Contact: Kathryn Holleman
Want to avoid rejection? Try the internet if you’re looking for a soulmate. Try the Barnes-Jewish Hospital human leukocyte antigen (HLA) lab if you’re waiting for a transplant.
The transplant programs at Barnes-Jewish consistently post rejection rates among the lowest in the world, and Washington University transplant physicians often cite the work of the HLA lab as a contributing reason.
Tucked into a narrow hallway on the third floor of Barnes-Jewish south, the Barnes-Jewish HLA lab determines whether potential organ or tissue donors are good matches for waiting recipients. Test results, or crossmatches, are crucial to whether a transplant operation proceeds or not, says Donna Phelan, technical supervisor of the lab.
“Our technologists like to say, when people ask them what they do for a living, that they tell the doctors who they cannot transplant,” says Phelan.
The Barnes-Jewish HLA lab is well-regarded in the nation’s transplant community because of its combination of highly respected personnel, meticulous work and leadership in immunology research.
“There are only about 200 HLA labs in the country,” says Phelan. “We’re a small community, so we know about each other. I’m very proud of this lab. I’m very proud of this staff.”
With about 400 organ transplants and more than 300 bone marrow transplants performed at Barnes-Jewish each year, the staff of 13 HLA technologists is always busy, says Phelan.
The HLA lab identifies antigens in the blood and DNA samples of those on the waiting list for organ and bone marrow transplants and compares them to samples from potential donors.
Antigens are markers carried on the body’s cells. When the body’s immune system detects antigens it doesn’t recognize, it responds by producing antibodies -- proteins that attack the foreign substance.
In organ transplants, antigens in donor organs that are not recognized by the recipient’s body can trigger the recipient’s immune system to produce antibodies. This response, called rejection, can damage the donor organ. Uncontrolled acute rejection or chronic rejection can cause the transplant to fail.
While drugs can suppress the body’s immune response and prevent rejection, they can also leave the body vulnerable to infection. And immunosuppressant drugs themselves can be toxic.
So making sure donor and recipient antigens are as closely matched as possible lowers the likelihood of rejection and the level of immunosuppressants a transplant recipient must take.
Crossmatching tissue for organ transplants involves defining the antigens in the blood of both the recipient and potential donor. Cells from the donor and serum from the recipient are mixed together, and technologists then look to see if antibodies are produced.
“This in vitro test mimics what happens in the body,” said Phelan.
For bone marrow transplant the process is different. Since the recipient’s immune system is destroyed in preparation to receive donor stem cells, the donor tissue must be a perfect match or donor stem cells can actually attack the recipient’s tissue causing the potentially deadly “graft-versus-host disease.”
With bone marrow transplants, HLA technologists compare the DNA of the recipient and potential bone marrow donor. The HLA lab uses a technique called polymerase chain reaction (PCR) testing.
“It’s similar to the technique used in forensics,” Phelan said.
Timing is crucial in HLA testing. Final crossmatches – the last hurdle before a transplant operation begins – is done before surgery in a living donor transplant.
In the case of a deceased donor, a blood sample from the donor is shipped to the HLA lab as soon as possible after the donor’s death (brain or cardiac), and testing begins immediately upon its arrival. Even if the donor is at a different hospital and the blood sample has already been typed there, the Barnes-Jewish HLA lab will retype it to insure accuracy.
Potential bone marrow donors also are screened as rapidly as possible.
“These patients are usually very sick and need a transplant as quickly as possible,” said Phelan.
To accommodate the need for rapid testing around-the-clock, the lab is staffed 24 hours a day on weekdays and on call 24 hours a day on the weekend.
In addition, the lab regularly wins awards for its work and is known for its role in research. Phelan, who has authored more than 50 articles, and lab technical coordinator Brian Duffy, who also authors articles, often speak to groups around the country and internationally.
Phelan expects the lab to become even busier in the future, as new discoveries are made in transplant immunology, more Americans are added to transplant lists and as the Barnes-Jewish transplant programs continue to grow.
“In this field, there’s always something we can do better,” Phelan says. “There’s always something new happening here.”