Tumour necrosis factor superfamily cytokines and the pathogenesis of inflammatory osteolysis.

Periarticular osteolysis is a debilitating complication of inflammatory arthritis. While controversy exists as to whether pannus, itself, is capable of degrading bone, the osteoclast is clearly the principal, if not exclusive, bone resorptive cell in rheumatoid disease and other osteopenic disorders. Thus, the treatment of inflammatory osteolysis depends upon understanding the means by which the osteoclast resorbs bone, and the mechanisms that govern its differentiation from precursor cells.