Fibroblast-like synoviocytes (FLS), which are dominant cells at the pannus-cartilage junction, produce different inflammatory mediators in RA patients, and some reports have indicated that GM-CSF production can be triggered by human chondrocytes and synovial fibroblasts (FLS) in response to IL-1 and TNFa (23, 24). The gene discussed is CSF2; the disease is rheumatoid arthritis.