Another important inflammatory signaling protein is interleukin-6 (IL-6), which plays a central role in RA by driving chronic joint inflammation, promoting synovial hyperplasia and pannus proliferation via endothelial growth factor (VEGF), stimulating B and T cell activation leading to autoantibody production, enhancing osteoclast-mediated bone erosion, contributing to systemic manifestations such as fatigue, anemia, and elevated acute-phase proteins (by promoting CRP production in hepatocytes). Here, IL6 is linked to anemia (phenotype).