Macrophages, T and B lymphocytes, fibroblasts, and a myriad of pro-inflammatory cytokines, notably interleukin-6 (IL-6) and TNF-α (tumor necrosis factor alpha), in conjunction with prostaglandin E2 (PGE2), are pivotal actors in the intricate pathogenesis of RA, contributing to the hyperplasia of articular cartilage. Here, TNF is linked to rheumatoid arthritis.