In RA, excessive RANKL is produced by synovial fibroblasts stimulated by TH17 cell-derived IL-17.44 In SLE patients, the soluble RANKL level is significantly increased in the serum.45 The upregulated RANKL in these autoimmune diseases accelerates the fusion of preosteoclasts. Here, TNFSF11 is linked to systemic lupus erythematosus.