The impact of C4d-negative acute antibody-mediated rejection on short-term prognosis among kidney transplant recipients.

Aim: We aimed to investigate the clinical and pathological features of C4d-negative acute antibody-mediated rejection (aAMR), and examined the impact of C4d-negative aAMR on short-term prognosis.

Methods: From 2005 to 2011, 626 kidney transplantations were performed in our institution and related hospitals. We excluded 174 ABO-incompatible transplantations, and analysed clinical and pathological data from the remaining 452 until December 2013.

Results: During the follow-up period, 39 patients underwent aAMR. We divided them into two groups. According to C4d positivity in each patient's first AMR, we divided the cohort into a C4d-positive aAMR group and a C4d-negative aAMR group, using the new Banff 2013 classification. We compared each aAMR patient's features to controls. Clinical and pathological characteristics were similar in both groups and the short-term outcomes of the two groups were similar, but both were worse than control.

Conclusion: C4d-negative aAMR resembles C4d-positive aAMR in terms of clinical and pathological features, and that C4d positivity has no influence on short-term outcome.