For etanercept studies, 6-month-old FcγRIIb-/- males and WT controls were subcutaneously injected with 16 doses of either PBS or 25 mg/kg etanercept (Enbrel, Wyeth, New Jersy, USA) which is an intermediate dose twice a week for 8 weeks [16]. At the end of the experiment, blood samples were collected, centrifuged at 10,000 rpm for 10 minutes and kept at −80°C for determination of serum proinflammatory cytokines and PTH levels. Left mandibles were fixed in 10% neutral buffered formalin for μCT analysis. Right mandibles were frozen in liquid nitrogen and kept at −80°C for RNA isolation and qPCR.