Detection of pathologic prion protein in the olfactory epithelium in sporadic Creutzfeldt-Jakob disease

BACKGROUND: Olfactory cortexes and the olfactory tracts are involved in sporadic Creutzfeldt-Jakob disease. We examined peripheral regions of the olfactory sensory pathway, including the olfactory mucosa, to assess whether pathologic infectious prion protein (PrP(sup Sc)) is deposited in the epithelium lining the nasal cavity. METHODS: We studied nine patients with neuropathologically confirmed sporadic Creutzfeldt-Jakob disease. We obtained the brain, the cribriform plate with the attached olfactory mucosa, and the surrounding respiratory epithelium at autopsy. Control samples of nasal mucosa were obtained post mortem or at biopsy from age-matched control subjects and from control patients with other neurodegenerative diseases. The olfactory and respiratory mucosa and the intracranial olfactory system were analyzed by light microscopy, immunohistochemistry, and Western blotting for pathological changes and for deposition of PrP(sup Sc). RESULTS: In all nine patients with sporadic Creutzfeldt-Jakob disease, PrP(sup Sc) was found in the olfactory cilia and central olfactory pathway but not in the respiratory mucosa. No PrP(sup Sc) was detected in any of the tissue samples from the 11 controls. CONCLUSIONS: Our pathological and biochemical studies show that PrP(sup Sc) is deposited in the neuroepithelium of the olfactory mucosa in patients with sporadic Creutzfeldt-Jakob disease, indicating that olfactory biopsy may provide diagnostic information in living patients. The olfactory pathway may represent a route of infection and a means of spreading prions.