The mechanism by which this effect occurs includes the induction of pathogenicity-related gene (IL-23R,31,158 TGF-β3158) expression and the suppression of anti-inflammatory IL-10.159 IL-23 was secreted by myeloid APCs exposed to P. gingivalis160,161 and periodontal ligament fibroblasts stimulated by IL-1β.161 The correlation between the amount of IL-23 in the GCF and attachment loss was also determined in chronic periodontitis patients.162. This evidence concerns the gene IL37 and chronic periodontitis.