The major issue in kidney transplantation remains the suppression of allograft rejection. Immunosuppressant decrease both donor-specific responsiveness and the risk of rejection in the months after transplantation and are maintained. The current immunosuppressant medications, although potent against short-time graft complications including acute renal rejection but are still less effective to ensure long-term graft survival. Also, immunosuppressive medications are associated with cumulative side effects, including increased risks of heart disease, infection, cancer, and diabetes. The important element is that the response of the host T cells becomes less to donor antigens when antigen persists, and immunosuppression is maintained. The antigen persistence with inadequate co-stimulation triggers adaptations that limit T-cell responsiveness. Therefore, the key to successful allograft function is the development of an immunosuppressive medication that suppresses the target cells, which in turn suppresses the cumulative side effects associated with currently available immunosuppressants.

Regulatory T cells may also be able to control allo immune responses, by analogy with their ability to suppress autoimmunity. The main goal of immunosuppression is to induce tolerance by preventing allograft loss without the consequences of infection or toxicity and, most importantly, to achieve a long-term graft result. There are several studies explaining the role of regulatory cells in the prognosis, diagnosis, and treatment of kidney transplant recipients. While several types of regulatory lymphocyte populations have been described, CD4 T cells expressing the Foxp3 transcription factor (Foxp3+ Tregs) are the best understood. Foxp3+ Tregs constitute 5 to 10% of peripheral CD4+ T cells in both mice and humans and are critical for maintaining immune homeostasis. Evidence exists that Tregs expand after peri transplantation lymphopenia, inhibit graft rejection, and induce and maintain tolerance. Reducing the dosage of current immunosuppressants or combination therapy with the Tregs may eliminate the long term side effects of immunosupressants.

Kidney transplantation, Allograft function, Allograft rejection, Immunosuppression, Regulatory T cells