P1739immunosuppression With Calcineurin Inhibitor After Renal Transplant Failure Prevents Allosensitization

Abstract

Background and Aims Retransplantation is an important option to consider in patients who return to dialysis after graft failure since it reduces mortality. HLA allosensitization hinders retransplantation, and immunosuppression withdrawal after graft failure seems to favor sensitization. There are no established protocols on the immunosuppressive treatment that should be maintained after transplant failure in order to reduce the development of anti-HLA antibodies. The aim of the study is to evaluate the effect of immunosuppression withdrawal on the development of anti-HLA antibodies after graft loss. Method A retrospective analysis including 77 patients who lost their first renal graft between 1/1/2006-12/31/2015 was performed. 22 patients with preemptive second kidney transplant were included. Maintenance immunosuppression was collected in months 1, 3 and 6 after graft failure. Patients were divided into two groups according to the presence or not of calcineurin inhibitor (CNI) as maintenance treatment. Two sera were analyzed per patient, one immediately prior to graft loss and another one after graft failure (Luminex®, Single Antigen). In patients in whom transplantectomy was performed, the selected serum after transplant failure was already after graft nephrectomy. PRA was calculated (cPRA) in each serum and the development of de novo donor-specific antibodies (dnDSA) was evaluated. Results Selected sera were extracted 1.0 month before graft failure (interquartile range 0.3-2.0) and 7.6 months after transplant failure (interquartile range 6.0-12.2). By multivariate logistic regression analysis, graft nephrectomy was an independent risk factor for cPRA>75% after transplant failure (OR 4.9, CI 95% 1.0-22.2, p=0.038). Similarly, the absence of CNI at 6 months after graft failure was significantly related to cPRA>75% in the multivariate analysis (OR 4.8, CI 95% 1.5-15.0, p=0.006). It was possible to analyze dnDSA formation in 73 patients. The absence of CNI at 6 months after graft loss was an independent risk factor for dnDSA development (OR 23.2, CI 95% 5.3-100.6, p <0.001). There were no differences in the management of other immunosuppressive drugs. Conclusion The absence of maintenance treatment with CNI at the sixth month after graft loss is a risk factor for sensitization. Therefore, immunosuppressive maintenance treatment based on CNI after transplant failure should be considered, since it seems to prevent HLA allosensitization.