TNFRSF11B and rheumatoid arthritis: Quinn et al. [6] and Takayanagi et al. [22] were able to show that, in contrast to unstimulated co-cultures (skin fibroblasts [6] or synovial fibroblasts from patients with rheumatoid arthritis [22] and PBMCs), the addition of 1,25(OH)2VitD3 and Dexamethasone or 1,25(OH)2VitD3 and MCSF respectively lead to an increased RANK-L/OPG ratio.