Gene Therapy May Help Restore Immunity In Patients With Rare Immunodeficiency SCID-X1


Older kids and younger adults suffering from X-linked severe combined immunodeficiency, which is rare, could benefit from stem cell gene therapy, according to findings from an ongoing study.

The National Institute of Allergy and Infectious Diseases, backed by St. Jude Children’s Research Hospital, has been studying immunodeficiency SCID-X1, or X-linked SCID (severe combined immunodeficiency). The researchers recently found that gene therapy can rebuild the immune systems of young people who suffer from X-linked SCID.

X-linked SCID has also been referred to as “bubble boy disease,” because the condition primarily affects males and those affected by it have little or no defenses against certain, generally common, fungi, bacteria and viruses.

X-linked SCID comes from a mutation in the IL2RG gene, which is responsible for describing the details of a protein that’s vital to a fully functioning immune system. And since it’s supposed to relay the blueprints for that protein, its failure to do so can stunt the development of a person’s immune system.

But the National Institute of Allergy and Infectious Diseases may have found a way to build up immune systems hobbled by X-linked SCID.

Expanding on stem cell treatments given to infants with X-linked SCID, who typically require lifelong therapy, the researchers combined chemo and lentiviral gene therapy to five people, aged 7 to 24, who all suffered from the condition.

The researchers took stem cells from each of the study participants and infused them with lentiviruses, a sub genus of the retrovirus family. Retroviruses essentially rewrite bits of DNA and RNA in cells, and lentiviruses can even do so in non-dividing cells.

After a low dose of chemo, the repaired IL2RG cells were given back to each participant.

Researchers observed “substantial improvement” in the “immunity and clinical status” of the two first participants, with one of them still improving three years later. The second patient has been improving for two years after receiving the therapy, but died of pre-existing lung damage that was caused by an infection.

“The three other patients received the therapy three to six months ago and are beginning to show improvements in immune function,” says the National Institute of Allergy and Infectious Diseases. “Researchers are continuing to monitor the surviving patients.”