Also, Mikuls et al. measured the antibodies in blood and Porphyromonas gingivalis and found that RA patients and patients with positive ACPA in the blood (anti-citrullinated protein antibodies) had a higher incidence in the PD diseases [10]. Lappin et al. in the ELISA study showed that 6 months after the development of the PD, significant changes in the anti-cyclic citrullinated and anti-Porphyromonas gingivalis titres were observed [16]. The gene discussed is PRTN3; the disease is rheumatoid arthritis.