Antibody‐Antigen Dissociation: A Novel Diagnostic Tool in Alzheimer Disease

With the increasing population of aged individuals with Alzheimer disease (AD), the cost of assessment and ineffectiveness of treatment following diagnosis, there is an urgent need for a sensitive, non‐invasive, diagnostic standard. In the search for a biomarker, no consistent change in plasma amyloid‐beta levels has been found in AD patients. In biological fluids, antibodies and antigens are in a state of dynamic equilibrium that is concentration dependent. As such, when complexed, antigen effectually masks a proportion of its corresponding antibody, and limits both antibody and antigen detection. This interaction can be interrupted, thus freeing antibody and antigen and providing a more accurate analysis of antibody titers and antigen concentration. In this study, sera collected from 36 AD patients and 24 age‐matched controls were examined before and after dissociation. Statistical analysis shows no difference between AD and control patients before dissociation. After dissociation, however, the level of amyloid‐beta f nantibody assessed was greater than before dissociation in all cases. Importantly, levels from AD cases are much greater than controls. The importance of measuring total amounts of antigen or antibody following unmasking, has been shown to be very important, and as shown here, could be an important diagnostic tool in AD.