[Osteoclast differentiation and activation].

In autoimmune arthritis, activation of T cells induces bone destruction through receptor activator of NF-kappaB ligand (RANKL) . Recent study revealed interleukin-17 (IL-17) -producing helper T cell subset (Th17) , but not IFN-gamma-producing Th1, to be responsible for bone destruction. Here we summarize the current understanding of osteoclast differentiation and activation in the context of osteoimmunology.