Cerebrospinal fluid levels of tau phosphorylated at threonine 181 in patientswith Alzheimer's disease and vascular dementia.

In 31 patients with probable Alzheimer’s disease
(AD), 19 with probable vascular dementia (VaD) and 20
with Possible AD and Possible VaD, cerebrospinal fluid
(CSF) tau levels hyperphosphorylated at threonine 181 (Ptau)
were measured by ELISA. Thirty-six age-matched subjects
were used as controls. The severity of the cognitive
decline was assessed at the time of CSF analysis and after a
12-month follow-up. The groups had comparable age,
degree of cognitive impairment and disease duration; these
parameters were not related to P-tau levels. P-tau discriminated
between demented patients and controls, but no significant
difference emerged between AD and the other
groups. By contrast, higher P-tau values were found to predict,
independently of the clinical diagnosis, a more rapid
evolution of cognitive decline. Whether these findings are
due to a lack of CSF P-tau specificity or to the low reliability
of clinical and radiological criteria remains unclear.
P-tau may be useful in the evaluation of disease evolution,
by predicting the rate of cognitive decline.