Differences between plasma and CSF p-tau181 and p-tau231 in early Alzheimer’s disease

Plasma phosphorylated tau species have been recently proposed as peripheral markers of Alzheimer’s disease pathology. In this cross-sectional study incuding ninety-one subjects, plasma p-tau181 and p-tau231 levels were elevated in the early symptomatic stages of AD, with similar levels than those of CSF. Plasma p-tau231 and p-tau181 were strongly related to CSF tau and amyloid and exhibited a high accuracy – close to CSF p-tau231 and p-tau181 – to identify AD already in the early stage of the disease. The findings might support the use as diagnostic and prognostic peripheral AD biomarkers in both research and clinical settings. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was not funded. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved and waved by the Ethic Comitte of the ASST Spedali Civili of Brescia (NP 1471, DMA Study waved in 26.08.2019, Brescia) and was in conformity with the Helsinki Declaration; informed consent was obtained from all participants. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes the data are available upon reasonable request from the authors