Serum Interleukin-10 Levels Correlate with Cerebrospinal Fluid Amyloid Beta Deposition in Alzheimer Disease Patients

<b><i>Background and Objective:</i></b> In Alzheimer disease (AD) inflammation becomes evident throughout the course of the disease. However, the association between inflammation, cognitive impairment, and cerebrospinal biomarkers (Aβ42, t-tau, p-tau181, and Aβ42/p-tau181 ratio) is poorly understood. <b><i>Methods:</i></b> A large panel of inflammatory cytokines (interleukin [IL]-1β, IL-1ra, IL-2, IL-4, IL-6, IL-10, IL-17, interferon-&#x03B3;, tumor necrosis factor-α, and vascular endothelial growth factor) was analyzed using a multiplex immunoassay in 27 patients with a diagnosis of AD dementia and in 18 control subjects. In a subgroup with available cerebrospinal fluid (CSF) samples, cytokines in serum were correlated with the levels of neurodegenerative CSF biomarkers (Aβ42, t-tau, p-tau181, and Aβ42/p-tau181 ratio). <b><i>Results:</i></b> Compared to control subjects, AD patients showed a significant upregulation of IL-10, IL-1β, and IL-17 serum levels. Several cytokines appeared intercorrelated, and IL-10 in particular presented a significant inverse correlation with CFS levels of Aβ42 and the Aβ42/p-tau ratio. <b><i>Conclusion:</i></b> Our findings indicate that serum levels of IL-10 may represent a possible peripheral expression of amyloid beta deposition in AD patients.