IL-6 levels in GCF (pg/site) were elevated for both Stage I-II (590.30 (93.86) pg) and III-IV (759.20 ± (318.00) pg) groups as compared to the healthy group (513.90 (223.70) pg) at baseline, although statistically significant differences were only found for Stage III-IV periodontitis (p < 0.01). Here, IL6 is linked to periodontitis.