C. Wimmer

Impact of cyclosporine versus tacrolimus on the incidence of de novo malignancy following liver transplantation: a single center experience with 609 patients.

De novo malignancies are a major cause of late death after liver transplantation. Aim of the present study was to determine whether use of cyclosporine versus tacrolimus affects long‐term tumor incidence considering potential confounders. De novo malignancies in 609 liver transplant recipients at Munich Transplant Centre between 1985 and 2007 were registered. In 1996, the standard immunosuppressive regimen was changed from cyclosporine to tacrolimus. Different effects of those drugs on long‐term tumor incidence were analyzed in multivariate analysis. During 3765 patient years of follow‐up (median 4.78 years), 87 de novo malignancies occurred in 71 patients (mean age 47.5 ± 13.3 years, mean time after liver transplantation 5.7 ± 3.7 years). The cumulative incidence of de novo malignancies was 34.7% for all tumor entities after 15 years as compared to 8.9% for a nontransplanted population. The most frequent tumors observed were nonmelanoma skin cancers (44.83%). Moreover, post‐transplant lymphoid disease, oropharyngeal cancer (n = 6, 6.9%), upper gastrointestinal tract cancer (n = 4, 4.6%), lung cancer (n = 4, 4.6%), gynecological malignancies (n = 4, 4.6%), and kidney cancer (n = 3, 3.45%) were detected. Multivariate analysis revealed recipient age [hazards ratio (HR) 1.06], male gender (HR 1.73), and tacrolimus‐based immunosuppression (HR 2.06) as significant risk factors. Based on those results, a tacrolimus‐based immunosuppression should be discussed especially in older male patients. Whether reducing tacrolimus target levels may reduce the risk for de novo malignancies has yet to be determined in prospective trials.

Single-shot antithrombin in human pancreas-kidney transplantation: reduction of reperfusion pancreatitis and prevention of graft thrombosis.

Reperfusion pancreatitis and graft thrombosis often induce early graft loss in simultaneous pancreas–kidney (SPK) transplantation. Antithrombin (AT) is a coagulatory inhibitor with pleiotropic activities that reduces experimental ischemia/reperfusion injury. This study retrospectively analyses prophylactic high‐dose AT application in patients with first SPK. In an university transplantation center, 53 consecutive patients with SPK were studied without randomization. In one group, 3000 IU of AT was given intravenously before pancreatic reperfusion (AT, n = 24). Patients receiving standard therapy including postoperative AT supplementation (controls, n = 29) served as controls. Daily blood sampling was performed as a part of the clinical routine during four postoperative days. There were no differences in demographic and laboratory parameters [donor/recipient age, ischemia time, perfusion solution, body weight, mismatches] between both groups. Baseline creatinine values were lower in the control group versus AT group (P < 0.05). Coagulatory parameters and bleeding incidence were not influenced by AT, while incidence of graft thrombosis was reduced (control: 7/29; AT: 4/24; relative reduction of risk: −33%; P < 0.05). Single‐shot AT application during SPK modulated serum lipase activity on postoperative days 2 and 3, and minimized risk for graft thromboses without increasing perioperative bleeding. This new concept should deserve testing in a prospective clinical trial.

A calcineurin antagonist-free induction/maintenance strategy for immunosuppression in elderly recipients of renal allografts from elderly cadaver donors: long-term results from a prospective single centre trial.

Abstract:  Background:  With the aim to improve the inferior outcomes in elderly recipients of kidneys from elderly cadaver donors, we applied and investigated a therapeutic regimen consisting of calcineurin inhibitor (CNI)‐free, mycophenolate mofetil (MMF)‐based immunosuppressive (i.s.) induction/maintenance protocol. In this article, we report the long‐term results of this clinical trial.

IG-therasorb immunoapheresis in orthotopic xenotransplantation of baboons with landrace pig hearts.

