ThermoMixer-Aided Endpoint Quaking-Induced Conversion (EP-QuIC) Permits Faster Sporadic Creutzfeldt-Jakob Disease (sCJD) Identification than Real-Time Quaking-Induced Conversion (RT-QuIC).
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ABSTRACT:
SUBMITTER: Vendramelli R
PROVIDER: S-EPMC6018336 | biostudies-literature | 2018 Jul
REPOSITORIES: biostudies-literature
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ThermoMixer-Aided Endpoint Quaking-Induced Conversion (EP-QuIC) Permits Faster Sporadic Creutzfeldt-Jakob Disease (sCJD) Identification than Real-Time Quaking-Induced Conversion (RT-QuIC).
Vendramelli Robert R Sloan Angela A Simon Sharon L R SLR Godal Debra D Cheng Keding K
Journal of clinical microbiology 20180625 7
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Project description:BackgroundEvaluation of the application of CSF real-time quaking-induced conversion in Creutzfeldt-Jakob disease surveillance to investigate test accuracy, influencing factors, and associations with disease incidence.MethodsIn a prospective surveillance study, CSF real-time quaking-induced conversion was performed in patients with clinical suspicion of prion disease (2014-2022). Clinically or histochemically characterized patients with sporadic Creutzfeldt-Jakob disease (n = 888) and patients with final diagnosis of non-prion disease (n = 371) were included for accuracy and association studies.ResultsThe overall test sensitivity for sporadic Creutzfeldt-Jakob disease was 90% and the specificity 99%. Lower sensitivity was associated with early disease stage (p = 0.029) and longer survival (p < 0.001). The frequency of false positives was significantly higher in patients with inflammatory CNS diseases (3.7%) than in other diagnoses (0.4%, p = 0.027). The incidence increased from 1.7 per million person-years (2006-2017) to 2.0 after the test was added to diagnostic the criteria (2018-2021).ConclusionWe validated high diagnostic accuracy of CSF real-time quaking-induced conversion but identified inflammatory brain disease as a potential source of (rare) false-positive results, indicating thorough consideration of this condition in the differential diagnosis of Creutzfeldt-Jakob disease. The surveillance improved after amendment of the diagnostic criteria, whereas the incidence showed no suggestive alterations during the COVID-19 pandemic.
| S-EPMC9829526 | biostudies-literature
Project description:ObjectiveCurrent cerebrospinal fluid (CSF) tests for sporadic Creutzfeldt-Jakob disease (sCJD) are based on the detection of surrogate markers of neuronal damage such as CSF 14-3-3, which are not specific for sCJD. A number of prion protein conversion assays have been developed, including real time quaking-induced conversion (RT-QuIC). The objective of this study is to investigate whether CSF RT-QuIC analysis could be used as a diagnostic test in sCJD.MethodsAn exploratory study was undertaken that analyzed 108 CSF samples from patients with neuropathologically confirmed sCJD or from control patients. Of the 108 CSF samples, 56 were from sCJD patients (30 female, 26 male; aged 31-84 years; mean age, 62.3 ± 13.5 years), and 52 were from control patients (26 female, 26 male; aged 43-84 years; mean age, 67.8 ± 10.4 years). A confirmatory group of 118 patients was subsequently examined that consisted of 67 cases of neuropathologically confirmed sCJD (33 female, 34 male; aged 39-82 years; mean age, 67.5 ± 9.0 years) and 51 control cases (26 female, 25 male; aged 36-87 years; mean age, 63.5 ± 11.6 years).ResultsThe exploratory study showed that RT-QuIC analysis had a sensitivity of 91% and a specificity of 98% for the diagnosis of sCJD. These results were confirmed in the confirmatory study, which showed that CSF RT-QuIC analysis had a sensitivity and specificity of 87% and 100%, respectively.InterpretationThis study shows that CSF RT-QuIC analysis has the potential to be a more specific diagnostic test for sCJD than current CSF tests.
