[Introduction to osteoimmunology]

Since research into the bone destruction in rheumatoid arthritis led us to realize the importance of the interplay of the immune and skeletal systems, interdisciplinary research field called osteoimmunology has attracted further attention. This is partly based on the identification of a number of unexpected bone phenotypes in mice lacking immunomodulatory molecules. Accumulating evidence suggests that the immune and skeletal systems share not only cytokines but also various signaling molecules, transcription factors and membrane receptors. This emerging field will be increasingly important not only for the future strategy for rheumatic diseases but also for clinical and basic studies in all the related fields.