After complete islet graft loss is determined, patient's maintenance immunosuppression (i.e. sirolimus, tacrolimus, MMF and/or Myfortic®) will be discontinued and they will be monitored for 10 years thereafter, for the appearance of allosensitization using panel reactive antibody (PRA) levels and monitor the persistence of elevated PRA levels. Primary objective is to determine the rate of allosensitization in patients 3 years after failed islet transplantation (i.e. stimulated c-peptide <0.3mg/mL) and monitor the persistence of elevated PRA levels (≥ 20%) at year 3, 6, and 9. Timing, frequency and level of change in PRA will be monitored after all immunosuppression is discontinued.