[Diagnostic value of tau in cerebrospinal fluid in alzheimer disease]

To search for reliable and quantitative biochemical marker for diagnosis of Alzheimer disease.

ELISA-double enzyme amplification assay was used to detect the total tau and abnormally hyperphosphorylated (p-tau) in cerebrospinal fluid specimens of patients with Alzheimer disease (AD, N = 52, 30 from the Netherlands and 22 from Wuhan and Haikou, China), vascular dementia (VD, N = 46, 18 from the Netherlands and 28 from Haikou), and non-neurological disease (N = 37, 13 from the Netherlands and 24 from Haikou) and of normal elderly controls (N = 56, 26 from the Netherlands, and 30 from Wuan and Haikou).

The measurement of CSF specimens from Netherlands Brain Bank showed that the levels of total tau and p-tau in CSF specimens of AD patients were significantly higher than those in CSF of patients with VD and non-dementia neurological disorders, and of age-matched non-neurological normal controls. With CSF tau > or = 370 pg/ml as the marker for diagnosis of AD, the sensitivity, specificity, reliability as well as differentiation rate of AD from VD were 90.0%, 79.0%, 82.8% and 66.7%, respectively. With CSF p-tau > or = 120 pg/ml as the marker for diagnosis of AD, the sensitivity, specificity, reliability as well as differentiation rate of AD from VD were 93.3%, 89.5%, 90.8%, and 83.3% respectively. The measurement of total and phosphorylated taus in CSF specimens of AD and non-AD patients and normal controls collected in China showed the similar results; and the sensitivity, specificity, reliability as well as differentiation rate of AD from VD were 77.3%, 85.4%, 83.7% and 71.4% with CSF tau > or = 120 pg/ml as the marker for diagnosis of AD. There was no correlation between CSF tau and p-tau and age, sex, and seriousness of disease.

Increased phosphorylated tau in human cerebrospinal fluid is a reliable biomarker for diagnosis of Alzheimer disease.