PRTN3 and rheumatoid arthritis: On the other hand, in line with our results, Ching-Tsai Lin et al. found that IgM isotype RF positivity was negatively associated with drug survival (HR=0.48, 95%CI[0.27–0.85], p=0.013).21 Mulligen et al. also agreed with these results.22 This could be explained by the fact that RF- and ACPA-negative RA generally show less bone erosion, structural damage, and disease progression.23 Thus, the presence of these autoantibodies could be associated with a more aggressive disease responding less to bDMARDs.