Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown origin. It involves multiple organs including the joints, skin, kidneys and central nervous system. The disease process is caused by a dysfunction of the immune system. The drugs currently used for the treatment of SLE are only partially effective and carry significant risks for side-effects. Rapamycin, also called sirolimus or Rapamune, has been approved by the FDA to prevent rejection of organ transplants at daily doses of 2 mg to 8 mg. Patients that were resistant or intolerant to conventional medication have been effectively treated with Rapamycin and were able to decrease the amount of prednisone they needed.