The major aim of this research study is to investigate the relationship between genetic variation in DNA (inherited code material in the cells of the body) and factors affecting transplant outcomes, like the drugs people receive or the way their immune systems work, for example. To do this, investigators will collect blood samples from participants. Genetic material will be separated from each blood sample and analyzed, looking for genetic variation.

In the past, the major problems in kidney transplantation were surgical complications, acute rejection, and infections. Right now, researchers are focusing on improving immune suppression therapy and achieving better long-term survival of kidney transplants. One of the ways to try to understand what causes loss of function after many years is to find out if there is a genetic factor involved.

There are a number of differences in specific genes that have been identified and are thought to affect transplant outcomes. Studying these gene variations (differences between people or differences between populations) is important in determining whether these variations are related to transplant outcomes and how this information can help patients achieve better long-term transplant survival.

Inclusion Criteria:

• Kidney (or kidney-pancreas) transplant recipient no more than 10 days post-transplant or kidney donor no more than 30 days post-transplant or previously enrolled in Phase I of the Genomics of Kidney Transplantation Study;
• No organs other than kidney or pancreas transplanted simultaneously with the qualifying kidney transplant; and
• Participant or parent/guardian must be able to understand and provide written informed consent.

Inclusion for the Activity and mRNA Expression Cohort:

• Recipient enrolled in the Main Cohort Study;
• Informed consent for participation in the Activity and mRNA Expression Cohort;
• Age 18 years or greater as of day of transplantation;and
• Will receive tacrolimus, cyclosporine or mycophenolate as part of maintenance immunosuppression therapy.

Exclusion Criteria:

- Inability or unwillingness of the participant or parent/guardian to give a written informed consent or comply with the study protocol.

For the Activity and mRNA Expression Cohort:

- Inability or unwillingness of the participant or parent/guardian to give a written informed consent for participation in the Activity and mRNA Expression Cohort or comply with the study protocol.

Targeted: 3000 Kidney or Kidney-pancreas transplant recipients and 1300 of the donors