 A deficiency in MAC-2 expression can even cause inhibition of myelin removal from injury sites.Schwann cells are active in demyelination of injured nerves before macrophages are even present at the site of nerve injury.Electron microscopy and immunohistochemical staining analysis of teased nerve fibers shows that before macrophages arrive at the injury site, myelin is fragmented and myelin debris and lipid droplets are found in the cytoplasm of Schwann cells, indicating phagocytic activity before macrophages arrive.