HLA-Identical Sibling Renal Transplant Tolerance

Primary Study Objectives:

1. To remove all immunosuppressive therapy from recipients of HLA-identical sibling renal
transplants within 24 months of transplantation.

2. To detect and follow cellular (macro) chimerism of donor hematopoietic stem cell (DHSC)
lineages and the generation of T-regulatory cells using specialized immunomonitoring
assays for these donor/recipient pairs to demonstrate specific immunologic
unresponsiveness.

3. To investigate the safety and efficacy of a treatment regimen consisting of induction
therapy with Campath-1H and steroid-free low dose maintenance immunosuppression,
consisting of mycophenolate mofetil (MMF) and tacrolimus converted to sirolimus. This
is to be followed by complete withdrawal of immunosuppression beginning at one year, at
a minimum, post transplant, in recipients who have also been given four infusions of
purified donor hematopoietic Cluster of Differentiation (CD)34+ stem cells (DHSC).

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)