Measurement of phosphorylated tau epitopes in the differential diagnosis of Alzheimer disease: a comparative cerebrospinal fluid study.

• BACKGROUND: Abnormal hyperphosphorylation of the microtubule-associated protein tau and its incorporation into neurofibrillary tangles are major hallmarks of the pathogenesis of Alzheimer disease (AD). Different tau phosphoepitopes can be sensitively detected in cerebrospinal fluid (CSF). OBJECTIVE: To compare the diagnostic accuracy of CSF concentrations of tau proteins phosphorylated at 3 pathophysiologically important epitopes (p-tau) to discriminate among patients with AD, nondemented control subjects, and patients with other dementias. DESIGN AND SETTING: Cross-sectional, bicenter, memory clinic-based studies. PARTICIPANTS: One hundred sixty-one patients with a clinical diagnosis of AD, frontotemporal dementia, dementia with Lewy bodies, or vascular dementia and 45 nondemented controls (N = 206). MAIN OUTCOME MEASURES: Levels of tau protein phosphorylated at threonine 231 (p-tau231), threonine 181 (p-tau181), and serine 199 (p-tau199). The CSF p-tau protein levels were measured using 3 different enzyme-linked immunosorbent assays. RESULTS: The mean CSF levels of the studied p-tau proteins were significantly elevated in patients with AD compared with the other groups. Applied as single markers, p-tau231and p-tau181 reached specificity levels greater than 75% between AD and the combined non-AD group when sensitivity was set at 85% or greater. Statistical differences between the assay performances are presented. Particularly, discrimination between AD and dementia with Lewy bodies was maximized using p-tau181at a sensitivity of 94% and a specificity of 64%, and p-tau231 maximized group separation between AD and frontotemporal dementia with a sensitivity of 88% and a specificity of 92%. Combinations of the 3 markers did not add discriminative power compared with the application as single markers. CONCLUSIONS: The p-tau proteins in CSF come closest to fulfilling the criteria of a biological marker of AD. There is a tendency for p-tau proteins to perform differently in the discrimination of primary dementia disorders from AD.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Psykiatri (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Psychiatry (hsv//eng)

Keyword

Aged

Aged

80 and over

Alzheimer Disease

cerebrospinal fluid

diagnosis

Cross-Sectional Studies

Dementia

cerebrospinal fluid

diagnosis

Dementia

Vascular

cerebrospinal fluid

diagnosis

Diagnosis

Differential

Enzyme-Linked Immunosorbent Assay

Epitopes

cerebrospinal fluid

Female

Humans

Lewy Body Disease

cerebrospinal fluid

diagnosis

Male

Middle Aged

Phosphoric Acid Esters

cerebrospinal fluid

Phosphorylation

Predictive Value of Tests

Reference Values

tau Proteins

cerebrospinal fluid

Publication and Content Type

ref (subject category)

art (subject category)