P042 : PREVALENCE AND CLINICAL SIGNIFICANCE OF C1q BINDING DONOR SPECIFIC ANTIBODIES IN RENAL TRANSPLANTATION

Abstract

Antibody-mediated injury is a major cause of renal allograft dysfunction and loss. In this study, we aimed to determine the prevalence and clinical significance of complement binding donor-specific antibodies (C1q + DSA) in renal transplant recipients with functioning allografts after 3–30 years post-transplantation. A total of 405 patients who received renal transplantation at our center from 1982 to 2009 were enrolled in this study. HLA-A, B, C, DR and DQ typing information was available for all patient and donor pairs. All patients were transplanted based on a negative crossmatch and had current serum samples available for DSA testing. Serum IgG- and C1q-binding HLA antibodies were tested using the Single Antigen Bead assay. Based on DSA status, 3 distinct groups were identified in our patient population: 33 patients (8%) with C1q + DSA, 44 patients (11%) with C1q- DSA and 328 patients (81%) without DSA. There were no differences between the groups in terms of gender, race, previous transplantation and induction therapy. However, age and transplant type were significantly different between the groups, with C1q + DSA + patients receiving transplantation at a younger age and more frequently from deceased donors than the other groups ( p p Conclusion Our results indicate that C1q + DSA occured at a frequency of 8% in patients with functioning renal allografts 3–30 years after transplantation. Such antibodies occured more frequently in younger patients and those who received deceased donor allografts. C1q + DSA were associated with an increased incidence of acute and chronic antibody mediated rejection. Thus, monitoring of high-strength/complement binding DSA may assist in the identification of patients at risk for graft loss late after transplantation.