Graft nephrectomy is associated with massive allo-sensitization following this event. The occurrence of anti-HLA antibodies is a major barrier to perform a second kidney transplantation. Investigators propose here to evaluate in a phase II pilot study, the safety of the use of a single dose of Tocilizumab immediately before or after graft nephrectomy. The primary endpoint evaluated here is the occurrence of serious infectious complications following graft nephrectomy, with a treatment by Tocilizumab. Secondary endpoints evaluated here are - to evaluate all complications after graft nephrectomy, - and the Tocilizumab effectiveness to reduce anti-HLA antibodies at one year post nephrectomy.