THE ROLE OF MACROPHAGES IN DEGENERATION AND IMMUNE-MEDIATED DEMYELINATION OF THE PERIPHERAL NERVOUS-SYSTEM

Availability of immunoreagents to identify macrophages in tissue and immunopharmacological modification of macrophage responses allow a more comprehensive evaluation of the settings in which macrophages enter the nervous system and permit a better understanding of the role they play in the pathogenesis of peripheral nerve disease. Selected aspects of macrophage behavior in Wallerian degeneration and immune-mediated demyelination are summarised. After nerve transection macrophages selectively infiltrate degenerating nerve fibres, degrade and phagocytose myelin debris plus concomitantly release humoral factors such as apolipoprotein E and interleukin 1 which are involved in nerve regeneration and remyelination. Early in acute T-cell mediated demyelinating polyneuropathies macrophages serve as antigen-presenting cells. In the effector phase macrophages adhere to intact nerve fibres, release toxic substances, and actively strip off myelin sheaths which results in demyelination. In chronic relapsing polyneuropathies macrophages participate in the destruction of myelin sheaths presumably in conjunction with antibodies to myelin components. © 1992 Pergamon Press Ltd.