Interleukin-22 (IL-22) Gingival Gene Expression and GCF Concentration in Periodontal Health and Disease

IL-22 is a cytokine that is assumed to improve anti-microbial defense of epidermal and epithelial cells and the cells of gastrointestinal and respiratory systems. With respect to absence of enough relevant articles in this regard the aim of this study was to evaluate the correlation between IL-22 gene expression in gingival tissues as well as its concentration in GCF and periodontal diseases. Gingival samples obtained from 60 patients of three different groups (healthy, gingivitis and chronic periodontitis) and used for evaluation. Expression of IL-22 mRNA was measured by Real-time PCR and its concentration in GCF was determined by ELISA. In none of the tissue samples, mRNA of IL-22 was detected; However IL-22 concentration was significantly higher in periodontitis in comparison to other groups and in gingivitis was higher than the normal gingiva. There was no relationship between concentration of IL-22 in GCF and the extent and severity of chronic periodontitis. With respect to the results of this study, probable systemic production of IL-22 in response to periodontopathic bacteria is suspected and it is assumed to counteract with LPS of these bacteria and protect periodontal tissues against adverse effects that results from stimulation of different cells and molecules of immune system by LPS.