Objectives: To examine the localization and amount of IC in human gingival tissues.
Methods: Gingival tissues were obtained from 6 aggressive periodontitis (AP), 5 chronic periodontitis (CP) patients, and 8 periodontally healthy control subjects (CS). Biotin-conjugated C1q was used to identify the deposition of IC containing IgG-antibody (IC-IG) in tissue sections. Total IC-IgG was measured in gingival tissue homogenates using immobilized C1q as an IC detection module in an ELISA system. Cytokines in the homogenates were also monitored by ELISA. Kruskal-Wallis statistical analysis was used to compare the groups.
Results: Deposition of IC-IG was found in the gingival epithelium and connective tissue of CP, but little or no IC-IG in healthy control tissue. The concentrations of IC-IgG levels were higher in gingival tissue homogenates of AP and CP than CS. IC containing IgG2 antibody were higher in AP and CP than in CS. In addition, ICs containing IgG3 and IgG4 exhibited higher levels in CP than in CS. The amount of pro-inflammatory cytokine IL-1ß was higher in tissues of AP and CS than CS. However, anti-inflammatory TSLP levels were higher in CS than in periodontally diseased tissue (p=0.0523), while IL-10 did not differ according to the periodontal condition. Collectively, the level of IC-IgG in the gingival tissue appeared to be associated with the level of periodontal inflammation.
Conclusion: Local deposition and elevated level of IC were found in human gingival tissues with periodontitis compared to periodontally healthy gingiva, suggesting that IC may exacerbate pro-inflammatory immune responses.
Support by DE03420, DE18310, DE18499 (NIH/NIDCR), FAPESP 2007/53888-8, CNPq 201348/2007-1.