Testing of olfactory epithelium samples obtained from nasal brushing may be an accurate means of diagnosis for Creutzfeldt–Jakob disease (CJD), according to a new study funded by the National Institutes of Health (NIH). The research findings appear in the New England Journal of Medicine.
Prior to this study, a definitive CJD diagnosis required brain tissue testing post-mortem or via biopsy in living patients. Researchers from NIH and Italian colleagues collected olfactory epithelium brushings and cerebrospinal fluid samples from patients with and patients without sporadic Creutzfeldt–Jakob disease; these samples were then tested for the specific marker for CJD, the prion protein (PrPCJD). The real-time quaking-induced conversion (RT-QuIC) assays with samples from nasal brushing were positive in 30 out of 31 patients with CJD and were negative in all of the patients with CJD, indicating a sensitivity of 97% and specificity of 100%. Cerebrospinal samples from the same group of patients had a sensitivity of 77% and a specificity of 100%. The nasal brushing also contained a higher proportion of prion seeds at concentrations greater than in cerebrospinal fluid.
The researchers plan to continue to evaluate the test’s efficacy in diagnosing CJD and expand to testing for prion diseases in animals. They also plan to develop alternate an swabbing approache to replace the nasal brush.
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