All protein levels that were upregulated in RA, were significantly and positively correlated with the histological inflammatory score (HIS) (Table 1): LAP3 (r = 0.77, P < 0.0001), DNAJB11 (r = 0.77, P < 0.0001), MANF (r = 0.79, P < 0.0001), LCP1 (r = 0.74, P < 0.0001), CTSZ (r = 0.69, P = 0.0002), PTPRC (r = 0.68, P = 0.0004) and EML4 (r = 0.78, P = 0.0001). Here, PTPRC is linked to rheumatoid arthritis.