Though these results did not demonstrate that germinal centers from iMCD patients express more CXCL13 per unit area than germinal centers of RA or reactive lymph nodes, we did find more germinal centers per lymph node section in iMCD than RA and iMCD patients have substantially more enlarged lymph nodes than patients with reactive lymph nodes and RA patients, which could explain the increased circulating levels17. This evidence concerns the gene CXCL13 and rheumatoid arthritis.