Neurofilaments in blood and CSF for diagnosis and prediction of onset in Creutzfeldt-Jakob disease

While cerebrospinal fluid (CSF) biomarkers for Creutzfeldt-Jakob disease (CJD) are established and partly included in the diagnostic criteria, no blood biomarkers are available. Here, we assessed the utility of serum neurofilament light chain (NF-L) and tau protein in comparison to CSF markers (NF-L and phosphorylated NF heavy chain (pNF-H), tau, S100B, 14-3-3) and prion conversion assay (realtime quaking induced conversion (RT-QuIC)) for sporadic and genetic CJD. Importantly, a Gerstmann-Straussler-Scheinker mutation carrier in the asymptomatic phase and at disease onset was included as well. Both NF-L and tau were markedly increased in CJD serum, reaching similar or even better performance as in CSF (sensitivity and specificity for serum NF-L 100% and 85.5%, and for serum tau 84.6% and 96.2%, respectively). Serum S100B showed high sensitivity as well (84.2%), but lower specificity (63%). CSF neurofilaments were increased before symptom onset, while prion seeding assay was negative. Just before a clinical diagnosis could be made, all CSF markers and NF-L in the serum were increased and CSF prion conversion assay was positive. The data suggest that neurofilaments are sensitive and specific blood markers for the diagnosis of genetic and sporadic CJD and might represent promising tools to predict disease onset

Diagnosis of Creutzfeldt-Jakob disease by measurement of S100 protein in serum: prospective case-control study

Objective: To analyse serum concentrations of brain specific S100 protein in patients with Creutzfeldt-Jakob disease and in controls. Design: Prospective case-control study. Setting: National Creutzfeldt-Jakob disease surveillance unit. Subjects: 224 patients referred to the surveillance unit with suspected Creutzfeldt-Jakob disease and 35 control patients without dementia. Main outcome measure: Serum concentration of S100 protein in patients with Creutzfeldt-Jakob disease, in patients with other diseases causing dementia, and in the control group. Results: Of the 224 patients with suspected Creutzfeldt-Jakob disease, 65 were classed as definitely having the disease after neuropathological verification, an additional 6 were classed as definitely having the disease as a result of a genetic mutation, 43 as probably having the disease, 36 as possibly having the disease, and 74 patients were classed as having other disease. In the 108 patients classed as definitely or probably having Creutzfeldt-Jakob disease the median serum concentration of S100 was 395 pg/ml (SD 387 pg/ml). This was significantly higher than concentrations found in the 74 patients classed as having other diseases (median 109 pg/ml; SD 177 pg/ml; P=0.0001). At a cut off point of 213 pg/ml sensitivity for the diagnosis of the disease was 77.8% (95% confidence interval 68.8% to 85.2%) and specificity was 81.1% (70.3% to 89.3%). There was a significant difference in survival at different concentrations of S100 in Kaplan-Meier curves (P=0.023). Conclusion: Measurement of serum concentrations of S100 is a valuable tool which can be used more easily than tests on cerebrospinal fluid in the differential diagnosis of Creutzfeldt-Jakob disease. More studies are needed to determine whether serial testing of serum S100 improves diagnostic accuracy

Abstracts of the 6th FECS Conference 1998 Lectures

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