Three-year follow-up of cerebrospinal fluid tau, beta-amyloid 42 and 40 concentrations in Alzheimer's disease

Earlier studies have shown elevated levels of tau protein and decreased lev els of amyloid beta 42 in cerebrospinal fluid (CSF) from patients with Alzh eimer's disease (AD). We investigated the concentrations of A beta 42, A be ta 40 and tau in CSF from AD patients on the baseline and after follow-up p eriod of 3 years using ELISA assays. There was a significant decrease of A beta 42 (P < 0.05) and A beta 40 (P < 0.05) levels with time. AD patients w ith the duration of the disease 2 years or less at baseline had more pronou nced decrease of A beta 42 concentrations compared to those with the durati on of the disease more than 2 years at baseline (P < 0.05). CSF tau protein concentrations increased in 9/17 but decreased in 8/17 patients. These res ults suggest that A beta 42 and A beta 40 may be useful in monitoring the l ong-term progression of AD particularly in the early stages of the disease. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.