The decline in mental fitness associated with Alzheimer disease is accompanied by physical
changes in the brain, including the development of characteristic plaques and neurofibrillary
tangles, but the pathogenesis of those changes is not clear. Recent work suggests that the
activation of microglia in response to injury, illness, aging, or other causes begins a cascade
of events that can best be characterized as an inflammatory process. This cascade is
mediated at first by the proinflammatory cytokine interleukin 1, which is overexpressed by …