[Bone and myeloma]

Osteolysis induced by medullary plasmocyte proliferation is related to an increase in the number of osteoclasts in contact with myeloma cells. Osteoclast activating factors (OAF), notably lymphokines such as IL-1 beta, and IL-6, or tumour necrosis factor (TNF), produced by plasmocytes or their microenvironment, have been demonstrated. Bisphosphonates, which are potent anti-osteoclastic agents, are effective during episodes of hypercalcaemia. Their ability to delay the progression of osteolysis is being evaluated.