For example, the pioneer results shown by Ishida et al., (2012), where methylation patterns of the IL6 promoter gene was differentially hypomethylated in an individual with periodontitis and rheumatoid arthritis, could indicate that the hypomethylated state of a single CpG in the IL6 promoter region may promote higher serum levels of IL6, supporting an important role for this cytokine in the pathogenesis of chronic inflammatory diseases such as rheumatoid arthritis and periodontitis [29]. Here, IL6 is linked to periodontitis.