The expression of MIF and RANKL in RA human synovial fluid and synovium. (a) Correlation between the levels of MIF and sRANKL in synovial fluids from 16 patients with RA. (b) Immunohistochemical detection of MIF and RANKL in the synovium of patients with RA and OA. All tissues were counterstained with hematoxylin (original magnification 400×). MIF, macrophage migration inhibitory factor; OA, osteoarthritis; RA, rheumatoid arthritis; RANKL, receptor activator of nuclear factor kappa-B ligand.