PRENATAL THERAPY TRIED FOR IMMUNE-SYSTEM DISORDER.

Byline: Angela La Voie Knight-Ridder Tribune News Wire

Fetuses that have an immune-system disorder that would ultimately cause them to spend their lives in a ``bubble'' may benefit from an experimental technique that involves transplanting healthy immune cells from the parent to the fetus, researchers reported here Monday at the annual meeting of the American College of Obstetricians and Gynecologists.

So far, the technique appears to have worked in one infant and is being tried in another fetus, reported Dr. Mark Evans, professor and vice chairman of obstetrics and gynecology at Wayne State University in Detroit.

Both fetuses were found to have a condition known as severe combined immunodeficiency disease (SCID), in which the fetal immune system does not develop enough of certain infection-fighting cells known as T-cells, according to Evans. The condition is often fatal.

Infants born with SCID are known as ``bubble babies'' because they must be encased in a plastic bubble and breathe air from a tank to protect them from potentially lethal infections.

In the first case, the mother of the fetus had previously given birth to a boy who died from SCID at 7 months. So when she became pregnant again, she sought prenatal diagnosis to determine whether the new fetus also would inherit SCID.

Using a test known as chorionic villus sampling, the researchers confirmed that the fetus also would be born with SCID. So at 16 weeks gestation, the researchers extracted certain cells from the bone marrow of the father and then injected the cells into the fetal liver, where immune-system cells develop in fetuses, Evans said.

It is important to apply the technique early, he said, before the fetal immune system can reject the transplanted cells.

The fetus is now a healthy 2-year-old boy, according to Evans.

The researchers reported preliminary results last December in The New England Journal of Medicine. Since then, Evans said that the researchers have applied the technique in a second fetus at Children's Hospital in Philadelphia. However, they will not know whether the attempt was successful until the mother gives birth, he said.