Alzheimer's Disease and the Immune System

Abstract

Alzheimer's disease (AD) has been known for over 100 years, but has only just become a pressing matter at the end of the 21st century. AD is a disease related to the aging of the individual, and has its burden over the population has continued to increase as medicine and technology are continuing to lengthen the lives of individuals. Changes in the body associated with aging, such as a weaker immune system, are causing the buildup of the protein associated with AD, amyloid beta (Aβ). Although the monomer forms of this peptide are a normal occurrence within the body, the oligomer or higher multi- unit forms of the peptide present problems to the neurons and local environment in the CNS. The molecules become toxic to the area, and they are flagged by the body to be cleared. Antibody production, opsonization, and phagocytosis by astrocytes and microglia cells in the brain have been shown to help clear this burden. However, this clearing process also can trigger pro-inflammatory pathways and secrete inflammatory cytokines, and this inflammatory response goes on to further promote the pathological changes associated with AD. One of the major progressors of AD is the dysfunction of the immune system caused by abnormal peptide folding in the CNS. Although the immune system of aged patients tend to be fragile with respect to function, acting through immune modulation and immunotherapy are currently seen to be some of the most beneficial techniques for age related diseases. In this review, we will discuss the relation of AD to age and the immune system, and then introduce the current options and treatments regarding immune modulation and immunotherapy.