The hypothesis is that humoral and cellular islet-specific responses are an early risk factor for recurrence of autoimmunity and hyperglycemia in simultaneous pancreas-kidney (SPK) recipients independent of alloimmunity. This study will test the hypothesis and will assess their individual and combined predictive value.

To identify the factors associated with recurrence of diabetes in subjects who received a simultaneous pancreas-kidney (SPK) or pancreas transplant. The study will see if there are changes in the participant's blood that will help the investigator know whether diabetes has returned after the transplant.

SPK patients will be retrospectively analyzed to determine frequency, levels and time course of autoantibody recurrence and predictive value of autoantibodies for recurrence of the disease.

This study will prospectively follow our existing and our new pancreas transplant recipients to monitor autoantibody levels, monitor and phenotype autoreactive T cells in peripheral blood. This will happen monthly for 24 months.

This study will assess the presence or absence of insulitis in the transplanted pancreas from biopsies performed in recipients with consistent recurrence of multiple autoantibodies.

It will also monitor and phenotype autoreactive T cells from the pancreatic infiltrate obtained by pancreatic transplant biopsies.

Inclusion Criteria:

• Patient has been fully informed and has signed a dated IRB approval informed consent form and is willing to follow study procedures for the extent of the study (24 months). Parent or legal guardian must provide written consent for patients <18 years of age.
• Age 18-75 years.
• Recipient of simultaneous pancreas and kidney transplant
• Primary or secondary renal allograft: living or deceased

Exclusion Criteria:

• Patient has previously received or is receiving an organ transplant other than a pancreas-kidney.

Type 1 diabetes who received a simultaneous pancreas-kidney (SPK) transplant