Myelin-induced experimental allergic encephalomyelitis in Lewis rats: Tumor necrosis factor alpha levels in serum and cerebrospinal fluid - Immunohistochemical expression in glial cells and macrophages of optic nerve and spinal cord

Tumor necrosis factor alpha (TNF alpha) activity was measured in serum and cerebrospinal fluid (CSF) of Lewis rats after experimental allergic encephalomyelitis (EAE) induction and during the clinical course of acute disease. TNF alpha bioactivity expression preceded the clinical symptoms and paralleled the severity of disease. We further investigated the identity of the central nervous system (CNS) cells involved in TNF alpha expression and their regional localization during EAE. Tissue sections of brain, cerebellum, dorsal spinal cord and optic nerve were studied by indirect double labelling immunofluorescence. Spinal cord white matter and optic nerve showed a widespread TNF alpha immunoreactivity at critical stages of EAE in macrophages/microglia and astrocytes. We have shown changes in CSF/serum albumin ratio and immunoglobulin G index during EAE. Our results confirm the very important role of TNF alpha in EAE.