We estimate that we will find at least 50 subjects with diagnostic CAN/IFTA histology (Banff 1-2) between the 3 months and 12 months post transplant protocol biopsies based on a 50% incidence in the literature and our own experience. We also estimate that there will be 10% (10 subjects) incidence of clinical rejection by the end of 12 months identified initially by an acute rise in the serum creatinine and confirmed by a biopsy. Lastly, we estimate a 10% (10 subjects) incidence of subclinical acute rejection with stable renal function detected by the protocol kidney biopsies.