(Press-News.org) Hercules, CA — August 27, 2013 — A recently reported blood test for the early detection of organ transplant injury could enable more timely therapeutic intervention in transplant patients and thus help to avoid longer term damage. As described by scientists at the University Medical Center Göttingen and Chronix Biomedical, a molecular diagnostics company, the new method uses Bio-Rad Laboratories' Droplet Digital PCR (ddPCR™) technology to overcome the obstacles of earlier tests, which were both time-consuming and costly. The method was presented at the American Association of Clinical Chemistry (AACC) 2013 annual meeting and has been accepted for publication in Clinical Chemistry.
Approximately 28,000 organ transplantations (known as grafts) are performed each year in the U.S., with another 100,000 patients on waiting lists. However, transplant patients are often subject to organ rejection: acute rejection of liver transplants within three years is nearly 22 percent, while heart and lung rejection is close to 50 percent. In addition, nearly half of all of kidney transplants fail within 10 years.
Graft-derived cell-free DNA (GcfDNA) in the circulation of transplant recipients is a potential rejection biomarker. But previous attempts to determine GcfDNA, which require parallel sequencing of donor and recipient DNA, are expensive and require a long turnaround and use of donor DNA. University Medical Center Göttingen and Chronix Biomedical researchers sought to develop a new method in an attempt to address these drawbacks.
Using ddPCR for Fast, Cost-Effective Test
The researchers applied Bio-Rad's ddPCR technology to quantify graft-derived cfDNA in recent liver transplant patients and in stable patients who had undergone a transplant procedure more than six months earlier. ddPCR technology allowed them to develop a cost-effective and fast laboratory test that detects cfDNA being released into the blood stream by dying cells from the transplanted organ.
"GcfDNA from dying graft cells are the most direct and sensitive indicator of organ rejection and we needed an instrument that could measure it," said Chronix Biomedical's Chief Technology Officer and the study's senior author, Ekkehard Schuetz, MD, PhD. "ddPCR added an additional level of reliability and precision to traditional PCR."
Sequencing methods typically require batch sampling, but by using ddPCR, researchers are able to run single samples. Additionally, this method is reducing test time from three days or more to one day and costs by 90 percent. The study authors were able to address the need for donor DNA by preselecting SNPs that ensure enough heterogeneity between donor and recipient. The new blood test can also deliver results up to several days before the conventional aspartate aminotransferase (AST) and bilirubin tests for liver transplantation rejection, with the potential for an immediate positive impact on patient care.
"We will now be able to detect subclinical rejection and early intervention may allow us to avoid a full-blown rejection," said Michael Oellerich, M.D., FACB, FRCPath and Lower Saxony Distinguished Professor of Clinical Chemistry at the University Medical Center Göttingen and study Principal Investigator. "This test may be useful to personalize immunosuppression and to improve long-term outcomes."
"Detecting non-host cfDNA is the third example for the commercial potential of cfDNA diagnostics. Researchers will now be able to extend the applications from fetal cfDNA in maternal blood and personalized biomarkers for minimal residual disease in cancer to solid organ transplantation," said Howard Urnovitz, PhD, Chronix Biomedical's Chief Executive Officer.
"We are looking forward to the improvements in precision medicine we can offer with ddPCR and this example in transplantation highlights the diagnostic value for the technology," said Paula Stonemetz, Director Diagnostic Business Development, Digital Biology Center, Bio-Rad Laboratories.
The researchers were awarded a National Academy of Clinical Biochemistry (NACB) Distinguished Abstract Award at the 2013 AACC annual conference. The results are part of a larger planned study to determine if cfDNA is the earliest indication of a transplant organ rejection.
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About Bio-Rad
Bio-Rad Laboratories, Inc. (NYSE: BIO and BIOb) has been at the center of scientific discovery for 60 years, manufacturing and distributing a broad range of products for life science research and clinical diagnostic markets. The company is renowned
for its commitment to quality and customer service among university and research institutions, hospitals, public health and commercial laboratories, as well as the biotechnology, pharmaceutical, and food safety industries. Founded in 1952, Bio-Rad is based in Hercules, California, and serves more than 100,000 research and industry customers through its global network of operations. The company employs approximately 7,600 people worldwide and had revenues exceeding $2 billion in 2012. Visit us at http://www.bio-rad.com.
This release contains certain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and Section 21E of the Securities Exchange Act of 1934. Forward-looking statements generally can be identified by the use of forward-looking terminology such as, "believe," "expect," "may," "will," "intend," "estimate," "continue," or similar expressions or the negative of those terms or expressions. Such statements involve risks and uncertainties, which could cause actual results to vary materially from those expressed in or indicated by the forward-looking statements. For further information regarding the Company's risks and uncertainties, please refer to the "Risk Factors" in the Company's public reports filed with the Securities and Exchange Commission, including the Company's most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. The Company cautions you not to place undue reliance on forward-looking statements, which reflect an analysis only and speak only as of the date hereof. Bio-Rad Laboratories, Inc., disclaims any obligation to update these forward-looking statements.
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