CSF interferon-β: A key player in Alzheimer’s disease pathogenesis and cognitive impairment

Abstract Recent research has postulated that the activation of interferon signaling pathways could be implicated in the pathogenesis of Alzheimer's disease (AD). However, the precise types of interferons and related cytokines, both from the brain and periphery, responsible for cognitive impairment in patients with AD remain unclear. A total of 131 participants (78 [59.5%] female and 53 [40.5%] male; mean [SD] age, 61.5 [7.6] years) with normal cognition and cognitive impairment from the China Aging and Neurodegenerative Initiative cohort were included. CSF and serum IFNα-2a, IFN-β, IFN-γ, TNF-α, IL-6, IL-10, MCP-1and CXCL-10 were tested. The correlation between these interferons and related cytokines with AD core biomarkers in the CSF and plasma, cognition performance, and brain MRI measures were analyzed. We found that only CSF IFN-β levels were significantly elevated in Alzheimer’s disease compared to normal cognition. Furthermore, CSF IFN-β levels were significantly associated with AD core biomarkers (CSF P-tau and Aβ42/Aβ40 ratio) and cognitive performance (MMSE and CDR score). Additionally, the CSF IFN-β levels were significantly correlated with the typical pattern of brain atrophy in AD (such as hippocampus, amygdala, and precuneus). In contrast, CSF IL-6 levels were significantly elevated in non-AD cognitively impaired patients compared to other groups. Moreover, CSF IL-6 levels were significantly associated with cognitive performance in non-AD individuals and correlated with the vascular cognitive impairment-related MRI markers (such as white matter hyperintensity). Our findings demonstrate that distinct inflammatory molecules are associated with different cognitive disorders. Most notably, CSF IFN-β levels are significantly linked to the pathology and cognitive performance of AD, identifying this interferon as a potential target for AD therapy.