According to the 2010 diagnosis criteria for rheumatoid arthritis published by the European League Against Rheumatism, RA is classified into four domains including joint involvement (score range of 0–5 points, based on the number of inflamed large/small joints), serology (score range of 0–3 points, based on negative/strong/weak positive RF and anti-CCP or ACPA), acute-phase reactants (score range of 0–1 points, based on normal/abnormal CRP and ESR), and symptom duration (2 levels; score range of 0–1 points, based on whether the duration is less or more than 6 weeks). Here, PRTN3 is linked to rheumatoid arthritis.