New Blood Test May Help Detect Heart Transplant Rejection

WEDNESDAY, June 18, 2014 (HealthDay News) -- Researchers say they've developed a blood test that can detect heart transplant rejection weeks or months earlier than previously possible.

The test looks for increasing amounts of the heart donor's DNA in the blood of the transplant recipient. Unlike a biopsy, this noninvasive test does not require removal of any heart tissue, Stanford University researchers said.

"This test appears to be safer, cheaper and more accurate than a heart biopsy, which is the current gold standard to detect and monitor heart-transplant rejection," study co-senior author Stephen Quake, professor of bioengineering and applied physics, said in a university news release. "We believe it's likely to be very useful in the clinic."

Transplant recipients who show early signs of rejection can be given anti-rejection drugs in an effort to reduce the immune system's attack on the transplanted organ.

Currently, heart transplant patients have to undergo dozens of heart biopsies in the months and years after they receive their new heart. The biopsies are uncomfortable and may cause complications such as heart rhythm problems or heart valve damage, the researchers said.

The new test -- called a cell-free DNA test -- proved effective in a study of 44 adults and 21 children who had heart transplants. The test accurately detected rejection in 24 patients who suffered moderate to severe rejection, including one who required a second heart transplant, the researchers said.

The test was able to detect signs of rejection up to five months before biopsies showed any signs of trouble, according to the study published June 18 in the journal Science Translational Medicine.

"We've found that this cell-free DNA [test] is a very accurate way to diagnose acute rejection, sometimes weeks to months before a biopsy picks up any signs," study co-senior author Dr. Kiran Khush, an assistant professor of medicine at Stanford, said in the news release. "This earlier detection may prevent irreversible damage to the transplanted organ."

The new test is different from another blood test used to detect transplant rejection. That test is called AlloMap and it checks for immune system genes involved in rejection. The cell-free DNA test outperformed AlloMap by a wide margin, according to the Stanford team.

The researchers noted that there's still a great deal of work to be done before this cell-free DNA test could become commercially available.

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New Blood Test May Help Detect Heart Transplant Rejection