This generates inflammation, and again, TNF-α and IL-1β are essential for the development of arthritis.217 Notably, both these cytokines stimulate adrenal GC output218 and upregulate 11β-HSD1 activity in synovial fibroblasts and osteoblasts219,220 making these models valuable in understanding the role of endogenous GCs in RA. This evidence concerns the gene TNF and rheumatoid arthritis.