| S-EPMC3458796 | biostudies-literature
Project description:A 68-year-old man presented with a three-week history of rapidly progressive dementia, gait ataxia and myoclonus. Subsequent electroencephalography showed periodic sharp wave complexes, and cerebrospinal fluid assay revealed the presence of a 14-3-3 protein. A probable diagnosis of sporadic Creutzfeldt-Jakob disease was made, which was further supported by magnetic resonance (MR) imaging of the brain showing asymmetric signal abnormality in the cerebral cortices and basal ganglia. The aetiology, clinical features, diagnostic criteria, various MR imaging patterns and radiologic differential diagnosis of sporadic Creutzfeldt-Jakob disease are discussed in this article.
| S-EPMC6301874 | biostudies-literature
Project description:Cerebrospinal fluid-based real-time quaking-induced conversion (CSF RT-QuIC) is currently the most prominent method for early detection of sporadic Creutzfeldt-Jakob disease (sCJD), the most common prion disease. CSF RT-QuIC delivers high sensitivity (>90%) and specificity (100%), which has been demonstrated by large ring-trial studies testing probable and definitive sCJD cohorts. Following the inclusion of CSF RT-QuIC in the revised European CJD Surveillance Network diagnostic criteria for sCJD, it has become a standard diagnostic procedure in many prion disease reference or surveillance centers around the world. In this study, we present the implementation of the second-generation CSF RT-QuIC (commonly known as Improved QuIC or IQ) at the Danish Reference Center for Prion Diseases (DRCPD). The method's sensitivity and specificity were evaluated and validated by analyzing 63 CSF samples. These 63 samples were also analyzed at the National CJD Research and Surveillance Unit (NCJDRSU), based at the University of Edinburgh, UK; analysis was carried out using the first generation or previous CSF RT-QuIC method (PQ). The sensitivity and specificity of PQ during tests at the NCJDRSU were 92% and 100%, respectively. Using these 63 CSF samples, the agreement between the two RT-QuIC generations at DRCPD and NCJDRSU prion laboratories was 100%.
| S-EPMC10094695 | biostudies-literature
Project description:Background and purposeThe 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 including 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 PrP(Sc) due to in vitro prion replication.MethodsThis study applied a highly sensitive RT-QuIC assay using recombinant human PrP to detect PrP(Sc) in the CSF of 81 patients with sporadic CJD (sCJD) in Korea.ResultsRT-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.ConclusionsThe sensitivity of the RT-QuIC in this study was similar to that in some previous reports, and the specificity of RT-QuIC was higher than that of 14-3-3 in CSF, suggesting 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 diagnosis of human prion diseases.
| S-EPMC4712274 | biostudies-literature
Project description:Real-time quaking-induced conversion (RT-QuIC) is an assay in which disease-associated prion protein (PrP) initiates a rapid conformational transition in recombinant PrP (recPrP), resulting in the formation of amyloid that can be monitored in real time using the dye thioflavin T. It therefore has potential advantages over analogous cell-free PrP conversion assays such as protein misfolding cyclic amplification (PMCA). The QuIC assay and the related amyloid seeding assay have been developed largely using rodent-passaged sheep scrapie strains. Given the potential RT-QuIC has for Creutzfeldt-Jakob disease (CJD) research and human prion test development, this study characterized the behaviour of a range of CJD brain specimens with hamster and human recPrP in the RT-QuIC assay. The results showed that RT-QuIC is a rapid, sensitive and specific test for the form of abnormal PrP found in the most commonly occurring forms of sporadic CJD. The assay appeared to be largely independent of species-related sequence differences between human and hamster recPrP and of the methionine/valine polymorphism at codon 129 of the human PrP gene. However, with the same conditions and substrate, the assay was less efficient in detecting the abnormal PrP that characterizes variant CJD brain. Comparison of these QuIC results with those previously obtained using PMCA suggested that these two seemingly similar assays differ in important respects.
