Fig. 2
From: Peripheral and central neuroimmune mechanisms in Alzheimer’s disease pathogenesis
Impact of peripheral immunity on the CNS in AD brain. In AD, peripheral immune cells infiltrate the dura mater, subarachnoid space, and brain parenchyma, disrupting CNS immune homeostasis through clonal expansion, abnormal antigen accumulation, and excessive inflammatory mediator release. Within the brain parenchyma, microglia and astrocytes transition from homeostatic to reactive states, amplifying inflammation and accelerating neurodegeneration. This cascade of events progressively compromises neuronal integrity, leading to structural and functional deterioration.