The aim of our study was to evaluate the relevance of complement-binding donor-specific antibodies (DSA) for prediction of antibody-mediated rejection after liver transplantation. Sera from 123 liver transplant recipients were retrospectively defined for HLA specificity and complement-fixing activity using the single antigen beads, C1q and C3d techniques. Liver-recipients´ sera were tested before transplantation, 3, 6 months and one year after transplantation. Patients were followed up for graft survival and rejection incidence for one year after transplantation. All patients with pre-transplant complement-binding DSA developed severe antibody-mediated rejection after transplantation, while three recipients out of four, who produced de novo complement-fixing DSA, developed AMR. Definition of DSA with respect to complement-fixing activity may provide clinically relevant information about the risk of antibody-mediated rejection after liver transplantation This article is protected by copyright. All rights reserved.

The B-cell activating factor (BAFF) cytokine has important functions for the survival and maturation of B lymphocytes, which implies that this cytokine might play a role in the development of antibody-mediated rejection (AMR) after kidney transplantation. In our study, we compared the concentrations of the soluble BAFF cytokine in kidney graft recipients with AMR and patients without rejection with the goal of testing the hypothesis whether BAFF level measurement might be useful as a diagnostic marker of AMR. The study included a cohort of 19 high-risk patients with diagnosed AMR and 17 control patients free of rejection. BAFF was measured in all patients before transplantation, during the rejection episodes, and three months after transplantation in patients free of rejection using the Luminex technique. Before transplantation, the serum concentrations of BAFF in patients with AMR and kidney recipients without rejection did not significantly differ. After transplantation, however, BAFF levels were significantly lower in patients with AMR and also in patients with concurrent humoral and cellular rejection compared with patients without rejection (p < 0.05 and p < 0.01, respectively). No correlation was found between BAFF and the production of donor-specific antibodies (DSA) before and after transplantation. Patients experiencing AMR and simultaneous cellular and AMR had significantly lower concentrations of BAFF in comparison with patients free of rejection.