Creutzfeldt-Jakob disease: diagnostic utility of 14-3-3 protein immunodetection in cerebrospinal fluid

With the aim of improving the pre-mortem diagnostic accuracy of sporadic Creutzfeldt-Jakob disease (CJD), there has been considerable recent interest in the merit of immunodetecting 14-3-3 proteins in the cerebrospinal fluid (CSF) using Western blotting, with cumulative support for the utility of this technique. As a corollary, during a 20 month period, CSF samples from an unselected prospective series of 124 patients in whom sporadic CJD was a differential diagnostic possibility were examined by the Australian Creutzfeldt-Jakob disease Registry (ACJDR) for the presence of 14-3-3 proteins. Follow up to achieve a final diagnosis or clinical outcome was successful in 119. For definite and probable sporadic CJD combined, a positive result was 91.4% sensitive, while the sensitivity for the pathologically verified group alone was 96.0%. A negative outcome was 92.5% specific with false positive results seen in five patients with diagnoses which included inflammatory CNS disorders, cerebral ischaemia and dementia with Lewy bodies (DLB). Immunodetectable 14-3-3 proteins were present in three of four symptomatic patients with prion protein gene (PRNP) mutations. CSF samples containing significant amounts of blood were confirmed as suboptimal, with weak or qualitatively unusual positive results found in greater than 50% of such specimens, with only one of 14 such cases ultimately classified as definite or probable CJD.