Moreover, levels of IL‐22 and Th22 cells have been found to be elevated in the periphery and synovia of RA patients (24, 25, 26), and IL‐22 has been shown to induce proliferation of synovial fibroblasts and promote RANKL production and osteoclastogenesis in vitro (27). The gene discussed is IL22; the disease is rheumatoid arthritis.