PRTN3 and rheumatoid arthritis: PR patients had a lower frequency of some IgG ACPA fine specificities than RA patients, which was significant for the two vimentin-derived peptides, p48 vimentin (1.9% RP vs. 14.8% AR, p = 0.03) and, especially, p55 vimentin (PR 24.1% vs. 59.3% RA; p < 0.001) (Table 2).