Rare 'Bubble Boy Illness' probably healed with a new gene therapy

According to a new study, eight infants with a serious immune disorder, sometimes called "Bubble Boy's Disease", seem to have cured this disease through experimental gene therapy.

This disorder, officially called X-linked severe combined immunodeficiency (SCID-X1), gives birth to babies with little or no immune protection, thus making them more likely to develop life-threatening infections. This is caused by a specific genetic mutation.

The new gene therapy involves the use of a modified version of HIV – the virus that usually attacks the immune system and causes AIDS – to deliver a correct copy of the gene that causes the disease. (In this case, the virus was genetically modified so as not to cause disease.) [11 Surprising Facts About the Immune System]

According to the study published Wednesday (April 17) in the New England Journal of Medicine, all children now produce the immune cells needed to counter the barrage of germs that man encounters on a daily basis.

"These patients are now young children, who respond to vaccines and whose immune system allows them to [the] the immune cells they need to protect themselves from infections as they explore the world and lead a normal life, "said Dr. Ewelina Mamcarz, lead author of the study, hematologist-pediatric oncologist at the transplantation department of Bone marrow and cell therapy from St. Jude in Memphis, Tennessee, said in a statement.

Approximately 16 months after treatment, patients are progressing normally and have not experienced any serious side effects of treatment. But they will still need to be monitored for a longer period to determine if the treatment is sustainable and does not cause side effects later in life, the researchers said.

"Bubble Boy"

SCID-X1 is caused by a mutation in a gene called IL2RG, which is essential for normal immune function, according to the National Institutes of Health. The disease is rare and probably affects one in 50,000 to 100,000 newborns.

The disease can be essentially cured by a bone marrow transplant from a brother or sister that matches some immune system proteins. But less than 20% of patients with SCID-X1 have such a donor available, the authors said. Bone marrow transplants from unrelated donors are generally less effective and carry higher risks.

The name "bubble boy disease" comes from the highly publicized case of David Vetter, born in 1971 with SCID-X1, who has spent most of his life in a plastic bubble waiting for a bone marrow transplant, according to CBS. He died at the age of 12 after receiving his transplant.

Previous attempts to treat SCID-X1 by gene therapy have had serious side effects. For example, gene therapy therapy in the early 2000s resulted in the development of leukemia in several patients.

In the new study, researchers first collected bone marrow from patients. Next, they used the modified version of HIV to insert a working copy of the IL2RG gene into bone marrow cells. These cells were then reinjected to the patients. Prior to this infusion, patients received a low dose of a chemotherapy drug to help leave room in their bone marrow for new cell growth.

One of the concerns of gene therapy is that after the insertion of a gene into a person's DNA, the genes near the insertion site may become cancerous, as was the case in some cases. previous leukemia. But the new treatment has avoided this problem by including "insulating" genes that essentially block the activation of adjacent genes to prevent them from becoming cancerous.

The researchers say their technique could serve as a model for developing gene therapies for other blood disorders, such as sickle cell disease.

Originally published on Science live.