Cerebrospinal Fluid Tau, p-Tau 181 and Amyloid-β38/40/42 in Frontotemporal Dementias and Primary Progressive Aphasias

Background/Aims: We determined cerebrospinal fluid (CSF) concentrations of amyloid-β (Aβ)1–38, Aβ1–40, Aβ1–42, total tau and phospho-tau (p-tau) in order to study their differential expression in frontotemporal dementia (FTD, n = 25) and primary progressive aphasia (PPA, n = 12) as compared to Alzheimer’s dementia (AD, n = 25) and nondemented controls (n = 20). Methods: Commercially available ELISA and electrochemiluminescence methods were applied. Results: High CSF p-tau and low ratios of Aβ1–42/Aβ1–40 and Aβ1–42/Aβ1–38, respectively, were specific for AD. CSF Aβ1–38 was reduced in FTD as compared to each of the other diagnostic groups, including PPA. CSF tau and p-tau levels were elevated in PPA as compared to FTD. Conclusion: This is the first detailed report on biomarker patterns in PPA, indicating distinct CSF biomarker patterns in FTD and PPA as major subgroups of frontotemporal lobar degeneration. The diagnostic and pathophysiological implications of our results warrant further studies on larger and neuropathologically diagnosed patient populations.