New Thymus Tissue Jump-Starts Immune System in Babies. (Transplant Hope)
Seppa, N., Science News
Babies born without a thymus gland--and therefore bereft of a functioning immune system--are easy prey for disease-causing invaders. If untreated, this deficiency, called severe DiGeorge syndrome, is invariably fatal before a child's third birthday.
For babies with the syndrome, also called DiGeorge anomaly, a thymus transplant may present a life-changing option. But scientific information on such transplants has been limited to the results of sporadic case studies because the disease is rare, affecting only a handful of newborns each year in the United States. Researchers at Duke University Medical Center in Durham, N.C., now report the largest series of thymus transplants--in 12 children with DiGeorge syndrome over 8 years--and show success in establishing an immune system in many of these babies. The report appears in the Aug. 1 issue of Blood.
The babies received transplanted thymus tissue within their first few months of life. The grafted tissue takes a long time to build up a protective army of white blood cells called T cells, says M. Louise Markert, a pediatric immunologist at Duke, so the children remained especially vulnerable to infections for months after the surgery.
White blood cells begin in the bone marrow. Some of these migrate to the thymus gland, which sits above the heart, and there become T cells. Named for the thymus gland, T cells are frontline defenders in the immune system and champs at distinguishing the body's own tissues from foreign materials.
For the transplants, doctors salvaged some thymus tissue that otherwise would have been discarded from children undergoing heart surgery. …