Cardiac Transplantation across Preformed HLA-Antibody Barriers: Results of a Peritransplant Desensitization Protocol

Abstract

Purpose A growing number of patients awaiting heart transplantation presents with preformed anti-HLA antibodies. This allosensitization prolongs waiting times and increases morbidity and mortality. In 2017, we designed aprotocol for peritransplant desensitization of heart-transplanted patients showing preformed anti-HLA donor specific antibodies (pfDSA), i.e. a positive virtual crossmatch. The protocol included: an intraoperative single dose of the IL-6 receptor antibody Tocilizumab (10mg/kg) just before releasing the aortic clamp; 5 sessions of plasmapheresis (PE, 1 before transplantation, 1 during transplantation and 3 thereafter); an infusion (2g/kg) of IgA and IgM-enriched human immunoglobulins G (IgGAM) after the last PE; and a single Rituximab dose (375mg/m2) after IgGAM. IgGAM are repeated every 4 weeks (0.5g/kg) for a maximum of 6 months, if DSA are still positive. Aim of this study was to present the preliminary results of this peritransplant desensitization protocol. Methods Records of heart-transplanted patients at our institution between 01/2017 and 10/2018 were reviewed. Patients with pfDSA (positive virtual crossmatch) formed the case group, remaining patients the control group. Median (IQR) follow-up amounted to 9 (5, 16) months. Results During the study period, among the 42 transplanted patients, 9 (21%) patients formed the case group and the remaining 33 (79%) the control group. All 9 case patients showed pfDSA with >50% pre-transplant panel reactive antibodies (PRA). Pretransplant recipient and donor characteristics did not differ between groups. Post-transplant, no case patients showed severe primary graft dysfunction, but 6 (19%) control patients did (p=0.19). At treatment end, pfDSA were cleared in 4 (44%) patients. At 1-year follow-up, survival was 100% vs. 75% in case and control patients (p=0.18); freedom from biopsy-confirmed rejection (Grade >1R) was 89% vs. 92% in case (n=1) and control (n=2) patients (p=0.78); and from steroid-pulsed therapy 89% vs. 82% in case (n=1) and control (n=5) patients (p=0.76), respectively. One case patient showed minimal AMR (pAMR 1+). Conclusion The present study showed that heart transplantation across positive crossmatch barriers can be feasible and safe. The present peritransplant desensitization protocol yielded good survival and rejection-free survival.