IL6 and periodontitis: Promoter methylation is an essential epigenetic mechanism for the regulation of theIL-6 expression.16,17 It has been reported that hypomethylation of IL-6promoter was associated with the pathogenesis of systemic lupus erythematosus,rheumatoid arthritis and chronic periodontitis.18,24,29 In the present study, we demonstrated for thefirst time that DNA hypomethylation in IL-6 promoter was associated with increasedrisk for CHD, especially for AMI.