Role of microglia in multiple sclerosis.

Microglia are the resident macrophages of the nervous system. They serve to protect and preserve neuronal cells from pathogens and facilitate recovery from metabolic insults. In addition, they appear to play a role in the neuropathology of noninfectious inflammatory disorders of the central nervous system, especially those that are autoimmune. Presentation of neural autoantigens to autoreactive T cells by microglia and the attendant secretion of proinflammatory cytokines are thought to facilitate the inflammatory process in diseases such as multiple sclerosis. They also serve as scavengers of damaged myelin following death of oligodendrocytes and the destruction of myelin and may, therefore, promote recovery of myelin damaged by the inflammatory insult. This review examines the current controversies on the pathology of multiple sclerosis and the role played by microglia in the development of central nervous system demyelination.