Anti-inflammatory cytokines: Expression and action in the brain

Transforming growth factor-β₁ (TGF-β₁) and interleukin (IL)-10 gene expression is equivocal in normal brain and upregulated in over a dozen central and peripheral diseases/disorders. The patterns of specific expression of cytokines differ in these diseases. Published data indicate that these cytokines are produced by and act on both neurons and glial cells. Although their actions are commonly viewed as 'anti-inflammatory', they protect neurons and downregulate the responses of glial cells to diseases/disorders in the absence of inflammation. Their actions counterbalance the actions of elevated IL-1 and/ or tumor necrosis factor-α to maintain homeostasis. Their therapeutic potential will be realized by improving our understanding of their place in neural cytokine networks.