Dataset Information

Stability and Reproducibility Underscore Utility of RT-QuIC for Diagnosis of Creutzfeldt-Jakob Disease.

ABSTRACT: Real-time quaking-induced conversion (RT-QuIC) allows the amplification of miniscule amounts of scrapie prion protein (PrP(Sc)). Recent studies applied the RT-QuIC methodology to cerebrospinal fluid (CSF) for diagnosing human prion diseases. However, to date, there has not been a formal multi-centre assessment of the reproducibility, validity and stability of RT-QuIC in this context, an indispensable step for establishment as a diagnostic test in clinical practice. In the present study, we analysed CSF from 110 prion disease patients and 400 control patients using the RT-QuIC method under various conditions. In addition, "blinded" ring trials between different participating sites were performed to estimate reproducibility. Using the previously established cut-off of 10,000 relative fluorescence units (rfu), we obtained a sensitivity of 85% and a specificity of 99%. The multi-centre inter-laboratory reproducibility of RT-QuIC revealed a Fleiss' kappa value of 0.83 (95% CI: 0.40-1.00) indicating an almost perfect agreement. Moreover, we investigated the impact of short-term CSF storage at different temperatures, long-term storage, repeated freezing and thawing cycles and the contamination of CSF with blood on the RT-QuIC seeding response. Our data indicated that the PrP(Sc) seed in CSF is stable to any type of storage condition but sensitive to contaminations with blood (>1250 erythrocytes/μL), which results in a false negative RT-QuIC response. Fresh blood-contaminated samples (3 days) can be rescued by removal of erythrocytes. The present study underlines the reproducibility and high stability of RT-QuIC across various CSF storage conditions with a remarkable sensitivity and specificity, suggesting RT-QuIC as an innovative and robust diagnostic method.

SUBMITTER: Cramm M

PROVIDER: S-EPMC4789202 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Fast, definitive diagnosis of Creutzfeldt-Jakob disease (CJD) is important in assessing patient care options and transmission risks. Real-time quaking-induced conversion (RT-QuIC) assays of cerebrospinal fluid (CSF) and nasal-brushing specimens are valuable in distinguishing CJD from non-CJD conditions but have required 2.5 to 5 days. Here, an improved RT-QuIC assay is described which identified positive CSF samples within 4 to 14 h with better analytical sensitivity. Moreover, analysis of 11 CJD patients demonstrated that while 7 were RT-QuIC positive using the previous conditions, 10 were positive using the new assay. In these and further analyses, a total of 46 of 48 CSF samples from sporadic CJD patients were positive, while all 39 non-CJD patients were negative, giving 95.8% diagnostic sensitivity and 100% specificity. This second-generation RT-QuIC assay markedly improved the speed and sensitivity of detecting prion seeds in CSF specimens from CJD patients. This should enhance prospects for rapid and accurate ante mortem CJD diagnosis. A long-standing problem in dealing with various neurodegenerative protein misfolding diseases is early and accurate diagnosis. This issue is particularly important with human prion diseases, such as CJD, because prions are deadly, transmissible, and unusually resistant to decontamination. The recently developed RT-QuIC test allows for highly sensitive and specific detection of CJD in human cerebrospinal fluid and is being broadly implemented as a key diagnostic tool. However, as currently applied, RT-QuIC takes 2.5 to 5 days and misses 11 to 23% of CJD cases. Now, we have markedly improved RT-QuIC analysis of human CSF such that CJD and non-CJD patients can be discriminated in a matter of hours rather than days with enhanced sensitivity. These improvements should allow for much faster, more accurate, and practical testing for CJD. In broader terms, our study provides a prototype for tests for misfolded protein aggregates that cause many important amyloid diseases, such as Alzheimer's, Parkinson's, and tauopathies.

Dataset Information

Stability and Reproducibility Underscore Utility of RT-QuIC for Diagnosis of Creutzfeldt-Jakob Disease.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets