Epigenetic characteristics in inflammatory candidate genes in aggressive periodontitis.

BACKGROUND: Periodontitis is a chronic inflammatory disease triggered by the host immune response. Epigenetic modifications also affect the immune response. We assessed CpG methylation in 22 inflammatory candidate genes (ATF2, CCL25, CXCL14, CXCL3, CXCL5, CXCL6, FADD, GATA3, IL10RA, IL12A, IL12B, IL13, IL13RA1, IL15, IL17C, IL17RA, IL4R, IL6R, IL6ST, IL7, INHA, and TYK2) with respect to the occurrence of aggressive periodontitis (AgP).

PATIENTS AND METHODS: In this study 15 AgP patients (53.3% males, 41.4±10.5 years) and 10 controls (40.0% males, 36.9±17.5 years) were included. The methylation patterns of gingival biopsies were quantified using EpiTect® Methyl Signature PCR Array Human Inflammatory Response.

RESULTS: In gingival biopsies taken from patients with AgP, CpG methylation of CCL25 (1.73% vs. 2.59%, p=0.015) and IL17C (6.89% vs. 19.27%, p=0.002) was significantly reduced as compared with periodontally healthy tissues.

DISCUSSION: We showed for the first time a differential methylation pattern for CCL25 and IL17C in periodontitis. CCL25 plays an important role in T-cell development, whereas IL17C regulates innate epithelial immune responses. The decrease in CpG methylation is presumably accompanied by an increase in gene expression. This could lead to a greater availability of CCL25 and interleukin 17C and support periodontal loss of attachment.