PRTN3 and rheumatoid arthritis: Association of DRB1 with ACPA(+)RA was confirmed (S1 Table), as reported in the previous study [7]; DRB1*04:05 and *04:01 were associated with the susceptibility of ACPA(+)RA and DRB1*04:06, *08:02, *08:03, *13:02, and *14:03 were protectively associated.