IL‐23/IL‐17 axis and soluble receptors isoforms sIL‐23R and sIL‐17RA in patients with rheumatoid arthritis‐presenting periodontitis

BACKGROUND: Rheumatoid arthritis (RA) and periodontitis (P) are chronic inflammatory diseases characterized by joint and radiographic bone loss, respectively. IL‐23 and IL‐17 have an essential role in the immunopathogenesis of RA, and P. IL‐23 stimulates Th17 cells through which produces IL‐17, IL‐21, and RANKL. IL‐17 stimulates fibroblasts to produce RANKL, which initiates bone loss in the joints in RA and the periodontal tissue in periodontitis. The aim of this study was to determine the expression pattern of IL‐23/IL‐17 axis and soluble receptors isoforms sIL‐23R and sIL‐17RA of patients with RA presenting P (RAP). MATERIAL AND METHODS: Healthy subjects (HS) (n = 42), patients with P (n = 40), RA (n = 20), and patients with RAP (n = 40) were included. Plasma samples were obtained to evaluate the IL‐23, IL‐17A, sIL‐23R, and sIL‐17RA by ELISA technique. A nonparametric Mann‐Whitney U test was used to compare the differences between groups. A Chi‐square was used to compare gender, grade and stage of periodontitis, and DAS28‐ESR between the groups. Spearman's rank correlation coefficient was used to study the association between the molecules and clinical parameters. RESULTS: IL‐23 levels were increased in the RAP group, and lower sIL‐23R levels were found in the RAP groups. However, IL‐17A was lower in the P and RAP group but not in RA patients. RAP group showed a decrease IL‐17A levels in advanced stages of the periodontal disease. CONCLUSION: These results suggest that IL‐23 and IL‐17A tend to downregulate their expression patterns when patients present both rheumatoid arthritis and periodontitis.