New Stanford blood test identifies heart-transplant rejection earlier than biopsy can

PUBLIC RELEASE DATE:

18-Jun-2014

Contact: Krista Conger kristac@stanford.edu 650-725-5371 Stanford University Medical Center

Stanford University researchers have devised a noninvasive way to detect heart-transplant rejection weeks or months earlier than previously possible. The test, which relies on the detection of increasing amounts of the donor's DNA in the blood of the recipient, does not require the removal of any heart tissue.

"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," said Stephen Quake, PhD, professor of bioengineering and of applied physics. "We believe it's likely to be very useful in the clinic."

Quake, the Lee Otterson Professor in the School of Engineering and a Howard Hughes Medical Institute investigator, is a senior author of the study, which will be published June 18 in Science Translational Medicine. Kiran Khush, MD, assistant professor of medicine, is the other senior author. Postdoctoral scholar Iwijn De Vlaminck, PhD, is the lead author.

The test, called a cell-free DNA test, is different from another blood test, AlloMap, used to detect rejection. The commercially available AlloMap uses a blood sample to analyze the expression of immune-system genes involved in rejection. The researchers found that the cell-free DNA test outperformed AlloMap by a substantial margin.

"We've found that this cell-free DNA assay is a very accurate way to diagnose acute rejection, sometimes weeks to months before a biopsy picks up any signs," Khush said. "This earlier detection may prevent irreversible damage to the transplanted organ."

Recipients with signs of rejection can be placed on anti-rejection medications to mitigate the immune system's attack. Sometimes, however, the rejection episode is too strong and a second transplant is required.

Currently, heart-transplant recipients undergo dozens of heart biopsies in the months and years after their transplant. During a biopsy, a small tube is threaded through the jugular vein in the neck, and a serrated pincer is used to pluck off small bits of heart tissue for analysis. The procedure is uncomfortable and may cause complications such as heart rhythm abnormalities or valve damage. It's also expensive and time-consuming, and delivers results that can be subjective or can vary according to the sampling location within the heart.

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New Stanford blood test identifies heart-transplant rejection earlier than biopsy can