TNFSF11 and systemic lupus erythematosus: The stronger inhibitory effects of lupus IgG on RANKL-mediated osteoclastogenesis were presented in cells pre-treated for 24 hours when compared with cells treated with both RANKL and lupus IgG at the same time; at 24 hours after RANKL stimulation, the inhibitory effect of lupus IgG on osteoclastogenesis was eliminated (27).