Blood Test Detects Prions of Creutzfeldt-Jakob Disease

The detection of prions in the blood of patients with variant Creutzfeldt-Jakob disease could lead to a noninvasive diagnosis prior to symptoms and a way to identify prion contamination of the donated blood supply.

Human prion diseases are infectious and invariably fatal neurodegenerative diseases. They include sporadic Creutzfeldt-Jakob disease (sCJD), the most common form, and variant Creutzfeldt-Jakob disease (vCJD), which is caused by the transmission of bovine spongiform encephalopathy, commonly known as mad cow disease, from infected cattle to humans.

The disease can lay silent in the body for decades as damage slowly builds in the brain from the misfolded infectious proteins called prions. On average, people infected with vCJD die two years after the development of the first symptoms, which can include psychiatric alterations such as depression, anxiety and hallucinations that progress to more severe dementia, muscle contractions and loss of coordination.

Scientists at the University of Texas Health Science Center (Houston, TX, USA) developed a biochemical assay for the sensitive, specific, early, and noninvasive detection of prions (PrPSc) in the blood of patients affected by prion disease, which is a top medical priority to increase the safety of the blood supply. They used the protein misfolding cyclic amplification (PMCA) technique to analyze blood samples from 14 cases of vCJD and 153 controls, including patients affected by sCJD and other neurodegenerative or neurological disorders as well as healthy subjects.

The team showed that PrPSc could be detected with 100% sensitivity and specificity in blood samples from vCJD patients. Detection was possible in any of the blood fractions analyzed and could be done with as little as a few microliters of sample volume. The PrPSc concentration in blood was estimated to be ~0.5 pg/mL. The findings suggest that PMCA may be useful for premortem noninvasive diagnosis of vCJD and to identify prion contamination of the blood supply. The study was published on December 21, 2016, in the journal Science Translational Medicine.

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University of Texas Health Science Center