Cerebrospinal Fluid Profile of Tau, Phosphorylated Tau, Aβ42, and Aβ40 in Probable Cerebral Amyloid Angiopathy.

Abstract

There is no consensus regarding the diagnostic value of cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers in cerebral amyloid angiopathy (CAA). To describe the CSF levels of Aβ42, Aβ40, total protein Tau, and phosphorylated-Tau (p-Tau) in a large series of probable CAA patients and to compare with AD patients in order to identify a specific pattern in CAA but also to look for correlations with the neuroimaging profile. We retrospectively included from 2 French centers probable CAA patients according to modified Boston criteria who underwent lumbar puncture (LP) with CSF AD biomarker quantifications. Two neurologists independently analyzed all MRI sequences. A logistic regression and Spearman's correlation coefficient were used to identify correlation between MRI and CSF biomarkers in CAA. We included 63 probable CAA and 27 AD patients. Among CAA 50.8% presented with decreased Aβ42 level associated with elevated p-Tau and/or Tau, 34.9% with isolated decreased Aβ42 level and 14.3% patients with normal Aβ42 level. Compared to AD, CAA showed lower levels of Tau (p = 0.008), p-Tau (p = 0.004), and Aβ40 (p = 0.001) but similar Aβ42 level (p = 0.07). No correlation between Aβ42 or Aβ40 levels and neuroimaging was found. CSF biomarkers may improve the accuracy of the modified Boston criteria with altered profile in 85% of the patients fulfilling revised Boston criteria for probable CAA. Aβ40 appears as an interesting selective biomarker in differential diagnosis.