Novel Noninvasive Assays to Predict Transplantation Rejection and Tolerance: Enumeration of Cytokine-Producing Alloreactive T Cells

Treatment and prevention of allograft loss in organ transplant recipients relies chiefly on non–antigen-specific immunosuppression. Current approaches to the management of these immunosuppressive drugs are largely empiric and reactive because of lack of immune monitoring assays. Alloreactive T cells play a key role in acute rejection and in development of chronic allograft nephropathy, the leading cause of late allograft failure. There is thus an increasing interest in development of simple, reliable, noninvasive assays measuring allogeneic anti-donor responsiveness or donor-specific nonresponsiveness to predict ransplantation rejection and tolerance. Because the frequency and cytokine profile of alloreactive T cells play an important role in these processes, this article mainly focuses on assays that enumerate cytokine-producing alloreactive T cells.