IL6ST and periodontitis: Therefore, the aim of the present study is to compare periodontal parameter values and serum levels of IL‐6, sIL‐6R, soluble gp130 (sgp130), serum amyloid A (SAA), TNF‐α, IL‐17, and total immunoglobulin G (IgG) in patients with RA and periodontitis before and after TCZ therapy.