O.O.Adebiyi, J.Gralla, P.Klem, B.Freed, S.Davis, A.C.Wiseman and J.E.Cooper
The widespread utilization of single-antigen bead (SAB) assays prior to kidney transplantation has improved the detection of donor-specific antibody (DSA) in potential transplant recipients. Many studies have documented inferior renal graft outcomes in the presence of pretransplant DSA (1–15). However, the clinical importance of such DSA in the setting of a negative flow cytometry crossmatch (FCXM) at transplant remains controversial and the need for desensitization uncertain. There are limited published data regarding the impact of specific DSA characteristics such as class, strength or whether DSA persisted posttransplant on renal allograft outcomes when flow cytometry is negative. Additionally, the clinical significance of waxing/waning HLA antibodies pretransplant that are donor specific has not been reported in detail.
The use of desensitizing agents prior to transplant for those patients at increased immunologic risk based on pretransplant screening has permitted successful transplantation for those who may not otherwise have had access to this treatment, despite higher acute rejection rates and inferior graft survival compared to those without preformed DSA (16,17). Clinical experience has shown these treatments to be necessary for patients with high-risk immunologic screening assays (complement-dependent cytotoxicity crossmatch [CDC] and/or FCXM positivity); however, the necessity of these costly therapies in the setting of SAB positivity alone remains uncertain, with practices varying center by center (17,18).
Since September 2007, all renal transplant recipients at our center have undergone immunologic screening with both SAB and FCXM assays prior to transplantation. The aim of this study was to evaluate the impact of pretransplant DSA in the setting of negative FCXM screening on intermediate-term renal allograft outcomes in patients not receiving desensitization therapy. To our knowledge,this is the largest study of outcomes following kidney transplantation in the setting of low-level pretransplant DSA with negative FCXM to date.