The role of the immune system in Alzheimer disease: Etiology and treatment.

The immune system is now considered a major factor in Alzheimer Disease (AD). This review seeks to demonstrate how various aspects of the immune system, both in the brain and peripherally, interact to contribute to AD. We highlight classical nervous system immune components, such as complement and microglia, as well as novel aspects of the peripheral immune system that can influence disease, such as monocytes and lymphocytes. By detailing the roles of various immune cells in AD, we summarize an emerging perspective for disease etiology and future therapeutic targets.