Interaction between osteoblastic and hematopoietic cell lineages. Abbreviations: CLP, common lymphoid progenitor; CMP, common myeloid precursor; GMP, granulocyte–macrophage progenitor; HSC, hematopoietic stem cell; MKEP, megakaryocyte-erythroid progenitor; MPP, multipotential progenitor; MSC, mesenchymal stem cell; NK, natural killer. Reprinted from Lorenzo J, et al. (2008) Osteoimmunology: interactions of the bone and immune system. Endocr Rev 29:403–440. Copyright 2008 [1]