Gene Therapy Restores Immunity in Infants with Rare Disease

A baby's hands

Photo: Jules Frazier/Getty

A small clinical trial has shown that gene therapy can safely correct the immune systems of infants newly diagnosed with a rare, life-threatening inherited disorder in which infection-fighting immune cells do not develop or function normally. Eight infants with the disorder, called X-linked severe combined immunodeficiency (X-SCID), received an experimental gene therapy co-developed by NIH scientists. They experienced substantial improvements in immune system function and were growing normally up to 2 years after treatment. The new approach appears safer and more effective than previously tested gene-therapy strategies for X-SCID.

These interim results from the clinical trial, supported in part by NIH, were published Apr. 17 in the New England Journal of Medicine.

Infants with X-SCID, caused by mutations in the IL2RG gene, are highly susceptible to severe infections. If untreated, the disease is fatal, usually within the first year or two of life. Infants with X-SCID typically are treated with transplants of blood-forming stem cells, ideally from a genetically matched sibling. However, fewer than 20 percent of infants with the disease have such a donor. Those without a matched sibling typically receive transplants from a parent or other donor, which are lifesaving, but often only partially restore immunity. 

“A diagnosis of X-linked severe combined immunodeficiency can be traumatic for families,” said NIAID director Dr. Anthony Fauci. “These exciting new results suggest that gene therapy may be an effective treatment option for infants with this extremely serious condition, particularly those who lack an optimal donor for stem cell transplant. This advance offers them the hope of developing a wholly functional immune system and the chance to live a full, healthy life.”