IL-6 detection in multiple sclerosis brain

By using a double‐label immunohistochemistry technique, we demonstrated the presence of interleukin‐6 (IL‐6) in acute and chronic active plaques from the brain of six patients with multiple sclerosis (MS). IL‐6 was mainly associated with astrocytes and rarely with macrophages or mononuclear infiltrating cells. The pattern of distribution for IL‐6 immunoreactivity was similar to that of HLA‐DR expression, but the two molecules almost never colocalized on the same cell. Our data indicate that in MS central nervous system IL‐6 is predominantly located within resident glial cells which are concentrated at the sites of ongoing demyelination and immune activation. Although IL‐6 exhibits several proinflammatory activities, indirect evidence suggests that the cytokine may also play an immunomodulatory role in inflammatory demyelinating disorders.