Brain immune responses cognitive decline and dementia: relationship with phenotype expression and genetic background.

Alzheimer's disease (AD) is a progressive degenerative disease of the brain and the most frequent cause of dementia among elderly. The etiology of AD is still obscure, but genetic and environmental factors appear to play differential roles in the disease. Several evidence suggest that inflammation or altered immune responses may play an important role in this disease. The following topics will be discussed: (1) the association of inflammation with brain degenerative processes in AD; (2) the influence of cytokine gene polymorphism upon the risk of developing AD and/or the age at onset of manifestation clinical dementia; (3) the effects of gene allele variations upon the phenotype of immune molecules in the blood and brain of AD patients; (4) the association of genetic variations in some of this molecules with the progression of the disease and cognitive decline.