Interleukin-4 And Interferon-r in Chronic Periodontitis

Objectives: Recent studies have shown that cytokines, especially those produced by T cells, are pivotal to the immune response of chronic periodontitis (CP). The aim of the present study was to determine the levels of IL-4 and IFN-γ in GCF of individuals with moderate to advanced CP and to study their associations with clinical periodontal parameters, smoking, and the response to non-surgical periodontal treatment (NSPT). Materials and Methods: A total of 70 sites from 17 patients with CP were included in the study. GCF was collected by means of Periopaper® at baseline and one month after NSPT. Commercially available ELISA produced by R&D Systems Inc. measured IL-4 and IFN-γin 140 samples. Results: Before NSPT, the level of IL-4 was (1) significantly higher in sites without bleeding on probing (BOP) than sites with BOP, (2) significantly higher in sites with probing depth (PD) <6mm and sites with probing attachment level (PAL) <6mm than sites with PD≧6mm and PAL ≧6mm in smokers. Furthermore, in sites with PD≧6mm and PAL≧ 6mm, the level of IL-4 in non-smokers was significantly higher than those in smokers. After NSPT, the clinical parameters were significantly improved, while the total amount of GCF IFN-γ was significantly lower and the IL-4/IFN-γ ratio was significantly higher than before NSPT. The response to NSPT in the smoking population was similar to that found in the non-smoking population. Conclusion: IFN-γ (the Th1 cytokine) may be predominant in diseased sites, whereas IL-4 (the Th2 cytokine) may reduce local inflammation. The high ratio of IL-4/IFN-γ may be related to the improvement of clinical periodontal health. The GCF IL-4 seemed to be suppressed in smoking periodontitis patients. (Grant NSC 94-2314-B-037-010, Taiwan).