After we compared the staining patterns of the slides prepared from RA and non-RA (diagnosed as not RA) patients, we determined that our clone A-s1 antibody (alpha chain-specific, referred to hCitFbg-α-Ab) detected CitFbg without cross-reaction for massive Fbg/fibrin, while the clone F antibody did not (Fig. S4a). This evidence concerns the gene PSMD1 and rheumatoid arthritis.