Given that osteoclasts derived from early arthritis patients express VPAC receptors and VIP opposes the osteoclastogenic effects of M-CSF and RANKL and reduces bone resorption in vitro, we hypothesized that the VIP/VPAC receptors axis, through the action of endogenous VIP, may be involved in bone function. This evidence concerns the gene TNFSF11 and Arthritis.