Levels of plasma brain‐derived tau and p‐tau181 in Alzheimer's disease and rapidly progressive dementias

Abstract

AbstractINTRODUCTIONRapidly progressive dementias (RPDs) are a group of neurological disorders characterized by a rapid cognitive decline. The diagnostic value of blood‐based biomarkers for Alzheimer's disease (AD) in RPD has not been fully explored.METHODSWe measured plasma brain‐derived tau (BD‐tau) and p‐tau181 in 11 controls, 15 AD patients, and 33 with RPD, of which 19 were Creutzfeldt‐Jakob disease (CJD).RESULTSPlasma BD‐tau differentiated AD from RPD and controls (p = 0.002 and p = 0.03, respectively), while plasma and cerebrospinal fluid (CSF) p‐tau181 distinguished AD from RPD (p < 0.001) but not controls from RPD (p > 0.05). The correlation of CSF t‐tau with plasma BD‐tau was stronger (r = 0.78, p < 0.001) than the correlation of CSF and plasma p‐tau181 (r = 0.26, p = 0.04). The ratio BD‐tau/p‐tau181 performed equivalently to the CSF t‐tau/p‐tau181 ratio, differentiating AD from CJD (p < 0.0001).DISCUSSIONPlasma BD‐tau and p‐tau181 mimic their corresponding cerebrospinal fluid (CSF) markers. P‐tau significantly increased in AD but not in RPD. Plasma BD‐tau, like CSF t‐tau, increases according to neurodegeneration intensity.