Hope for Babies Born Without Immune Systems

Thymus transplant helps them generate T-cells, study says

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THURSDAY, July 31, 2003 (HealthDayNews) -- Using an experimental transplantation procedure, Duke University Medical Center doctors successfully treated seven of 12 children born without a thymus, the organ that generates immune cells.

The research, published in the Aug. 1 issue of Blood, demonstrates that transplanting thymus tissue normally discarded during cardiac surgery on other infants can save the lives of children without a thymus.

The absence of a thymus, known as complete DiGeorge Syndrome, means a baby's immune system can't develop. The thymus "trains" cells to become T-cells, white blood cells that fight infection. Since children without a thymus don't produce T-cells, they're at great risk for developing infections.

Without medical intervention, few children with complete DiGeorge Syndrome live to age 1 and none live past age 3. Between 5 and 10 babies with complete DiGeorge Syndrome are born in the United States each year.

"Implanting thymus tissue early enough in life can provide these children with a chance to create a new immune system," lead author Dr. Louise Markert, an associate professor of pediatrics, says in a news release.

This study included 12 children with complete DiGeorge Syndrome who had the experimental thymus transplant at Duke University Medical Center between 1993 and 2001. Duke is the only facility in the world that does the procedure.

The thymus rests on the heart. During neonatal heart surgeries, a small amount of thymus tissue is normally discarded. That's because surgeons have to cut through it to expose the heart.

This discarded thymus tissue is prepared and tested for any abnormalities or diseases before it's used for transplant. Thin slices of the thymus tissue are implanted in the quadriceps muscles of both legs in babies with complete DiGeorge Syndrome.

It isn't necessary to match donor tissue with the recipient. Since babies with complete DiGeorge Syndrome don't have an immune system, they can't reject new organs.

The seven surviving thymus transplant children are all well and living at home two to 10 years after having the procedure. The other five children in the study died, all from underlying congenital problems, the study says.

More information

Here's where you can learn more about the immune system.

SOURCE: Duke University, news release, July 24, 2003
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