A Test for Creutzfeldt–Jakob Disease Using Nasal Brushings

Abstract

BACKGROUND Definite diagnosis of sporadic Creutzfeldt–Jakob disease in living patients remains a challenge. A test that detects the specific marker for Creutzfeldt–Jakob disease, the prion protein (PrPCJD), by means of real-time quaking-induced conversion (RT-QuIC) testing of cerebrospinal fluid has a sensitivity of 80 to 90% for the diagnosis of sporadic Creutzfeldt–Jakob disease. We have assessed the accuracy of RT-QuIC analysis of nasal brushings from olfactory epithelium in diagnosing sporadic Creutzfeldt– Jakob disease in living patients. METHODS We collected olfactory epithelium brushings and cerebrospinal fluid samples from patients with and patients without sporadic Creutzfeldt–Jakob disease and tested them using RT-QuIC, an ultrasensitive, multiwell plate–based fluorescence assay involving PrPCJD-seeded polymerization of recombinant PrP into amyloid fibrils. RESULTS The RT-QuIC assays seeded with nasal brushings were positive in 30 of 31 patients with Creutzfeldt–Jakob disease (15 of 15 with definite sporadic Creutzfeldt–Jakob disease, 13 of 14 with probable sporadic Creutzfeldt–Jakob disease, and 2 of 2 with inherited Creutzfeldt–Jakob disease) but were negative in 43 of 43 patients without Creutzfeldt–Jakob disease, indicating a sensitivity of 97% (95% confidence interval [CI], 82 to 100) and specificity of 100% (95% CI, 90 to 100) for the detection of Creutzfeldt–Jakob disease. By comparison, testing of cerebrospinal fluid samples from the same group of patients had a sensitivity of 77% (95% CI, 57 to 89) and a specificity of 100% (95% CI, 90 to 100). Nasal brushings elicited stronger and faster RT-QuIC responses than cerebrospinal fluid (P<0.001 for the between-group comparison of strength of response). Individual brushings contained approximately 105 to 107 prion seeds, at concentrations several logs10 greater than in cerebrospinal fluid. CONCLUSIONS In this preliminary study, RT-QuIC testing of olfactory epithelium samples obtained from nasal brushings was accurate in diagnosing Creutzfeldt–Jakob disease and indicated substantial prion seeding activity lining the nasal vault. (Funded by the Intramural Research Program of the National Institute of Allergy and Infectious Diseases and others.)

Quantitative assessment of prion infectivity in tissues and body fluids by real-time quaking-induced conversion

“…The ASA and RT-QuIC are generally analogous to sPMCA, but employ recombinant PrP C instead of brain homogenate as substrate for disease-specific, in vitro, amyloid formation (Atarashi et al, 2007(Atarashi et al, , 2011aColby et al, 2007). RT-QuIC offers the advantage of real-time assessment of amyloid fibril generation and has been successfully applied to many seed sources, some of which are available for antemortem sampling (Atarashi et al, 2011a, b;Elder et al, 2013;Haley et al, 2013;Henderson et al, 2013;McGuire et al, 2012;Orrú et al, 2011Orrú et al, , 2014Peden et al, 2011;Sano et al, 2013;Wilham et al, 2010).…”

A rare case of rapidly progressive dementia with elevated RT-QuIC and negative 14-3-3 and tau proteins

“…PrP-CJD is also the main component of the infectious CJD agent and propagates itself by seeding or templating the assembly of PrPC into misfolded multimers that can take the form of amyloid fibrils. 6 Although PrP-CJD was identified as the marker for CJD, it was difficult to identify a PrP-CJD assay and a non-invasive method of obtaining a tissue from living subjects that was adequately ELEVATED RT-QUIC WITH NEGATIVE 14-3-3 AND TAU PROTEINSsensitive. CSF testing with a new in vitro PrP-CJD amplification technology, a designated real-time quaking-induced conversion (RT-QuIC) has recently been identified as a highly specific diagnostic test for sCJD.…”

Sporadic and Infectious Human Prion Diseases

“…3) (McGuire et al 2012). Olfactory mucosa biopsy combined with RT-QuIC has a similar utility, but requires expertise to obtain appropriate specimens (Orrú et al 2014).…”