It’s now nine years since the “Workshop on Bone and the Hematopoietic and Immune Systems,”
sponsored in August 1997 by the NIAMS and several other components of the NIH (Sharrock
1998). Even in 1997, although no one had yet coined the term “osteoimmunology,” it was not
original to suggest that the skeleton and the immune system might share regulatory pathways
or interact with one another directly. The possibility had been raised many times in papers
and reviews over a number of years. After all, osteoclasts originate in the monocyte-macrophage
lineage, and osteoblasts cohabit with immune cell lineages in the bone marrow. It was also
tempting to see significance in such observations as the deleterious effects of immunosuppressants
on bone, immune deficiencies in osteopetrosis, or the ubiquity of interleukins and other
immune-related cytokines in the pathways that regulate bone remodeling. But suggestions are
no substitute for hard evidence, and in 1997 the latter was still in short supply. Reports were
scarce, seldom definitive, and often conflicting.