Minimization of immunosuppressive therapy and immunological monitoring of kidney transplant recipients with long-term allograft survival

Abstract

Incidence of cardiovascular complications, cancers and chronic allograft nephropathy (CAN) suggests reduction of immunosuppressive dosages. Some studies analyzed the effects of minimization of immunosuppression until the avoidance of immunosuppressive drugs. However minimization seems to be related to a higher incidence of acute rejection. Induction of tolerance after transplantation and use of immunological tests that could monitor the immune reactivity are required. The aim of this study is to evaluate immunological state in a group of recipients after deceased and living donor kidney transplantation and to minimize immunosuppressive therapy monitoring simultaneously clinical and immunological parameters. We analyzed 41 patients, 38 from deceased donors and 3 from living donor kidney transplantation. All patients were treated with triple immunosuppressive therapy: cyclosporine or sirolimus or tacrolimus, mycophenolate mofetil and steroids. In all recipients the presence of CD8+CD28- T suppressor cells (Ts) was analyzed. Patients were divided in 2 groups, according to the presence of Ts. In patients with Ts, (Group A, n=19), mycophenolate mofetil (MMF) was progressively reduced and then stopped. Steroids were subsequently reduced and then interrupted, maintaining an immunosuppressive therapy with low doses of calcineurin inhibitors (CNI) or sirolimus (SIR). 22 patients were without presence of Ts: we enrolled for the study only patient acute rejection free, without proteinuria and with creatinine levels stable (Group B, n=19). In these patients, MMF was reduced and then stopped, while steroids were decreased to 5 mg at alternate days, maintaining CNI or SIR at medium therapeutic dosages (minimized therapy). Patient and graft overall survival in Group A and in Group B were respectively at 100% and 94.7%. Incidence of acute rejection was respectively at 0% in group A and 15.7% in Group B. Presence of episodes of acute rejection in Group B confirms risk of later minimization of steroids and the relevance of the analysis of recipient immunological reactivity before modification of immunosuppressive therapy. A careful evaluation of recipient immune reactivity with the presence of T regulatory cells can allow adequate and personalized immunosuppressive regimens, without high risks of acute rejection.