Donor Specific Antibodies after Heart Transplantation: Can They Be Treated?

PURPOSE The development of post-transplant donor specific antibody (DSA), especially those that bind complement (C1q+), has been associated with development of cardiac allograft vasculopathy (CAV). Our strategy is to employ densitization for patients with DSA and cardiac dysfunction and/or C1q+. The purpose of this study was to assess the response of C1q+ DSA to desensitization therapy. METHODS We reviewed 43 heart transplant pts between 2010 and 2018 who developed DSA and received post-transplant desensitization with IVIG/rituximab and/or plasmapheresis/bortezomib. There were 25 pts with C1q+ DSA and 18 pts with cardiac dysfunction and DSA; 20 had C1q DSA and cardiac dysfunction. Reponse was defined by antibody binding of the immunodominant DSA (highest mean fluorescence intensity (MFI)) by Luminex neat assay 6 months post therapy. Response was compared between pts with C1q+ vs C1q- DSA and pts with and without cardiac dysfunction. The effect of desensitization cardiac function was also assessed. RESULTS Pts with C1q+ DSA appear to have a similar response to desensitization therapy in terms of decreased immunodominant MFI after therapy compared to C1q- DSA. DSA with and without cardiac dysfunction also appear to have similar response to therapy. In pts with DSA with cardiac dysfunction, 75.0% (15/20 pts) had improved cardiac function following therapy. CONCLUSION A majority of transplant pts with DSA with/without C1q+ or with/without cardiac dysfunction did respond to desensitization therapy, however it is not clear whether this treatment would lead to a decrease in CAV. Long term follow up and larger number of pts will be needed to answer this question.