Real time quaking‐induced conversion analysis of cerebrospinal fluid in sporadic Creutzfeldt–Jakob disease

Abstract

Objective: Current 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. Methods: An 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). Results: The 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. Interpretation: This study shows that CSF RT‐QuIC analysis has the potential to be a more specific diagnostic test for sCJD than current CSF tests. ANN NEUROL 2012;72:278–285.

Cerebrospinal fluid real‐time quaking‐induced conversion is a robust and reliable test for sporadic creutzfeldt–jakob disease: An international study

“…Most laboratories used either a BMG LABTECH Optima or a BMG LABTECH Omega, whereas 1 laboratory used a Tecan Infinite F200PRO (Tecan Group, Männedorf, Switzerland). Nine laboratories used hamster full‐length (23–231) rPrP (supplied by Bristol Institute of Blood Sciences, Bristol, UK),8, 9 2 used human full‐length (23–231) rPrP (produced in‐house),7 and 1 used a hamster–sheep chimeric rPrP (hamster 14–126 residues followed by sheep residues 141‐234, produced according to previously reported conditions) 5…”

“…Shaking performed in a Thermomixer Comfort (Eppendorf, Hamburg, Germany) before being read in an Optima instrument.CSF = cerebrospinal fluid; Ham FL = hamster full‐length PrP (23–231)8, 9; Ham‐Sh chimeric = hamster residues 14–128 :sheep 141–234 5; Hum FL = human full‐length (23–231)—codon 129M6; PrP = prion protein; rfu = relative fluorescence units.…”

“…CSF RT‐QuIC has been shown to be an accurate diagnostic test for sCJD, with a high degree of sensitivity (85–87%) and specificity (99–100%) 7, 8. An increasing number of laboratories have established RT‐QuIC analysis, and more are interested in doing so.…”

Alpha‐synuclein RT‐QuIC in the CSF of patients with alpha‐synucleinopathies

“…Indeed, there is much discussion in current literature as to whether the alpha‐synucleinopathies are actually prion‐like diseases 11. A recently described technique called real‐time quaking‐induced conversion (RT‐QuIC), which exploits the ability of prion protein to induce self‐aggregation, has been used to develop a diagnostic CSF test for sporadic Creutzfeldt–Jakob disease (sCJD), the most common human form of TSE 12. Using our expertize in RT‐QuIC,12 we have developed and tested a similar assay for the detection of a‐syn in CSF.…”

A new diagnostic test for Creutzfeldt-Jakob disease: Real-time quaking-induced conversion (RT-QuIC)

“…However, ongoing validation studies have demonstrated that the outcomes of RT-QuIC reactions depend on the exact conditions employed (biochemical, chemical and physical), as well as the nature of the sample and recombinant substrate. The protocol under evaluation by the National Microbiology Laboratory has been tested extensively for the detection of sporadic CJD (10,11,15,16 ). Using this protocol the Prion Laboratory Section achieved 100% sensitivity and 100% specificity in the evaluation of an external sporadic CJD infected CSF proficiency panel.…”