Delayed/slow graft function is the most common complication after kidney transplantation with an incidence over 20% and is the result of ischemia-reperfusion injury. The increased use of marginal kidney grafts to palliate the organ shortage is leading to a continued rise in the incidence of delayed/slow graft function. Delayed/slow graft function, however, is associated with an increased risk of acute rejection and graft failure. There are currently no clinically accepted biomarkers and no specific treatments for delayed/slow graft function. Regulatory T cells are protective in ischemia-reperfusion injury and rejection by suppressing pathologic immune responses. We hypothesize that the pre-transplant measurement of highly suppressive regulatory T cell is an accurate biomarker for delayed/slow graft function and its immunologic consequences. Ultimately, marginal kidney graft allocation could be directed to regulatory T cell-robust recipients and regulatory T cell-directed therapies could decrease marginal kidney graft discards without increasing delayed/slow graft function or impacting outcomes.

Inclusion Criteria:

- Adult kidney transplant candidates immediately prior to their kidney transplant surgery

Exclusion Criteria:

• < 18 years old
• Active immunosuppressive drug use
• Hepatitis C
• HIV

Kidney transplant recipients