Anion exchange proteins are a component of corpora amylacea in Alzheimer disease brain

Corpora amylacea (CAm) are amorphous structures that increase in number in the brains of patients with neurodegenerative diseases. We found abundant CAm in the brains of Alzheimer disease (AD) patients. We show here that proteins of the anion exchanger (AE) gene family, related to erythrocyte band 3, are present in CAm. The presence of AE epitopes in CAm may be related to the presence of AE proteins in membranes of neurones, and their altered expression level in degenerating neurones in AD brains. Whereas the distribution of immunoreactivity was uniform over the CAm in control brains, there was much more variation in staining of CAm core and peripheral structures in AD brains. Our data support the suggestion that accumulation of altered neuronal membrane proteins may be involved in the pathogenesis of CAm in AD.