Experimental evidence of the presence of specific types of PLA2s such as sPLA2-IIA, sPLA2-V and sPLA2-X, cPLA-IVA and iPLA2β in chondrocytes arise from analysis of human synovial fluid, especially from RA or OA patients or from the effects of cell stimulation with interleukin-1 (IL-1) and tumor necrosis factor (TNF). The gene discussed is TNF; the disease is rheumatoid arthritis.