| S-EPMC3352348 | biostudies-literature
Project description:The Prion Laboratory Section of the Public Health Agency of Canada supports heath care professionals dealing with patients suspected to have Creutzfeldt-Jakob disease (CJD) by testing cerebrospinal fluid (CSF) for protein markers of CJD. To better serve Canadian diagnostic requirements, a quaking-induced conversion (QuIC)-based assay has been added to the test panel. The QuIC tests exploit the ability of disease-associated prion protein, found in the CSF of a majority of CJD patients, to convert a recombinant prion protein (rPrP) into detectable amounts of a misfolded, aggregated form of rPrP. The rPrP aggregates interact with a specific dye, causing a measurable change in the dye's fluorescence emission spectrum. Optimal test and analysis parameters were empirically determined. Taking both practical and performance considerations into account, an endpoint QuIC (EP-QuIC) configuration was chosen. EP-QuIC uses a thermo-mixer to perform the shaking necessary to produce the quaking-induced conversions. Fluorescence readings are obtained from a microwell fluorescence reader only at the beginning and the end of EP-QuIC reactions. Samples for which the relative fluorescence unit ratio between the initial and final readings represent a ≥4 increase in signal intensity in at least two of the three replicates are classified as positive. A retrospective analysis of 91 CSF samples that included 45 confirmed cases of CJD and 46 non-CJD cases was used to estimate the performance characteristics of the EP-QuIC assay. The diagnostic sensitivity and specificity of the EP-QuIC test of this set of samples were 98 and 91%, respectively.
| S-EPMC4922112 | biostudies-literature
Project description:Alu DNA elements were long considered to be of no biological significance and thus have been only poorly defined. However, in the past Alu DNA elements with well-defined nucleotide sequences have been suspected to contribute to disease, but the role of Alu DNA element transcripts has rarely been investigated. For the first time, we determined in a real-time approach Alu DNA element transcription in buffy coat cells isolated from the blood of humans suffering from sporadic Creutzfeldt-Jakob disease (sCJD) and other neurodegenerative disorders. The reverse transcribed Alu transcripts were amplified and their cDNA sequences were aligned to genomic regions best fitted to database genomic Alu DNA element sequences deposited in the UCSC and NCBI data bases. Our cloned Alu RNA/cDNA sequences were widely distributed in the human genome and preferably belonged to the "young" Alu Y family. We also observed that some RNA/cDNA clones could be aligned to several chromosomes because of the same degree of identity and score to resident genomic Alu DNA elements. These elements, called paralogues, have purportedly been recently generated by retrotransposition. Along with cases of sCJD we also included cases of dementia and Alzheimer disease (AD). Each group revealed a divergent pattern of transcribed Alu elements. Chromosome 2 was the most preferred site in sCJD cases, besides chromosome 17; in AD cases chromosome 11 was overrepresented whereas chromosomes 2, 3 and 17 were preferred active Alu loci in controls. Chromosomes 2, 12 and 17 gave rise to Alu transcripts in dementia cases. The detection of putative Alu paralogues widely differed depending on the disease. A detailed data search revealed that some cloned Alu transcripts originated from RNA polymerase III transcription since the genomic sites of their Alu elements were found between genes. Other Alu DNA elements could be located close to or within coding regions of genes. In general, our observations suggest that identification and genomic localization of active Alu DNA elements could be further developed as a surrogate marker for differential gene expression in disease. A sufficient number of cases are necessary for statistical significance before Alu DNA elements can be considered useful to differentiate neurodegenerative diseases from controls.
| S-EPMC2933056 | biostudies-literature
Project description:Real-Time Quaking-Induced Conversion (RT-QuIC) testing of human cerebrospinal fluid (CSF) is highly sensitive and specific in discriminating sporadic CJD patients from those without prion disease. Here, using CSF samples from 113 CJD and 64 non-prion disease patients, we provide the first direct and concurrent comparison of our improved RT-QuIC assay to our previous assay, which is similar to those commonly used internationally for CJD diagnosis. This extended comparison demonstrated a ~21% increase in diagnostic sensitivity, a 2-day reduction in average detection time, and 100% specificity.
| S-EPMC5288466 | biostudies-literature
Project description: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.
| S-EPMC4789202 | biostudies-literature