Cerebrospinal fluid levels of β-amyloid protein 1-42 in Alzhemier disease

Objective To study the role of β amyloid protein 1 42 (Aβ 1-42 ) content in the cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients. Methods Aβ 1-42 levels were measured with the ELISA method in AD (n=30), non AD (NAD, n=25) and non dementia (ND, n=21). Results The Aβ 1-42 mean value for AD was (109.91±58.78 ) fmol·L -1 . In ND, the Aβ 1-42 mean value was (242.40±142.58) fmol·L -1 . The mean value for AD was significantly lower than that of ND. In NAD, the Aβ 1-42 mean value was (231.70±143.94) fmol·L -1 , and it was not significantly different from the mean value for ND. The Aβ 1-42 level was positively correlated with the severity of AD symptoms, but not with the duration. Aβ 1-42 levels in CSF of AD were significantly lower than that of ND, and they decreased as the severity of disease increased. Conclusion Cerebrospinal fluid β amyloid 1 42 analyses may be of value in the clinical diagnosis of Alzheimer's disease, especially in the earlier course of the disease, when drug therapy may have the greatest effect but clinical diagnosis is particularly difficult.