Patients with Alzheimer's disease display a pro-inflammatory phenotype

Background: Inflammation plays a pivotal role in amyloid plaque progression thereby contributing to Alzheimer's disease-related neurodegeneration. We hypothesized that patients with Alzheimer's disease have an innate pro-inflammatory phenotype, as compared to control subjects without dementia. Methods: Patients with a diagnosis of probable Alzheimer's disease (n = 12) and control subjects without signs of dementia (n = 18) were enrolled. Whole blood samples were stimulated ex vivo with endotoxin under standard conditions. Cytokine levels were assessed by ELISA and compared by Mann-Whitneyll-test after log transformation. Results: Patients with Alzheimer's disease had seven- to ten-fold higher IL-I beta production relative to the amount of IL-10 both at the low (p = 0.006) and high concentration of endotoxin (p = 0.007). Subjects who display a pro-inflammatory phenotype as defined by a high IL-1 beta /IL-10 ratio had 13.0-fold higher odds (95% CI: 2.1-82) to have dementia, Conclusion: The data support the hypothesis that a pro-inflammatory phenotype contributes to the development of Alzheimer's disease. (C) 2001 Elsevier Science Inc. All rights reserved.