The purpose of this study is to compare two different ways of monitoring the immune system to determine how to manage the doses of anti-rejection medications.

This is a single center randomized controlled trial investigating the efficacy and safety of adjusting calcineurin inhibitor (CNI) dosing based on Nuclear Factor of Activating T Cells (NFAT)-dependent cytokine gene expression as compared to standard of care adjustments based on trough level. Before any study-related evaluations are performed, the patient must give written informed consent. Once consent is obtained, a patient's eligibility to participate in the study will be assessed within 4 weeks of their 6 month management biopsy. Approximately 40 patients who meet inclusion criteria will be randomized at University of California, San Francisco (UCSF). Eligible patients include any patient maintained on triple therapy with tacrolimus, mycophenolate mofetil ,and prednisone who has had no prior rejection episodes and who has undergone a 6 month management kidney biopsy that shows no evidence of acute cellular rejection or antibody mediated rejection.

Inclusion Criteria: Eligible patients include any patient maintained on triple therapy with tacrolimus, mycophenolate mofetil ,and prednisone who has had no prior rejection episodes and who has undergone a 6 month management kidney biopsy that shows no evidence of acute cellular rejection or antibody mediated rejection.

Exclusion Criteria: Any patient not maintained on triple therapy with tacrolimus, mycophenolate mofetil and steroids and/or who had evidence of rejection on 6- month management biopsy.