For the 167 immune-related DEGs between KBD and RA, we identified one up-regulated MAPK signaling pathway involving 15 up-regulated genes, and 7 down-regulated signaling pathways involving 152 down-regulated genes (P<0.05), which included toll-like receptor (TLR) signaling pathway, janus kinase-signal transducers and activators of transcription (JAK-STAT) signaling pathway, leukocyte transendothelial migration, NOD-like receptor signaling pathway, T-cell receptor signaling pathway, chemokine signaling pathway, and antigen processing and presentation (Table 2). This evidence concerns the gene SOAT1 and rheumatoid arthritis.