Elevation of β-amyloid 1-42 autoantibodies in the blood of amnestic patients with mild cognitive impairment

Abstract

Objective: To develop a blood-based test for screening populations at risk for Alzheimer disease. Design: Case-control study. Subjects: A total of 180 patients with mild cognitive impairment (MCI) and 105 age-matched, cognitively normal controls. Interventions: The titer of β-amyloid 1-42 autoantibodies in the plasma was obtained at the time of diagnosis and evaluated by enzyme-linked immunosorbent assay before and after dissociation of the antigenantibody complexes.Atotal of 107 patients with MCI were followed up for 36 months; 70 of the 107 cases progressed to Alzheimer disease. Results: The average level of β-amyloid 1-42 plasma autoantibodies in patients with MCI that progressed to Alzheimer disease, but not that of the stable cases, was significantly higher than in cognitively normal controls (P