New immune connections in osteoclast formation.

Osteoimmunology is an interdisciplinary research field that investigates the interplay of the skeletal and immune systems at the molecular level. The interaction between immune cells and osteoclasts has been a major topic in this field. As osteoclasts are derived from the monocyte/macrophage lineage, the macrophage-osteoclast interaction has long been studied. The T cell-osteoclast interaction has also attracted much attention in the study of bone destruction in arthritis. In addition, recent reports have revealed new players linking osteoclasts and other immune cells, including B cells and dendritic cells. Thus, a large number of molecules are in fact shared by osteoclasts and immune cells. These findings will lead to a better understanding of the pathogenesis of diseases affecting both systems and will provide a molecular basis for novel therapeutic strategies.