PRTN3 and rheumatoid arthritis: As summarized in Table 1, all patients had persistent RA with a median disease duration of 12 years (range 7 to 20 years) and were positive for RF-IgM and ACPA-IgG, with a pre-transplantation median RF-IgM level of 836 IU/ml (range 61 to 1,796 IU/ml) and ACPA-IgG level of 484 AU/ml (range 94 to 1,584 AU/ml).