Ovaryectomy in nude mice deficient in T cells does not induce bone loss, no osteoporosis occurs after the transplantation of T cells in TNF-deficient mice, and bone loss is induced after the transplantation of wild-type mouse T cells, also demonstrating that the presence of TNF-α producing T cells is crucial for the effects of bone or joint metabolism abnormalities after estrogen deficiency (72). Here, TNF is linked to osteoporosis.