Donor specific antibodies before and after kidney transplant: the University of Colorado Experience

We summarize in this manuscript our donor specific antibody (DSA) screening experience in the past six years as it applies to pre-existing DSA, de novo DSA, and post-transplant DSA treatment. Of 547 patients receiving a kidney or kidney/pancreas with negative pre-transplant flow cytometry crossmatch (FCXM), 196 had DSA (mean fluorescence intensity, MFI >or= 500) detected prior to transplant by single antigen bead analysis. Acute rejection rates at one year were similar in DSA+ versus DSA- (15% versus 12%, respectively, p=0.22), although acute rejection occurred earlier in the DSA+ group. De novo DSA was detected in 65 of 261 patients (27%). All DSA was detected within the first posttransplant year. While acute rejection was more likely in patients with de novo DSA (29% versus 9.5% in those with no DSA), prospective DSA screening failed to predict this outcome as DSA was detected at the time of or after a rejection episode in 16 of 19 patients with both DSA and acute rejection. Two-year estimated graft survival was significantly worse in patients with versus without DSA, but was identical when removing patients with a prior acute rejection episode from the analysis. We have used a protocol of high dose (5 gm/kg) intravenous immunoglobulin infused over the course of 6 months in patients with DSA and either chronic graft dysfunction or following a recent acute antibody mediated rejection (AMR) episode. DSA MFI was reduced by 18% from the time of initiation to last follow up. This effect was largely due to reductions in class I DSA (-37%) and DSA in patients with a recent acute AMR (-51.5%), with a minimal effect on class II DSA and DSA in patients with chronic graft dysfunction. Despite treatment directed at antibody-producing plasma cells, antibody levels either persisted or worsened with no improvement in graft function. Overall, DSA is more amendable to treatment when associated with a recent acute rejection event.