In blood CD14+ cells of RA patients, the MetSig included the expression of ATP5BP, COX7A2, PSMB6, PSME3, GTF3C6, and GTF2E2 genes, which individually correlated to CDC42, and together identified the patients where clinical RA disease activity was dependent on the CDC42-related MetSig of CD14+ cells. Here, PSMB6 is linked to rheumatoid arthritis.