hTau total ELISA

IBL complements its
dementia marker range

Along with amyloid-β plaques, the formation of tau fibrils within the nerve cells, particularly in the cerebral cortex and notably in the limbic lobe, is another pathological hallmark of Alzheimer's disease. The concentration of Tau in the CSF is a marker of neuronal cell death. In Alzheimer's disease, however, it increases only at a later stage of the disease when the patient already displays significant cognitive impairment. Therefore, the determination of total tau in CSF is important for the diagnosis of Alzheimer's disease in addition to the determination of amyloid β-peptides. However, increased tau levels are found in other neurodegenerative diseases as well. These disorders are generally referred to as tauopathies and include, inter alia, frontotemporal lobar degeneration (FTLD), Pick's disease and corticobasal degeneration (CBD). Tau levels are markedly elevated in Creutzfeldt-Jakob disease.

The hTAU total ELISA from Analytik Jena, manfuactured by AJ Roboscreen and distributed by IBL International, was optimized so that it can be processed in parallel with the IBL Amyloid-β CSF ELISA.

As the graph below shows, the hTAU total ELISA from Analytik Jena, manufactured by AJ Roboscreen and distributed by IBL International, correlates superbly with the INNOTEST ^® hTAU.

Clinical validation of the TAU total ELISA was performed at the University Hospital Erlangen in the CSF Lab of the Department of Psychiatry and Psychotherapy (Prof. Dr. Lewczuk). Tau levels in the cerebrospinal fluid of patients with Alzheimer's disease and mild cognitive impairment (collectively AD (n = 72) and control subjects (n = 41)) show highly significant differences between the groups.

Naturally, the TAU total ELISA, just like our Amyloid-β CSF ELISAs, displays an excellent analytical precision with an inter-assay variance of <5% (Table 1), intra-assay variance of <5% (Table 2) and inter- LOT and operator variance of <6% (Table 3).

Additional advantages of our ELISA are:

• Day assay (4 hours)
• Same protocol as Amyloid-β CSF ELISAs
• Kit controls
• It lends itself to automation

General Information

In 2010, the number of dementia patients worldwide was estimated at 36 million. Assuming an ongoing lack of sufficient preventive and curative treatments, this is expected to double every 20 years. Alzheimer’s Disease accounts for roughly 60‐70% of all dementia cases. Both prevalence and incidence increase with age. Prevalence is around 1% in those aged 65‐69, and more than 30% in those aged 90 or older. The first case of Alzheimer’s Disease was defined and reported in 1907 by German scientist Dr. Alois Alzheimer. He described two hallmarks of the Disease ‐ the plaques and tangles in the brains of Alzheimer’s patients. The plaques are formed by Amyloid-beta peptide deposits and the tangles are composed of hyperphosphorylated Tau proteins. Amyloidosis occurs as early as the preclinical stage. The first cognitive deficits can manifest themselves in the mild cognitive impairment (MCI) stage, while in the dementia stage patients are unable to do any work or daily chores. The concentration of TAU in CSF is therefore recognized as a one biomarker in diagnosing Alzheimer’s Disease. Moreover, a number of independent studies showed that combining TAU‐protein and amyloid‐beta (1‐42) levels will enhance specificity and sensitivity of diagnosis of Alzheimer’s Disease, which is further enhanced when combining TAU levels to Amyloid-beta ratio measurement.