PSMB9 and rheumatoid arthritis: Overexpression of PSMB8 and PSMB9 in SLE and RA patients may aggravate the inflammatory response and tissue damage, increase the activation of the PI3K/Akt/mTOR and NF‐κB signalling pathways and enable the release of proinflammatory cytokines TNF‐α and IL‐6 [18, 57].