Interleukin-8 and Anti-interleukin-8 Autoantibodies in Gingival Crevicular Fluid from Patients with Periodontitis

Interleukin-8 (IL-8) is believed to play an important role in the pathogenesis of various forms of periodontitis. In addition, the anti-IL-8 autoantibody has been recently recognized as a potent modulator of IL-8 function. In the current study, the concentrations of IL-8 and its autoantibody in gingival crevicular fluid from patients with chronic generalized periodontitis were compared to those in gingival crevicular fluid from patients with refractory chronic periodontitis. Gingival crevicular fluids were collected from patients treated in a private periodontal clinic. Nine patients who were identified as having chronic generalized periodontitis and four with refractory chronic periodontitis were selected for the study. Patients included in the latter group had undergone supportive periodontal therapy for more than 10 years, and during that time had experienced many episodes of periodontal destruction. The gingival crevicular fluid concentrations of total protein, IL-8, free anti-IL-8 autoantibody and IL-8 bound to the autoantibody (anti-IL-8:IL-8 complexes) were examined. There were no differences in concentration of total protein, but significantly higher levels of IL-8 were detected in patients with chronic generalized periodontitis in comparison to patients with refractory chronic periodontitis (P < 0.05). In addition, anti-IL-8:IL-8 complexes were present in 90% of patients with chronic generalized periodontitis, but in only 50% of patients with refractory chronic periodontitis. The results suggest that elevated concentrations of free and complexed IL-8 can differentiate patients with chronic generalized periodontitis from patients with refractory chronic periodontitis.