Research that will be published in today's edition of The New England Journal of Medicine gives hope to children born with complete DiGeorge Syndrome, a rare genetic disorder resulting in a missing thymus gland and a nonfunctional immune system.
Dr. Louise Markert, the lead investigator of the study and an associate professor of pediatric allergy and immunology, has found a way to use otherwise discarded thymus tissue from pediatric heart surgeries to reconstruct the gland.
The thymus is essential to the immune system-directing T cells that target infected or foreign cells. Markert's procedure allows those born with the syndrome to grow a thymus gland and have a functional immune system.
The procedure involves using several grams of thymus tissue that are routinely removed during heart surgery on babies less than three months old. This tissue is then sliced into thin pieces and allowed to sit in a culture until all the T cells are killed.
Once the tissue has been prepared, it is inserted into an infant's thigh muscles, where its blood vessels then can grow into the strips which constitute the thymus.
Markert added that the lack of a thymus gland in her patients alleviates concerns that the patient's body will reject the foreign tissue. "It's a pristine environment when it comes to tissue transplants," she said.
Dr. Laura Hale, assistant professor of pathology, has performed biopsies on thymus glands and said Markert's procedure is indeed a cure for complete DiGeorge Syndrome.
"One of the girls who received the transplant is now alive and, well, functioning like any normal human being," she said.
Although differing degrees of DiGeorge Syndrome affect almost one in 2,000 infants annually, only about five to 10 of these cases constitute complete DiGeorge Syndrome.
Because the syndrome is so rare, Markert had to work with patients across the country.
She said a $3 million grant from the National Institutes of Health allowed her patients to have beds at the Medical Center for the duration of the research.
"A patient who comes in for research needs to remain close by in case there are any complications," Markert explained.
Markert's research on complete DiGeorge Syndrome began in 1991, when a Tennessee family asked her to help their child who suffered from complete DiGeorge Syndrome.
"Really, what are you going to say to a baby?" Markert said. "You have to try to do something."
Researchers have been unsuccessfully attempting to cure complete DiGeorge Syndrome for more than 40 years.
Markert attributes her success to working with Dr. Barton Haynes, Frederic M. Hanes professor of medicine, and Dr. Rebecca Buckley, the J. Buren Sidbury professor of allergy and immunology.
She said that their guidance allowed her to focus a great deal of her work on slicing the tissue correctly and preserving its quality.
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