Gingival Crevicular Fluid Levels of Cathelicidin LL-37 and Interleukin-18 in Patients With Chronic Periodontitis

Background: Cathelicidin LL-37, an antimicrobial peptide, is part of the host innate immune response in the oral cavity. Interleukin (IL)-18, a proinflammatory cytokine, could play a role in the progression of the inflammatory response. The aim of the present study was to determine the levels of cathelicidin LL-37 and IL-18 in the gingival crevicular fluid (GCF) of patients with gingivitis and chronic periodontitis. Methods: Fifty-nine subjects were included in the present study. Probing depth (PD), clinical attachment level (CAL), plaque index (PI), bleeding on probing, and papilla bleeding index (PBI) were assessed in patients with chronic periodontitis or gingivitis and in healthy controls. GCF levels of cathelicidin LL-37 and IL-18 were analyzed by enzyme-linked immunosorbent assay. Results: GCF levels of cathelicidin LL-37 were significantly elevated in patients with chronic periodontitis compared to the other groups (P<0.05). No significant difference was found in the total amount of GCF IL-18 among the study groups (P>0.05). Spearman correlation analysis revealed a positive relationship between levels of GCF cathelicidin LL-37 and PD, CAL, PI, and PBI at the sampled sites (P<0.01), whereas no correlation was found between the total amount of GCF IL-18 and clinical periodontal parameters at the sampled sites (P>0.05). Conclusion: Elevated levels of GCF cathelicidin LL-37 in chronic periodontitis suggest that it may play a role in the host innate immune response during periodontal inflammation. J Periodontol 2009;80:969-976.