Patients with mild cognitive impairment and a reduced CSF Aβ1-42 protein progress rapidly to Alzheimer's disease

Abstract Introduction Some studies have shown that CSF amyloid-beta 1-42 (Aβ 1-42 ), total tau (T-tau) and tau phosphorylated at threonine 181 (P-tau 181p ) proteins are useful diagnostic markers for distinguishing between clinically stable mild cognitive impairment (MCI) patients and those who will develop Alzheimer's disease (AD). Our objective was to test the ability of this technique to discriminate in our cohort of MCI patients, according to the clinical outcome, one year after the lumbar puncture. Material and methods A total of 36 MCI patients were included from the local hospital memory clinic. Using INNO-BIA Alzbio-3 reagents from Innogenetics, we measured CSF Aβ 1-42 , T-tau and P-tau 181p proteins, and calculated the T-tau/Aβ 1-42 and P-tau 181p /Aβ 1-42 ratios. This project was approved by the local ethics committee. Results One year after the lumbar puncture, 14 MCI patients (38%) developed AD. These patients had lower Aβ 1-42 protein levels (285.3 ng/ml vs 377 ng/ml, P 181p /Aβ 1-42 ratio (0.25 vs 0.16, P Conclusions Our MCI patients with lower Aβ 1-42 protein levels and an increased P-tau 181p /Aβ 1-42 ratio progressed quickly to AD. These results may help to identify those MCI patients with a poorer prognosis.