Research from the Buck Institute reveals that immune cells derived from the gut, particularly CXCR4+ IgA-producing B cells, migrate into the brain in Alzheimer's disease (AD) mouse models. This trafficking, correlated with increased CXCL12 expression by brain glial cells, suggests a chemokine-mediated gut-brain immune axis implicated in AD pathology. A high-fiber diet was shown to modulate these immune alterations and alleviate disease-related frailty. These findings highlight potential immunological pathways and dietary interventions that could influence neurodegenerative disease progression.