Effect of genetic risk factors and disease progression on the cerebrospinal fluid tau levels in Alzheimer's disease

OBJECTIVE: This study was undertaken to gain insights into the clinical utility of measuring cerebrospinal fluid tau protein (CSF-tau) to aid in the diagnosis of Alzheimer's disease (AD). SETTING: AD patients from Tohoku University Hospital, Sendai Japan were sampled. SUBJECTS AND METHODS: CSF-tau levels were examined by sandwich enzyme-linked immunosorbent assay in a total of 62 patients carrying different alpha(1)-antichymotrypsin (ACT) and presenilin-1 (PS-1) polymorphic alleles. Further, the CSF-tau levels were followed up on two occasions during the progression of the disease in 17 AD patients. RESULTS: There was no evident gradient for tau protein in CSF. Neither the ACT/A allele nor the PS-1/1 allele affected the CSF-tau levels. Although CSF-tau levels changed to a variable extent over time, the CSF-tau levels were significantly increased (P < .01) during the follow-up period. Three of the AD patients demonstrated decreasing values, whereas 14 patients showed increasing values. Finally, these temporal changes in CSF-tau levels were not influenced by the apolipoprotein E epsilon 4, ACT/A or PS-1/1 alleles during the progression of AD. CONCLUSION: Regardless of the mechanisms leading to the degeneration of neurons in AD, our findings provide further evidences that monitoring CSF-tau levels may provide useful information about AD irrespective of the background of genetic risks and disease progression.