PRTN3 and rheumatoid arthritis: Authors such as Muñoz-Atienza et al. [63] have indicated that the citrullinated P. gingivalis proteome does not contain strongly immunogenic epitopes targeted by serum ACPA during the early stages of RA in this group of patients with established RA with more than 2 years of evolution, as no significant association was found between the diagnosis of RA with high anti-PPAD titers, which agrees with our results.