Key pro-inflammatory cytokines, including IL-1, IL-6, IL-15, IL-17, TNF-α, and granulocyte macrophage–colony stimulating factor (GM-CSF), are elevated in the synovial fluid and serum of RA patients, contributing to synovial inflammation, cartilage destruction, and bone erosion [45]. The gene discussed is IL17A; the disease is rheumatoid arthritis.