Indeed, we found that affinity-purified autoantibodies against citrullinated vimentin from RA patients, but not ACPA-depleted serum IgG were able to enhance osteoclastogenesis and bone resorption in ex vivo osteoclastogenesis assays as well as in recombination activation gene 1 (RAG1)-deficient mice (52). The gene discussed is RAG1; the disease is rheumatoid arthritis.