this year. His early diagnosis allowed for early treatment, which doctors and researchers are learning dramatically increases survival rates.

“He’s on the road to recovery now, at 4 months old,” said Rachel Dixon, 24, who moved with her family from Spokane temporarily to Arlington, Washington, where she and her husband attend ministry school. “This is the time when babies in the past were going to the hospital, because they were getting sick and not getting better.”

The addition of SCID to the state’s “newborn screening panel” took three years of lobbying by doctors and researchers and the families whose babies had died. It raised the cost of the mandatory screening for all babies born in Washington.

The payoff, for Rachel and her husband, Zach Dixon, 25: a baby who’s getting healthier, not sicker. They pulled his name from the Bible. It means “help.”

“A little more than 50,000 babies have been born in Washington state this year, and he’s the only one that has been caught,” Rachel Dixon said, holding her baby as she talked at the Ronald McDonald House in Seattle. “And I am so thankful for it. Huh, buddy?”

‘A little breathing room’

The “bubble boy,” David Vetter, was born in 1971 after the SCID-related death of his brother. So his parents and doctors knew he might also have the hereditary condition, and they prepared plastic “isolator bubble” environments while he waited for a matching bone marrow donor or a cure. David died after finally receiving a transplant from his sister, an imperfect match and whose marrow contained a virus that led to lymphoma.

These days, doctors know a lot more about bone marrow transplants, and they view SCID as a pediatric emergency. It’s treated with a transplant as soon as possible.

Newborn screening “gives us a little breathing room with our emergency,” said Dr. Suzanne Skoda-Smith, clinical director for the Division of Immunology at Seattle Children’s Hospital, where Ezra was treated.

A donor’s bone marrow, which produces blood cells, is introduced into the body through a central line. If all goes well, the new immune cells start reproducing, rebuilding the baby’s immune system.

It’s a gradual process.

“I always like to say to families, ‘I planted a seed in a garden,’ ” said Dr. Lauri Burroughs, a physician at Seattle Children’s Cancer and Blood Disorders Center, who also treated Ezra. “It takes months and months and months, even upwards of a year, or longer, to have a full producing garden.”

Ezra received cells drawn from the hip bones of his brother, Judah, who was 20 months old and a perfect match.

Ezra was 9 weeks old. He’d already endured a week of chemotherapy, partly to reduce his existing marrow to make room for new cells. Chemo caused a blistering rash that covered his body and sores throughout his gastrointestinal tract that prevented him from eating. His nutrition came from an IV.

But his brother’s cells took hold. Ezra doesn’t have T cells yet, because one of his chemo drugs prevents them from growing quickly, Rachel Dixon said. But other cell lines are “engrafting.”

“All the other cells in his system are 100 percent Judah,” Dixon said.

The family will stay at the Ronald McDonald House until Ezra hits the 100-day mark post-transplant, making twice-weekly clinic visits to Seattle Cancer Care Alliance for monitoring.

For a year or two, Ezra will receive injections of immunoglobulin, the fraction of blood plasma that contains antibodies.

If all goes well, his SCID will be considered cured: “He should be able to live a completely healthy, normal life,” Rachel Dixon said, “with no restrictions.”

For Judah’s part, Dixon said he said “owie” a few times during diaper changes after the procedure. He asked about the bandages – “Stickers?” – on his back.

Judah spent about three months with his grandparents in Deer Park and Loon Lake, Washington, during Ezra’s treatment. During rare visits to the West Side, Judah could see his brother only through a hospital window, to protect the baby from germs.

“He loves brother,” Dixon said.

Costs and benefits

Of about 50,800 babies screened in Washington so far this year, Ezra is the only one found to have the classic form of SCID.

On New Year’s Day, “bubble boy disease” became the 28th treatable disorder on the state’s panel, a list of hard-to-pronounce maladies unfamiliar to most parents.

Including Ezra, screening has led to definitive diagnoses in 65 babies with conditions such as congenital hypothyroidism, cystic fibrosis and amino acid disorders, according to the state Department of Health. Babies with the conditions on the list usually appear normal at birth.

Washington is among 23 states that screen for SCID. Idaho does not, but the regional lab in Oregon that processes its newborn tests is working toward adding the disorder to its panel, said Carol Christiansen, newborn screening coordinator with the Idaho Department of Health and Welfare.

SCID screening became possible a few years ago with the development of a test that can detect it on the dried-blood cards. The Immune Deficiency Foundation, which advocates for SCID screening in all 50 states, says testing lets doctors treat and likely cure SCID in infants for less money than ongoing and less-effective treatments for children who develop infections.

But the main holdup is cost, Skoda-Smith said.

Skoda-Smith said SCID screening advocates in Washington worked on a cost-benefit analysis with the Department of Health that factored in spending on long-term, intensive care for sick babies as well as the “value” of a baby’s life, a dollar figure used by government agencies.

“SCID had a fabulous cost-benefit analysis, when you sat down and crunched the numbers,” she said.

The addition required new equipment and supplies along with additional personnel at the state’s newborn screening lab, DOH spokesman Donn Moyer wrote in an email.

It bumped up the cost by $8.10 for each baby, boosting the total to $77.40 for each baby. Families or their insurers pay the bill.

Early detection, early transplant

Skoda-Smith and Burroughs both contributed to a new large-scale study that found that SCID babies treated earlier in life fared better. That’s because younger babies are more likely to be infection-free, said Burroughs, who’s also a researcher at Fred Hutchinson Cancer Research Center in Seattle. (The center first reported Ezra Dixon’s treatment on its website.)

The study, led by researchers in Boston, tracked data on babies over 10 years.

Burroughs’ hope for the study’s result: “That more children survive, because they go to transplant early.”

Overall, 74 percent of the 240 babies with SCID tracked in the study lived to be 5 years old, according to the study, published July 31 in the New England Journal of Medicine.

But the survival rate was much higher – 94 percent – for those who underwent stem cell transplants at age 3.5 months or younger. Just 50 percent survived who were older than 3.5 months and had active infections when they got their transplanted cells.

It’s more difficult to treat babies who are already sick. And before screening, “the way they presented was with infection,” Burroughs said.

Some of those infections, added Skoda-Smith, end up killing babies with SCID before they can get transplants.

Ezra’s grandfather David Dixon lives in Loon Lake. Ezra’s other grandparents, John and Marie Layman, live in Deer Park.

David Dixon credits the newborn screening for his grandson’s survival.

“If he’d been born a year earlier,” he said, “he probably wouldn’t be here right now.”


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