31 Value of Immunoperoxidase Staining of C3d in the Diagnosis of Antibody Mediated Rejection in Heart Transplant Recipients

Purpose: According to a recent consensus conference on antibody-mediated rejection (AMR), AMR should be defined solely by pathologic criteria. The presence of donor specific antibody (DSA) was not mandated in the AMR definition as DSA were not always detected during AMR episodes. This may be due to DSA being adhered to the donor heart. It is believed that the detection of DSA during AMR episodes might lead to worse outcome. We reviewed our heart transplant patients with AMR to assess this hypothesis. Methods and Materials: We evaluated 53 patients status post heart transplant from 2003 to 2010 with treated AMR within the first year post transplant. Of these, 14 patients had concomitant circulating DSA and 39 patients did not. Outcomes were compared for subsequent 3-year survival, freedom from cardiac allograft vasculopathy (CAV, stenosis 30%), and freedom from non-fatal major adverse cardiac events (NF-MACE: myocardial infarction, heart failure, coronary stenting, need for defibrillator, stroke, and new peripheral vascular disease). Results: Patients who developed treated AMR with and without circulating DSA were found to have similar subsequent 3-year survival (71% vs. 82%, p 0.37), subsequent 3-year freedom from CAV (80% vs. 86%, p 0.62), and freedom from NF-MACE (100% vs. 92%, p 0.29). There was no difference in the incidence of hemodynamic compromise rejection between groups (7% vs. 8%, p 0.96). Conclusions: The finding of DSA in conjunction with pathology confirmed AMR does not appear to impact 3-year outcome after heart transplantation. Further studies to assess strength and other characteristics of DSA during AMR episodes may shed light to define its role in clinical AMR.