There were 21 DEGs shared in both the RA and T2D groups, which were also involved in the 10 shared pathways: CYP4F3↑, DEFA4↑, DEFA1↑, MMP8↑, MMP9↑, MT2A↓, ITGB4↓, RBP1↓, SNAI1↓, ARG1↑, MPO↑, LTF↑, C4BPA↑, MYL4↑, HLA-DQA2↑, CA1↑, SELENBP1↑, BPI↑, CD177↑, CA4↑, and BMX↑. Here, HLA-DQA2 is linked to rheumatoid arthritis.