Transplantation Bone Disease Induced by Non-Steroid Immunosuppressants

Publisher Summary This chapter focuses on the effect of drugs other than glucocorticoids on bone. The recognition and identification of the role of T lymphocytes and B lymphocyte in mediating the immune reaction involved in virtually every disease, including organ transplantation, allowed development of the class of drugs termed “immune modulators.” These drugs either enhance or suppress the immune reaction depending upon what type of modulation is required to affect the disease outcome. These drugs include the calcineurin inhibitors (CIs) cyclosporine and tacrolimus and the non-CIs rapamycin, mycophenolate mofetil, methotrexate, and azathioprine. These immune-modulating drugs have had an enormous impact on prolonging the lifespan of patients but it adversely affects the bone. The non-steroidal immunosuppressants belonging to the calcineurin inhibiting family have been shown, experimentally and clinically, to produce severe and rapid high-turnover bone loss. Other immunosuppressants, such as sirolimus, azathioprine, and mycophenolate mofetil have not yet been clearly demonstrated experimentally to have adverse effects on bone. A development of immunosuppressant drugs that can prevent organ rejection and other adverse side effects, including bone loss would be a major advancement in the field of organ transplantation.