HSPA1A and rheumatoid arthritis: Differential expression of PADI2 (Fig. 4D), HLA-DPB1 (Fig. 6B), HLA-A (Fig. 7A), HSPA1A (Fig. 7B), MICB (Fig. 7C) and TRAF1 (Fig. 7D) in PBMCs between RA cases and controls was also found according to our in-house data (P = 3.21 × 10− 2, 1.42 × 10− 2, 9.83 × 10− 6, 3.40 × 10− 6, 1.94 × 10− 4 and 1.98 × 10− 2, respectively).