IL17A and rheumatoid arthritis: Upregulation of SHP2 was reported following IL-17A simulation, and this further activated STAT3 to induce IL-23, granulocyte-macrophage colony stimulating factor, and receptor activator of nuclear factor-κB ligand (RANKL) expression in rat models of rheumatoid arthritis.96 Analysis of synovial tissue biopsies from patients with rheumatoid arthritis showed that CD31 was excluded from the center of the T/B cell synapses.