Of the models listed in Table , only investigates the dynamic effect of multiple immune cells in bone remodeling. The work includes a three-compartment physiologically based PK model for differentiating naïve CD4+ T cells into regulatory T cells in the gut, blood, and bone. These regulatory T cells then influence TGF-β production in the bone and induce Wnt-10b production. The physiologically based PK model is then linked to a bone remodeling model that includes the local effects of systemic changes in Wnt-10b . Since this is the only mathematical description of nonlocal immune effects on bone dynamics, significant opportunities remain for future research to explore multi-organ systemic interactions between the skeletal and immune systems.