This is a comparative study to assess the biologic and clinical activity of the agent ustekinumab when given in concert with our established regimen of SIR/TAC. Patients will be randomly assigned between the standard regimen of tacrolimus/sirolimus (TAC/SIR + placebo) vs. the investigational regimen of tacrolimus/sirolimus/ustekinumab (TAC/SIR/U) in a 1:1 scheme.