BACKGROUND The major problem of xenotransplantation is, that hyperacute xenograft rejection (HXR) causes graft failure within minutes or a few hours because of natural antibodies and activation of the complement system. As a preclinical model we transplanted pig hearts orthotopically into baboons. To prevent HXR after orthotopic xenotransplantation (oXHTx), the immunoglobulins (Ig) and natural antibodies were adsorbed to reusable Ig-Therasorb immunoadsorption (IA) columns. METHODS We performed three oXHTx of landrace pig hearts into baboons (19+/-6.8 kg), using extracorporeal circulation (ECC) connected to the IA unit. After separating the recipients blood into plasma and cellular fraction by a plasma filter, plasma flow was directed to the Ig-Therasorb column coated with polyclonal sheep-antibodies against human IgG, IgM, and IgA. Intraoperative treatment consisted of 4 cycles of IA. For a control, we transplanted one pig heart into a baboon (16.9 kg) without applying IA. Perioperatively, serum concentrations of Ig, anti-pig-antibodies, complement and cardiac enzymes were determined. Tissue samples of myocardium were collected at the end of the study for immunohistochemical examinations, light microscopic examination (LM) and electron microscopic examination (EM). For cardiac monitoring after oXHTx, we used ECG, echocardiography, and invasive measurement of cardiac output. To prevent a mismatch of donor and recipient heart size, the donor pig had a 30-40% lower body weight than the recipient baboon. RESULTS Four cycles of IA removed >80% of IgG, IgM, and IgA from plasma. The graft of the control animal failed after 29 min. The first oXHTx with IA was intentionally terminated after 100 min, the second oXHTx after 11 hr and the third oXHTx after 21 hr. All xenografts showed no histological signs of HXR. After weaning off ECC, these donor hearts worked in sinus rhythm without electrocardiographic ST-segment elevation. An excellent cardiac output was measured by echocardiography and thermodilution (2 L/min). Serological parameters indicating cardiac damage were significantly lower after IA if compared with the control experiment. Macroscopically, the xenograft of the control animal showed massive hemorrhage in comparison with the almost inconspicuous grafts after IA. The myocardium of the IA group demonstrated fewer deposits of Ig and complement components compared with the control animal. CONCLUSION Baboons do not hyperacutely reject a porcine xenograft after antibody depletion by the Ig-Therasorb column. In our experiment only 4 cycles of immunoapheresis effectively prevented HXR after oXHTx of baboons. The Ig-Therasorb column is a reusable device, which can be handled easily in combination with the ECC. IA must be tested in oXHTx longterm survival experiments, especially in combination with transgenic pig organs, which could be a reliable preclinical approach for future clinical xenotransplantation.

Calcineurin‐inhibitor avoidance in elderly renal allograft recipients using ATG and basiliximab combined with mycophenolate mofetil

In old recipients of renal allografts from old donors, benefits of calcineurin‐inhibitors (CNI) are curtailed by nephrotoxicity. Intending to improve the outcome of these recipients, we analyzed a CNI‐free immunosuppressive regimen consisting of anti‐thymocyte globulin (ATG), basiliximab, mycophenolate mofetil (MMF) and steroids. Kidney allograft recipients with low immunological risk (panel reactive antibodies <30%) were eligible for this study. Immunosuppression induction included ATG (4 mg/kg, day 0), basiliximab (20 mg, day 0 + 4) and steroids, followed by MMF (TL 2–6 μg/ml) and steroid maintenance treatment. Patient and graft survival rates respectively were 89.3% and 85.4% (12 months), and 86.6% and 76.8% (24 months). Delayed graft function occurred in 44.6%. S‐creatinine at 12 months was 1.85 ± 0.94 mg/dl. Thirty patients (53.6%) showed biopsy‐proven rejections (6x Banff 3, 13x Banff 4I and 16x Banff 4II), 77% of which were steroid‐sensitive, 23% required antibody treatment. After 12 months, 83% of the patients had an MMF‐based immunosuppression, 43% were CNI‐free. Cytomegalovirus (CMV) infections occurred in 28, tissue‐invasive disease in three patients. Despite acceptable renal graft survival and function in some of patients with marginal organs, high incidences of rejections and CMV infections suggest the feasibility of CNI‐avoidance using an MMF‐based protocol only in carefully selected patients.

