Comparison of interleukin-21 levels and its correlation with clinical parameters among healthy individuals, chronic periodontitis, and aggressive periodontitis patients

Interleukin-21 (IL-21) has both anti- and pro-inflammatory roles associated with chronic inflammation. It causes tissue destruction by increasing pro-inflammatory cytokines and curbs the activity of certain immune cells that evoke an anti-inflammatory role. The aim of this study was to compare IL-21 levels in gingival crevicular fluid among patients with generalized chronic periodontitis (GCP), aggressive periodontitis, and healthy gingiva (HG) and to correlate IL-21 levels with clinical parameters. In this cross-sectional case-control study, 60 subjects were categorized into three groups: HG ( =20), generalized aggressive periodontitis (GAP; =20), and GCP ( =20). IL-21 was measured using ELISA and results were correlated with clinical parameters including plaque index, gingival index, periodontal probing depth (PPD), and clinical attachment level (CAL). Mean IL-21 levels were 20.0±0.7 in HG, 25.9±0.9 in GCP, and 25.3±1.1 in GAP groups. Significant differences in IL-21 levels were found between HG versus GAP (