BioMed Central, Journal of Neuroinflammation, 1(6), p. 22
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Abstract Background Chronic inflammation is a characteristic of Alzheimer's disease (AD). An interaction associated with the risk of AD has been reported between polymorphisms in the regulatory regions of the genes for the pro-inflammatory cytokine, interleukin-6 (IL-6, gene: IL6 ), and the anti-inflammatory cytokine, interleukin-10 (IL-10, gene: IL10 ). Methods We examined this interaction in the Epistasis Project, a collaboration of 7 AD research groups, contributing DNA samples from 1,757 cases of AD and 6,295 controls. Results We replicated the interaction. For IL6 rs2069837 AA × IL10 rs1800871 CC, the synergy factor ( SF ) was 1.63 (95% confidence interval: 1.10–2.41, p = 0.01), controlling for centre, age, gender and apolipoprotein E ε4 ( APOE ε4) genotype. Our results are consistent between North Europe ( SF = 1.7, p = 0.03) and North Spain ( SF = 2.0, p = 0.09). Further replication may require a meta-analysis. However, association due to linkage disequilibrium with other polymorphisms in the regulatory regions of these genes cannot be excluded. Conclusion We suggest that dysregulation of both IL-6 and IL-10 in some elderly people, due in part to genetic variations in the two genes, contributes to the development of AD. Thus, inflammation facilitates the onset of sporadic AD.