TNFRSF1A and brain ischemia: Genome-wide association studies have identified a polymorphism in the TNF gene, which enhances stroke susceptibility, suggesting a pivotal role of TNF/TNFR1 in the etiopathogenesis of stroke.232 Moreover, TNF levels are significantly upregulated upon cerebral ischemia, whereby they mediate neuronal plasticity.233 As previously mentioned, TNF is secreted mainly by microglia, which protect against cerebral ischemia.