Basic and Clinical Studies on the Measurement of β-amyloid(1–42) in Cerebrospinal Fluid as a Diagnostic Marker for Alzheimer's Disease and Related Disorders: Multi Center Study in Japan

Background: The development of diagnostic markers for earlier and more accurate clinical diagnosis of Alzheimer's disease (AD) is essential to identify unequivocally AD patients during life. This study is to investigate the basic performance and clinical significance of β-amyloid(1–42) (Aβ42) level measurement in cerebrospinal fluid (CSF) alone or in combination with CSF tau for distinguishing AD from non-AD disorders. Methods: The basic characteristics of the reagent for measuring Aβ42, which used Sandwich ELISA, was examined. The clinical studies were done at 5 centers in Japan. CSF samples from 353 patients were collected and classified into the following six groups; AD (n=189), Mild Cognitive Impairment (MCI: n=25), Neurodegenerative disorders without AD (ND: n=66), Cerebrovascular disturbance (CVD: n=28), Other neurological disorders (OND: n=18) and Neurological control (NC: n=27) group. Results: Mean levels of Aβ42 in CSF were significantly lower in AD (395 pg/mL) than MCI (586 pg/mL;p 0.67) of MCI patients who had progressed to AD within a few years was 79% (15/19). Conclusion: The combined measurement of CSF Aβ42 and tau is clinically a useful diagnostic marker to discriminate AD at an early stage including MCI from normal aging and other related disorders.