Transplant acceptance-inducing cells as an immune-conditioning therapy in renal transplantation.

The transplant acceptance-inducing cell (TAIC) is a type of immunoregulatory macrophage with the capacity to specifically dampen allogeneic rejection responses to a degree allowing safe minimization of conventional immunosuppressive therapy. In the first part of this report, the production and phenotype of the human TAIC is described. In the second part, an analysis is given of the TAIC-I clinical trial, in which 12 recipients of renal transplants from deceased donors were treated with donor-derived TAICs as an adjunct immune-conditioning therapy. Conventional immunosuppression was gradually withdrawn from 10 of these 12 patients over a period of 8 weeks, starting in the fourth week after transplantation. All but two patients tolerated cessation of steroid therapy, while the remaining eight patients were first weaned from sirolimus and then, in six cases, were also weaned to low-dose tacrolimus monotherapy. It is concluded that TAIC therapy is both safe and clinically practicable; however, the TAIC-I trial was unable to provide evidence that postoperative TAIC administration has a beneficial effect.