TNF and rheumatoid arthritis: Fibroblast-like synoviocytes (FLS) play a crucial role in these pathological courses.105–107 Three stages of RA progression are reported and include a non-specific inflammatory stage, amplified by T-cell activation in the synovium, the chronic inflammatory stage, and a tissue damage stage mediated by cytokines like IL-1, IL-6, and TNF-α, respectively.108–111