Patrick Yang ’20
Variant Creutzfeldt-Jakob disease (vCJD), commonly known as the human form of mad cow disease, is a neurodegenerative condition that is transmitted from infected cattle to humans. The disease’s long incubation stage allows for an asymptomatic period when prions, or infectious proteins, multiply in the brain with no sign of infection. On average, infected individuals die one to two years after onset of first symptoms. But currently, there is no validated test or cure for the fatal disease. The prevalence of asymptomatic carriers in the population, especially without a test to identify affected individuals, risks further infection of the blood-borne condition.
In a recent study led by Dr. Claudio Soto at The University of Texas Health Science Center, a diagnostic test for vCJD was developed. The two-step process involved a bead capture step in which magnetic nanobeads bound themselves to infectious agents within a small sample of plasma. In order to confirm the presence of vCJD in such a small sample, infectious agent concentration was amplified through a process called “protein misfolding cyclic amplification.” To validate the sensitivity of the test, Soto and his team blindly analyzed 149 plasma samples from French and British patients: 14 vCJD-infected individuals, 86 patients with other neurological diseases, and 49 healthy individuals. Among the 149 plasma samples, only the 14 vCJD-infected individuals were identified for vCJD, indicating a diagnostic sensitivity of 100%.
The development of a diagnostic blood assay for vCJD means that precautions can be taken to prevent the spread of the disease. Early diagnosis would allow infected individuals to receive proper care to slow neurodegeneration and the escalation of symptoms. The vCJD test itself was minimally invasive – it required a minimum blood volume of only 0.37 microliters. Although further research will need to be done to validate the test for use in a clinical setting, the ability to diagnose vCJD is a substantial step forward.
- C. Soto, et al., Detection of prions in blood from patients with variant creutzfeldt-jakob disease. Science Translational Medicine 8, (2016). doi: 10.1126/scitranslmed.aaf6188.
- Image retrieved from: https://simple.wikipedia.org/wiki/Prion#/media/File:Histology_bse.jpg