Transplant recipients have to take anti-rejection medications to prevent their immune systems (the body's natural defense system against illness) from rejecting their new organs. Most patients who receive a transplanted organ must take these anti-rejection medications for the rest of their lives, or for as long as the transplanted organ continues to work. Taking standard anti-rejection medications for a long time can cause serious side effects, including pancreas and kidney damage. There would be a benefit to finding new anti-rejection medications that work just as well, but could lessen the amount of anti-rejection medications that are taken long term.