A new technique that combines an immune-suppressing drug with a transplant can save the lives of otherwise doomed babies with a rare genetic disorder, U.S. doctors reported on Tuesday.

The new technique has rescued five of six infants with complete DiGeorge Syndrome, the team at Duke University Medical Center reported.

Babies with complete DiGeorge Syndrome have no thymus, the gland that helps in the production of immune cells called T-cells. T-cells attack invaders such as viruses or bacteria, but have to be “educated” in the thymus to work correctly.

Without a working thymus, babies with DiGeorge syndrome quickly succumb to infections and die by the age of 2.

A piece of thymus can be transplanted but in some babies the transplant is rejected. The transplants come from other babies getting cardiac surgery.

Writing in an upcoming issue of the journal Blood, pediatrician Dr. Louise Markert and colleagues said they used a drug to temporarily suppress the immune response before the transplant, allowing it time to take hold and begin to work.

They tried the new method on six babies. Five of them have lived for between 15 and 30 months, while one died of a respiratory infection, Markert reported.

The five survivors were immunized against tetanus and showed a normal immune response, the researchers said.

“It’s still experimental, but right now it’s the best option,” she said in a statement.

The thymus tissue transplant should be done within three months after birth, Markert said. “The key thing is to get it done before infections develop,” she said.

Complete DiGeorge syndrome is very rare, affecting between five and 10 children a year in the United States. Less serious forms of the genetic defect are seen in about one in every 4,000 births.