From infection to dysfunction: viral triggers and antiviral immune factors in Alzheimer's disease pathology.

Neurodegenerative diseases and neurocognitive disorders increasingly appear to share a common and underappreciated contributor: the viral-immune axis in the brain. This review presents current evidence linking neurotropic viruses and host antiviral immunity to the onset and progression of neurodegeneration and neurocognitive dysfunction. We explore how viral infections, particularly by Herpesviruses, Severe Acute Respiratory Syndrome Coronavirus 2, and Human Immunodeficiency Virus, disrupt neural homeostasis through neuroinflammation, amyloidosis, tauopathy, and autophagy dysregulation in neurodegeneration including Alzheimer's disease (AD). Simultaneously, host antiviral mechanisms, including type I interferons and interferon regulatory factors, often amplify neuronal damage when dysregulated. By examining viral and immune interactions within the neurodegenerative diseases, this review aims to broaden our understanding of the viral-immune axis in the brain and inspire novel approaches to prevention and treatment.