title: Longitudinal stability of CSF tau levels in Alzheimer patients.
abstract: BACKGROUND
  Antemortem levels of tau in the cerebrospinal fluid (CSF) of Alzheimer's disease (AD) patients have repeatedly been demonstrated to be elevated when compared to controls. Although CSF tau has been reported to be elevated even in very mild AD, it is unknown how tau levels change during the course of the disease.
  
  
  METHODS
  We have followed 29 mild-to-moderately affected AD subjects over 2 years with repeated CSF taps. Clinical measures of dementia severity (Clinical Dementia Rating Scale, Global Deterioration Scale and Mini-Mental Status Examination) were obtained at the start and conclusion of the observation period, and CSF tau was measured with a standard enzyme-linked immunoabsorbent assay (ELISA) using two monoclonal antibodies.
  
  
  RESULTS
  Despite significant changes in the clinical measures consistent with progression of the disease, no significant overall change in CSF tau levels (548 +/- 355 vs. 557 +/- 275 pg/mL, NS) was observed. None of the clinical variables was significantly correlated with either baseline measures of CSF tau or delta CSF tau (last-first). Similarly, CSF tau at baseline and changes over time were not significantly related to Apolipoprotein E (APO E) phenotype.
  
  
  CONCLUSIONS
  These data suggest that CSF tau levels are stable over extended periods of time in a group of mild-to-moderately demented AD subjects and that CSF tau levels do not predict the severity or rate of progression of AD, at least not during the middle stages of the illness.
authors.affiliation: Geriatric Psychiatry Branch, National Institute of Mental Health, NIH, Bethesda, MD 20892-1275, USA.
authors.forename: T
authors.initials: T
authors.lastname: Sunderland
authors.forename: B
authors.initials: B
authors.lastname: Wolozin
authors.forename: D
authors.initials: D
authors.lastname: Galasko
authors.forename: J
authors.initials: J
authors.lastname: Levy
authors.forename: R
authors.initials: R
authors.lastname: Dukoff
authors.forename: M
authors.initials: M
authors.lastname: Bahro
authors.forename: R
authors.initials: R
authors.lastname: Lasser
authors.forename: R
authors.initials: R
authors.lastname: Motter
authors.forename: T
authors.initials: T
authors.lastname: Lehtimäki
authors.forename: P
authors.initials: P
authors.lastname: Seubert
mesh_terms: D000368:Aged; D000483:Alleles; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid* / Q000175:diagnosis; D000911:Antibodies, Monoclonal; D001057:Apolipoproteins E / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010641:Phenotype; D012016:Reference Values; D012720:Severity of Illness Index; D013997:Time Factors; D016875:tau Proteins / Q000134:cerebrospinal fluid*
chemical_list: D000911:Antibodies, Monoclonal; D001057:Apolipoproteins E; D016875:tau Proteins