New Test for Heart, Kidney Transplant Rejection

THURSDAY, Sept. 23, 2010 (HealthDay News) -- A new blood test may offer a quicker, noninvasive way to detect organ rejection in heart and kidney transplant patients before the new organs are damaged, say researchers from the Stanford School of Medicine in California.

They found that levels of three easily measured proteins rise in the blood during acute rejection, in which a transplant patient's immune system attacks the new organ. This is the first study to pinpoint a rejection signal that's shared by two kinds of transplanted organs, according to the researchers.

The study appears online Sept. 23 in the journal PLoS Computational Biology.

Tests are now being conducted to determine if these protein signals can also be used to identify organ rejection in liver and lung transplant patients, the researchers added.

"In the past, we couldn't spot rejection episodes until they harmed the organ. Our goal is to develop blood tests that will keep transplanted organs functioning so that patients can avoid a second transplant," study co-senior author Dr. Atul Butte, an associate professor of medical informatics and of pediatrics, said in a Stanford news release.

About 40 percent of heart recipients and 25 percent of kidney recipients have an episode of acute rejection during the first year after transplant.

The new blood test could replace the current invasive, expensive and slow method, which involves monitoring the functioning of the new organ. If doctors detect a decline in function, they take a tiny sample from the transplanted organ to check for rejection. Based on what they find, they may adjust the patient's immune-suppressing drug regimen.

In addition to providing early warning about organ rejection, the new blood test could be used to identify transplant patients whose new organs are being well accepted by the body. Doctors could lower doses of immune-suppressing drugs in these patients, which would reduce unwanted drug side effects, the researchers noted.

To develop their blood test, the Stanford team utilized an existing method to detect proteins in blood -- enzyme-linked immunosorbent assay (ELISA) -- which is used to diagnose diseases such as strep throat.

The new organ rejection blood test could be commercially available in three to five years, Butte predicted.

More information

The American Society of Transplantation has more about staying healthy after a transplant.