PRTN3 and rheumatoid arthritis: Three infectious agents, namely Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Epstein-Barr virus (EBV), are believed to trigger citrullination in RA and thus render citrullinated peptide as potential arthritogenic neoantigens that lead to ACPA production (Fig 1) [8–12].