Prevention of Acute Rejection after Rescue with Belatacept by Association of Low-Dose Tacrolimus Maintenance in Medically Complex Kidney Transplant Recipients with Early or Late Graft Dysfunction.

BACKGROUND:Increased acute rejection risk in rescue protocols with Belatacept may limit its use particularly in medically complex patients where preexisting increased risk of rejection couples with CNI toxicity.METHODS:Retrospective analysis was performed in 19 KTs shifted to a Belatacept-based immunosuppression with low-dose Tacrolimus (2-3 ng/mL) after evidence of allograft disfunction, including patients with primary non-function (PNF), chronic-active antibody-mediated rejection (cAMR), history of previous KTs and/or other concomitant transplants (liver, pancreas). Evaluation of CD28+ CD4+ effector memory T cell (TEM) before conversion was performed in 10/19.RESULTS:Kidney function significantly improved (median eGFR 16.5 ml/min/1.73m2 before vs 25 ml/min after; p = 0.001) at a median time after conversion of 12.5 months (9.1-17.8). Overall graft and patient survival were 89.5% and 100% respectively. Definitive weaning from dialysis in 5/5 KTs with PNF was observed, whereas 7/8 patients lost their graft within first year in a control group. eGFR significantly ameliorated in re-trasplants (p = 0.001) and stabilized in KTs with other organ transplants or cAMR. No acute rejection episodes occurred, despite the significant risk suggested by high frequency of CD28+ CD4+ TEM in most patients. Opportunistic infections were limited and most common in early vs late-converted.CONCLUSIONS:Rescue association of Belatacept with low-dose Tacrolimus in medically complex KTs is a feasible option that allows prevention of acute rejection and amelioration of graft function.