The immune system makes antibodies to the brain proteins due to various reasons which occur primarily outside the brain. These antibodies circulate in the blood and are not a threat to the brain as long as the blood-brain barrier is intact. However, if the BBB is compromised, these antibodies can penetrate the brain, react with brain proteins and result in neuroinflammation and neurodegeneration.
Elevated antibody levels against one or more of these amyloidogenic (plaque-forming) proteins puts a person at a higher risk for developing AD.
Tau is a phosphatase protein and its primary job is to facilitate tubulin assembly. Its job is to keep the neurons naturally free of amyloid-beta clumps and other toxic forms of proteins. Due to oxidative stress in patients with cognitive decline, tau becomes phosphorylated, misfolded, or aggregated.
This change in the molecular structure of tau protein makes it a target of the immune system, which can result in the production of anti-tau antibodies.
Low amounts may be detected in elderly individuals without cognitive decline, which may be considered due to the natural aging process and accompanying destruction of neurons.
Cyrex's Alzheimer's LINX tests for Tau and many other early indicators of degenerative disease.