Real-time quaking-induced conversion analysis for the diagnosis of sporadic creutzfeldt-jakob disease in Korea

Abstract

Background and PurposezzThe level of 14-3-3 protein in the cerebrospinal fluid (CSF) is increased in Creutzfeldt-Jakob disease (CJD) patients, which has led to it being used as a clinical biomarker for the ante-mortem diagnosis of human prion diseases. However, the specificity of the 14-3-3 protein is less reliable for CJD diagnosis. Newly developed assays in-cluding real-time quaking-induced conversion (RT-QuIC) have made it possible to detect the PrPSc-like abnormal prion isoform with a high sensitivity in animal and human specimens that might contain a minute amount of PrPSc due to in vitro prion replication. MethodszzThis study applied a highly sensitive RT-QuIC assay using recombinant human PrP to detect PrPSc in the CSF of 81 patients with sporadic CJD (sCJD) in Korea. ResultszzRT-QuIC analysis of the CSF samples based on the expression levels of 14-3-3 and total tau proteins revealed positivity in 62 of 81 sCJD patients (sensitivity of 76.5%) but no positive results in the 100 non-CJD patients. ConclusionszzThe sensitivity of the RT-QuIC in this study was similar to that in some pre-vious reports, and the specificity of RT-QuIC was higher than that of 14-3-3 in CSF, suggest-ing that RT-QuIC analysis can complement the weakness of the specificity of 14-3-3 for the diagnosis of sCJD. These results indicate that RT-QuIC might be very useful for the rapid and specific diagnosis of sCJD and provide a practical novel method for the ante-mortem diagno- sis of human prion diseases.