Scientists from the University of Melbourne (UM) in Australia have reported a breakthrough in the creation of a blood test for variant Creutzfeldt-Jakob disease (vCJD), the human form of “mad cow disease” (bovine spongiform encephalopathy, BSE). They discovered that cells infected with vCJD release particles with “signature genes” that are not produced by healthy cells. These findings could lead to the creation of a commercially available test within five years.
A report of the discovery, “Small RNA Deep Sequencing Reveals a Distinct miRNA Signature Released in Exosomes from Prion-Infected Neuronal Cells,” was published online September 10, 2012, in Nucleic Acids Research. The lead author of the report is Andrew F. Hill, PhD, Professor in the Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute and Mental Health Research Institute at UM.
vCJD is characterized by misshapen prion proteins that form spongelike holes in the brain tissue. The condition is degenerative and results in death. The majority of vCJD cases in humans occurred during an outbreak in the United Kingdom (UK) in the 1990s, after people ate beef contaminated with BSE. There have been 170 confirmed fatal cases of vCJD in the UK.
Transmissions of vCJD via transfusions containing contaminated blood or blood products are also a growing concern. There have been five transfusion-related cases in the UK. The problem for health officials has been the lack of an available diagnostic test for vCJD (the disease can only be confirmed via a post-mortem brain matter analysis) and the virus’s dormancy period, which can last for years or even decades before symptoms appear.
Scientists and health officials recognize the benefits of a test. “This might provide a way to screen people who have spent time in the UK, who currently face restrictions on their ability to donate blood,” explained Hill. “With a simple blood test nurses could deem a prospective donor’s blood as healthy, with the potential to significantly boost critical blood stocks.”
Hill and his colleagues at UM are targeting cells that have been infected with the malformed prions, which are the source of vCJD. These cells, which travel in the bloodstream, disperse particles known as exosomes that include identifiable “signature genes” called microRNAs. The ability to detect these genetic signatures in the blood is the basis of the test.
Source: ABC Rural and news release from the University of Melbourne, September 12, 2012