CD4 and osteoporosis: One month after the infusion, the typical trabecular bone resorption and lumbar BMD reduction were observed in OVX-immunocompromised mice that received CD4+CD25−CD45RB+hi T cells, but not CD4+CD25−CD45RB−/low T cells (Fig. 2C), suggesting that CD4+CD25−CD45RB+hi T cells were responsible, at least in great part, for T-cell-associated osteoporosis.