CSF Abeta42, Tau and phosphorylated Tau, APOE epsilon4 allele and MCI type in progressive MCI.

BACKGROUND The patients with mild cognitive impairment (MCI) have an elevated risk for Alzheimer's disease (AD). Especially the amnestic MCI is seen as prodrome of AD. Apolipoprotein E (APOE) epsilon4 allele, abnormal CSF Abeta42, Tau and phosphorylated Tau (phospho-Tau) levels are associated with elevated risk for AD. METHODS APOE genotyping was done by PCR based method and baseline CSF Abeta42, Tau and phospho-Tau were measured by ELISA from 60 controls and 79 MCI patients. RESULTS Thirty-three MCI patients developed dementia during an average of 3.5 years follow-up. CSF Abeta42 was decreased and Tau and phospho-Tau were increased in the progressive MCI patients. The APOE epsilon4 allele was more frequent in the progressive MCI patients. The APOE epsilon4 allele showed a dose dependent association o the Abeta42 levels in the progressive MCI patients and to all of the markers in controls. CONCLUSIONS Decreased CSF Abeta42 and elevated Tau or phospho-Tau together with APOE epsilon4 allele are highly predictive for the dementia in MCI patients with amnestic or executive symptoms.