A closer look revealed a consistent positive correlation between the severity of chronic periodontitis, RA activity, and serum r2 = 0.71 ACPA concentrations (r1 = 0.81, p1 = 0.001, p2 = 0.002, respectively): the higher the RA activity and ACPA levels, the higher the PPD severity, with advanced CAL and tooth loss. The gene discussed is PRTN3; the disease is periodontitis.