[Cerebrospinal fluid levels of beta-amyloid protein 1-42 in Alzhemier disease].

OBJECTIVE: To study the role of beta-amyloid protein 1-42 (A beta 1-42) content in the cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients. METHODS: A beta 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 A beta 1-42 mean value for AD was (109.91 +/- 58.78) fmol.L-1. In ND, the A beta 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 A beta 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 A beta 1-42 level was positively correlated with the severity of AD symptoms, but not with the duration. A beta 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 beta-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.