In animal models of Alzheimer’s disease, selective ablation of microglia, the primary source of proinflammatory cytokines in the CNS, or inhibition of TNF signalling, significantly reduces Aβ deposition while rescuing cognitive defects (He et al., 2007; Shi et al., 2011; Sosna et al., 2018). Here, TNF is linked to early-onset autosomal dominant Alzheimer disease.