HLA-Identical Sibling Renal Transplant Tolerance

Inclusion Criteria: * Patient fully informed, signed dated Institutional Review Board (IRB)-approved informed consent form obtained directly by the P.I., Co-P.I., or Res. Nurse, and willing to follow study procedures for the duration of study (3 yrs). * Recipient: a hematocrit of ≥ 33%, and a hemoglobin of ≥ 11.0 g/dL. * Weight \> 40 kg. * Primary renal allograft: living related (HLA-identical donor-recipient sibling pairs) * Negative B-cell and T-cell cytotoxic cross-match, and a low (≤ 10%) Panel Reactive Antibody (PRA) using cytotoxicity. * Women of childbearing potential: negative qualitative serum pregnancy test. * Patients studied equivalently as available for transplant using criteria, w/out regard to gender, race, or ethnicity. * Normal echocardiogram w/ ejection fraction \>50%. * Male participants w/ reproductive potential agree to use approved methods of birth control during treatment w/ Campath-1H and for minimum of 6 months following last dose. Female participants of childbearing potential agree to use approved methods of birth control for duration of participation in study. * Patient agrees to follow-up every 2 months after year 3, up to 10 years. Exclusion Criteria: * Patient previously received/receiving transplant other than kidney. * Patient receiving ABO (blood type) incompatible donor kidney. * Recipient/donor is ELISA positive for human immunodeficiency virus (HIV), antibody positive for hep. C, or surface antigen positive for hep. B. * Patient has current malignancy or history of malignancy (within past 5 years), except non-metastatic basal or squa¬mous cell carcinoma of the skin, or carcinoma in situ of the cervix that has been treated successfully. * Patients w/ significant liver disease, defined as having during past 28 days continuously elevated aspartate aminotransferase (AST (SGOT)) and/or Alanine Aminotransferase (ALT (SGPT)) levels greater than 3 times the upper value of the normal range at this center. * Patient has uncontrolled concomitant infections and/or severe diarrhea, vomiting, active upper gastro-intestinal tract malabsorption or active peptic ulcer or other unstable medical condition that could interfere w/ study objectives. * Patient currently receiving investigational drug or received an investigational drug within 30 days pre-transplant. * Patient currently receiving immunosuppressive agent. * In investigator's judgment, anticipated that patient unable to take medications orally or via nasogastric tube by morning of second day (i.e., skin closure). * Concurrent use of warfarin, fluvastatin, astemizole, pimozide, cisapride, terfenadine, or ketoconazole. * Patient hypersensitivity to tacrolimus, Campath-1H, Thymoglobulin, daclizumab (Zenapax®), sirolimus, MMF or corticosteroids. * Patient pregnant or lactating. * Patients w/ screening/baseline total white blood cell count \<4000/mm3; platelet count \<100,000/mm3; fasting triglycerides \>400 mg/dl (\>4.6 mmol/L); fasting total cholesterol \>300 mg/dl (\>7.8 mmol/L); fasting HDL-cholesterol \<30 mg/dl; fasting LDL-cholesterol \>200 mg/dl. * Patient unlikely to comply w/ visits. * Patient w/ any form of substance abuse, psychiatric disorder or condition that, in investigator's opinion, may invalidate communication. * Expected that tacrolimus cannot be instituted for over 5 days post-operatively. * Patients w/ cytotoxic PRA value \>10% any time pre-enrollment. * Patients w/ Graves disease, unless previously treated w/ radioiodine ablative therapy. * History of idiopathic thrombocytopenic purpura (ITP) or thrombotic thrombocytopenic purpura (TTP)