Dissociation between CSF total tau and tau protein phosphorylated at threonine 231 in Creutzfeldt-Jakob disease

To study the potential diagnostic value of abnormally phosphorylated tau protein in Creutzfeldt-Jakob disease (CJD) compared to Alzheimer's disease (AD), we determined levels of tau phosphorylated at threonine 231 (p-tau(231)) and of total tau (t-tau) in cerebrospinal fluid (CSF) of CJD patients, AD patients, and healthy controls (HQ. CID patients showed excessively high t-tau levels but relatively low p-tau(231) concentrations compared to the AD group. t-tau alone yielded the best diagnostic accuracy to differentiate between CID and AD patients, when compared to p-tau(231) and the p-tau(231)/t-tau ratio (97, 78, and 95% correctly allocated cases, respectively). Our findings indicate a dissociation in the direction of change in CSF levels of t-tau and p-tau(231) in CID when compared to AD. (C) 2005 Elsevier Inc. All rights reserved.