SUCCESSFUL ABO INCOMPATIBLE PEDIATRIC LIVER TRANSPLANTATION UTILIZING SELECTIVE PLASMAPHERESIS

Abstract

O160 Aims: It has been reported that ABO incompatible grafts during liver transplantation results in lower patient and graft survival. Also it is believed that ABO incompatible liver grafts will have an increase in incidence and severity of acute cellular rejection. The aim of this study is to report our experience of emergent transplantation of pediatric recipients utilizing ABO incompatible, mismatched grafts while using selective plasmapheresis with an induction protocol using daclizumab with tacrolimus, mycophenolate and steroids. Methods: From July 1998 to November 2003, 115 liver transplants in 101 pediatric recipients were prospectively followed for outcomes of which 11 (10.8%) of the children received an ABO incompatible liver allograft emergently. ABO incompatible liver allograft (n=11) consisted of group pairings which included blood type B donors to type A liver recipient (B to A, n = 4), A to B (n = 2), A to O (n=4), and AB to A (n =1). All patients received similar immunosuppression with induction therapy of daclizumab. Additional intravenous methylprednisolone (10-20 mg/kg per dose) was administered when evidence of hemolysis was confirmed by increased AB antibody titers on serial isohemagglutinins assay, evidence of hemolysis was suggested by increased indirect bilirubin, hematuria, or increased haptoglobin. If the titers did not respond to methylprednisolone, plasmapheresis was instituted plasmapheresis. Total plasma exchange and splenectomy were not used for pre-transplant or post-transplant as induction treatment. Results: Two of eleven (18%) children with ABO incompatible allografts had three rejection episodes compared with 48/91 (53%) children with 111 rejection episodes in ABO compatible allograft placement. The incompatible liver group was similar in age (8.1 ± 6.2 years vs. 6.5 ± 6.2 years; p = NS), time to first rejection (135 ± 178 days vs. 340 ± 396 days; p = NS), with the compatible group having longer mean follow-up (573 ± 372 days vs. 930 ± 568 days, p = 0.013). Only one patient received plasmapheresis that demonstrated anti-B titers of 1:32 or less at baseline and increased to 1:1024 with hemolysis, an increase in serum total bilirubin to 8.4 mg/dl from 3.7mg/dl and hematuria on POD #6 with unresponsive steroid therapy. Plasmapheresis was instituted for 10 days, 80% total blood replacement for three days and 150% replacement for 7 days. There were no post-operative complications of hepatic arterial or portal venous thrombosis, or vena caval occlusion in the ABO incompatible group. One child lost their allograft following a percutaneous transhepatic cholangiogram due to a intra-hepatic hematoma. Patient actuarial survival for ABO matched children vs ABO incompatible children was 84/90(93.3%), versus 11/11 (100%) and graft survival was 84/101 (89.7%) vs 10/11 (91%) at one year. Conclusions: ABO mismatched grafts can be used without an increase in patient/graft mortality or an increase in rejections when an enhanced immunosuppressive protocol of daclizumab/tacrolimus/mycophenolate/prednisone is used. Plasmapheresis may be reserved for times of increased anti-ABO titers with clinical hemolysis for graft salvage.