Stem cell transplants effective in treating immunodeficiency found through new screening for newborns.
As of January 2016, every newborn in Tennessee is checked for severe combined immunodeficiency. Newborns already had blood drawn from their heels to look for certain disorders. Now the state includes screening for severe combined immunodeficiency with blood from that same heel stick.
What is it?
Severe combined immunodeficiency is a rare genetic disorder that leaves babies at risk of early death from infections that normal immune systems typically fight off. Without treatment, children with the disorder rarely live beyond 2 years.
About 1 in every 50,000 to 100,000 babies in the U.S. are born with severe combined immunodeficiency, which leaves babies with little or no T cells to fight infections. It is sometimes called “bubble boy disease,” referring to David Vetter, a boy with the condition who lived for 12 years inside a germ-free enclosure because more advanced treatments were not available for the disease.
Most newborns with SCID will look completely normal at birth and prior to the newborn screen were only detected after they developed a severe infection or had a previously affected family member.
Stem cell transplants bring new hope
If screening identifies the condition within the first weeks of life, doctors can begin life-saving therapy before symptoms appear. The most effective current treatment is transplanting stem cells from a matched donor to the child. A successful stem cell transplant provides a new immune system for the child and the ability to mount a normal response to infections.
According to a recent article in the New England Journal of Medicine, survival is excellent (more than 90 percent) in infants with SCID who receive a stem cell transplant early without infection, but only 50 percent if they have an active infection at the time of transplant, highlighting the critical importance of early diagnosis.
“Babies born with SCID often look normal at birth, but within the first few months of life they develop serious infections, which can be fatal,” said Yasmin Khan, M.D., assistant professor of Pediatrics in the Division of Allergy and Immunology at Vanderbilt. “The common cold or other common childhood viruses can be serious infections for babies with SCID.”
“Newborn screening is an indispensable tool to help us successfully save the lives of children with SCID. The most important factor of a successful stem cell transplant for infants with SCID is to perform the procedure before infection develops,” said Jim Connelly, M.D., an assistant professor of Pediatrics and stem cell transplant physician at Monroe Carell Jr. Children’s Hospital at Vanderbilt. “By screening for this severe disorder at birth, patients will be identified early and we will start supportive care measures to prevent infection while preparing them for stem cell transplant.”
The newborn screening process
Children born in Tennessee are currently screened for about 60 congenital (present at birth) conditions. This happens in the first few days after birth with the dried blood spot that is collected from newborns.
“If the state public health lab detects a potential problem with a sample, follow-up nurses contact the baby’s primary care provider and one of the regional genetics centers to arrange for in-depth testing,” explains Michael Warren, M.D., assistant commissioner at the Tennessee Department of Health.
A screening showing an abnormal blood count does not always mean a child has severe combined immunodeficiency. The test may also detect other immune deficiencies, which although may be less severe than SCID, still require expert consultation for diagnosis and potential treatment. In the rare case that a child is confirmed to have the condition, children will be referred to specialized clinics, including the new immunodeficiency clinic at Monroe Carell Jr. Children’s Hospital at Vanderbilt.
The immunodeficiency clinic at Vanderbilt is one of the few places in the Southern U.S. where children with severe combined immunodeficiency and other immune deficiencies receive care from a coordinated team of experts who diagnose and treat these deficiencies. Patients will be simultaneously evaluated by a team of immunologists, infectious disease specialists, hematologists, and stem cell transplant physicians with expertise in immunologic diseases.
Because these patients have very complex issues that involve many organ systems, it is important to have this diverse team come together to care for each individual patient. As part of Vanderbilt University, the program is also dedicated to cooperative research to better understand the immune system and provide the best treatment for each and every child that comes through the clinic doors.