• INCLUSION CRITERIA:

Candidates for a kidney or combined kidney-pancreas transplant performed at the National Institutes of Health, or non-uremic healthy volunteers who are not on immunosuppressive medications.

Previous recipients of kidney or combined kidney-pancreas transplants.

Recipients of kidney or combined kidney-pancreas transplants interested in participation in the Recurrent Disease Allograft Registry.

Willingness and legal ability to give informed consent or permission from a legal guardian.

Willingness to travel to the Clinical Center for protocol specific samples to be taken, or in some cases, the ability to send samples via overnight mail.

For transplant patients, availability of donor tissue for testing. This could include splenic or peripheral blood lymphocytes from a cadaveric donor or a willing living donor enrolled on the Clinical Center Living Donor Protocol who consents to periodic phlebotomy for peripheral blood lymphocyte isolation.

EXCLUSION CRITERIA:

Inability or unwillingness to comply with protocol monitoring and therapy, including, among others, a history of noncompliance, circumstances where compliance with protocol requirements is not feasible due to living conditions, travel restrictions, access to urgent medical services, or access to anti-rejection drugs after the research protocol is completed.

Any active malignancy. Patients with primary, cutaneous basal cell or squamous cell cancers may be enrolled providing these are appropriately eliminated prior to transplant.

Significant coagulopathy or requirement for anticoagulation therapy that would contraindicate protocol allograft biopsies.

Platelet count less than 100,000/mm(3).