Kids With SCID Do Best With Early Diagnosis, Treatment

Larry Hand

July 31, 2014

Infants with severe combined immune deficiency (SCID) who are diagnosed and receive hematopoietic cell transplant at age 3.5 months or earlier have a 94% probability of survival, according to a study published online in the July 31 issue of the New England Journal of Medicine. Older infants who receive a transplant before the onset of a first infection have a 90% survival rate, according to the study.

SCID, or "bubble boy" disease, is usually fatal within a year if untreated.

Sung-Yun Pai, MD, from Boston Children's Hospital, Division of Pediatric Hematology-Oncology, Massachusetts, and colleagues analyzed outcomes data on 240 infants with SCID who received transplants at 25 centers between January 1, 2000, and December 31, 2009. The researchers are part of the Primary Immune Deficiency Treatment Consortium, funded by the National Institute of Allergy and Infectious Diseases.

The overall 5-year survival rate was 74% (178/240 children). However, infants who received transplants at age 3.5 months or younger had a 94% survival rate (64/68 children). In addition, children who received transplants later than 3.5 months of age and with no history of infection had a 90% 5-year survival rate (21/23 children).

The lowest survival rate occurred in children who had transplants later than 3.5 months of age and who had active infection at the time of transplant (50%; 45/91 children).

Most deaths occurred with a year of transplant and resulted from infections (39%; 24/62 deaths) or pulmonary complications (37%; 23/62 deaths).

Donor type had a significant effect on survival. Children who received transplants from matched sibling donors had the highest survival rate, at 97%. Children who received T-cell-depleted transplants from mismatched related donors and did not undergo conditioning had the next highest survival rate (79%; P = .07).

Survival rates for children who received transplants at 3.5 months of age or younger for all transplant types ranged from 78% to 100%, reinforcing the evidence for better results for early diagnosis and treatment. Survival rates for children of any age with no active infection at the time of transplantation ranged from 77% to 100%.

Early Transplantation

"Even after transplantation of grafts from alternative donor types, these very young infants had excellent outcomes that were similar to those of recipients of grafts from matched sibling donors," the researchers write. "Because earlier transplantation is more successful, our findings suggest that newborn screening for SCID and early transplantation may improve survival."

The US Department of Health and Human Services added SCID screening to the Recommended Uniform Screening Panel for newborns in 2010, but to date, only 21 states have incorporated the test in their newborn screening requirements.

"Several million babies have been screened in the United States in the newborn period. You can pick up these babies with great reliability, and you can treat them, and it's just remarkable," R. Rodney Howell, MD, professor and chair emeritus of pediatrics at the University of Miami Miller School of Medicine in Florida, told Medscape Medical News.

For 8 years, Dr. Howell chaired the US Department of Health and Human Services Secretary’s Advisory Committee on Heritable Disorders in Newborns and Children. "At that time, the data for newborn screening and treatment were extremely impressive. This article clearly again demonstrates that it is enormously important to diagnose these babies and treat them early," he said.

"From a patient perspective, just the saving of lives and the saving of morbidity is obviously very important, so by screening patients when they're born, we've found that we can detect these issues and we identify them before they actually have infections," Christopher C. Chang, MD, PhD, chief of the Division of Allergy/Immunology at Nemours Children's Health System, Wilmington, Delaware, told Medscape Medical News.

"We are able to transplant them early, and that's been tremendously successful and a lifesaver for many patients and families," he added. "The hope is that all 50 states will require mandatory SCID screening and we'll be able to continue to save lives."

Dr. Howell emphasized, "It would be hard to imagine that anything we do in medicine is as effective as screening a baby for SCID and treating them in the newborn period."

This research was supported by the National Institutes of Health, the David Center at Texas Children's Hospital, and the St. Baldrick's Foundation. Seven coauthors have reported receiving grant funding from the National Institutes of Health, and 3 coauthors have reported receiving personal fees from several pharmaceutical or biotech companies. The other coauthors and the commentators have disclosed no relevant financial relationships.

N Engl J Med. 2014;371:434-446. Abstract


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