Levels of interleukin-21 in patients with untreated chronic periodontitis.

Background: A growing body of evidence suggested that interleukin (IL)-21 enhances the effector phase during T-cell responses. The aim of our study is to determine the levels of IL-21 in periodontal sites from patients with chronic periodontitis and controls.
Methods: The population studied consisted of 34 patients (15 with chronic periodontitis and 19 healthy patients). Twenty samples (10 gingival crevicular fluid [GCF] and 10 gingival biopsies) were collected from each group before the patients with periodontitis received periodontal treatment. Total protein concentrations were measured in all samples; the presence of IL-21 was confirmed by immunohistochemistry and Western blot, and IL-21 levels were quantified through an enzyme-linked immunosorbent assay. Statistical analyses were performed using statistical software. Data were expressed as patient means ± SDs or medians (interquartile ranges) by using the χ(2), Student t, and Mann-Whitney U tests.
Results: GCF IL-21 was mainly detected in patients with chronic periodontitis (P <0.05). Levels of IL-21 in gingival tissues were significantly higher in patients with chronic periodontitis compared to healthy individuals (P <0.05). The Western blot and immunohistochemical staining confirmed the presence of IL-21 in periodontal tissues and GCF.
Conclusion: IL-21 was highly expressed in patients with chronic periodontitis, especially in gingival biopsies; therefore, IL-21 might play a role in the T-cell response.