Prevention of hyperacute xenograft rejection in orthotopic xenotransplantation of pig hearts into baboons using immunoadsorption of antibodies and complement factors

Abstract To prevent hyperacute xenograft rejection (HXR) caused by preformed natural antibodies (XNAb) after orthotopic heart xenotransplantation (oXHTx) of landrace pig hearts into baboons, we used immunoadsorption of immunoglobulins IgG, IgM and IgA and complement with the reusable Ig‐Therasorb column. In addition to functional data, tissue was sampled for histological, immunohistochemical and electron microscopical analysis. We performed three oXHTx of landrace pig hearts to baboons using extracorporeal circulation (ECC) connected to the immunoadsorption unit. Intraoperative treatment consisted of four cycles of immunoabsorption (IA). One oXHTx of a baboon without IA served as a control. A mismatch of donor and recipient heart size was prevented by selecting a 30‐40% lower body weight of donor pigs than recipients. Four cycles of IA removed more than 80% of IgG, IgM and IgA, 86% of anti‐pig antibodies and 66% of complement factors C3 and C4 from plasma. The graft of the control animal failed after 29 min. Orthotopic xenotransplantation with IA was selectively terminated after 100 min, 11 h and 21 h, respectively without any histological signs of HXR in light and electron microscopy. After weaning off from ECC these donor xenografts showed sufficient function with normal ECG and excellent cardiac output in echocardiography and invasive measurement (1.93 ± 0.035 l/min). The myocardium of the control xenograft demonstrated more deposits of Ig and complement components (C3, C4) than in the IA group. Baboons survive HXR after orthotopic pig heart xenotransplantation due to antibody depletion by reusable Ig‐Therasorb column treatment. Long‐term survival in an orthotopic baboon xenotransplantation model after IA, especially in combination with transgenic pig organs, could be a reliable preclinical trial for future clinical xenotransplantation programs.

Combined Lung and Liver Transplantation With Extracorporeal Membrane Oxygenation Instead of Cardiopulmonary Bypass

From the *Department of Anesthesiology, ‡Department of Heart Surgery, ¶Department of General, Visceral, Transplant, Vascular and Thoracic surgery, #Department of Internal Medicine V (Pneumology), **Transplantation Center Munich, †Munich Lung Transplant Group, University Hospital, Ludwig-Maximilians-University Munich, Germany; and §German Center for Lung Research. Address reprint requests to Vera von Dossow, MD, Department of Anesthesiology, University Hospital, Ludwig-Maximilians-University Munich, Marchioninistr. 15, D-81377 Munich, Germany. E-mail: vera.dossow@med.uni-muenchen.de

COMBINATION OF HDAF-TRANSGENIC PIG HEARTS AND IMMUNOADSORPTION IN HETEROTOPIC XENOTRANSPLANTATION OF IMMUNOSUPPRESSED BABOONS

INTRODUCTION Hyperacute xenograft rejection (HXR) and acute vascular rejection (AVR) after xenotransplantation are triggered by xenoreactive antibodies (XAb) and an activated complement cascade. In a heterotopic (abdominal) xenotransplantation model we combined immunoadsorption (IA, Ig-Therasorb column) and a quadruple immunosuppressive drug therapy in recipient baboons with donor pig hearts transgenic for human decay accelerating factor (hDAF). METHODS According to XAb titers between 6 and 14 cycles of IA were performed preoperatively in 4 recipient baboons (18.6 +/- 2.5 kg). Hearts of hDAF-transgenic donor pigs (6.1 +/- 1.1 kg, Imutran Ltd., a Novartis Pharma AG Company, Basel, Switzerland) were heterotopically transplanted using the abdominal technique in baboons. Immunosuppression consisted of cyclophosphamide (CyP) induction therapy, ERL080 (Novartis Pharma AG), cyclosporin A (CyA, Neoral), and steroids. Blood levels of mycophenolate, CyA, immunoglobulins (Ig), anti-pig-antibodies, complement factors, and cardiac enzymes were determined. Abdominal electrocardiography (ECG), echocardiography, and palpation were used for monitoring of the pig hearts. Myocardial tissue specimens were examined using immunohistochemistry, light microscope (LM), and electron microscope (EM). RESULTS Ten cycles of IA alone removed 78% of XAb and accordingly IgM, IgG, IgA, complement C3, and C4. None of the xenografts was hyperacutely rejected, but xenograft failure occurred after 5.0 +/- 1.3 days (range, 2.4-8.0 days) because of an AVR associated with a rapid XAb increase within 24 hours. White blood cell count (10.3 +/- 2.2 G/L) showed a maximum of 13.1 +/- 2.1 (day 1) and constant levels (1.4 +/- 0.3-2.1 +/- 1.3 G/L) between day 3 and 6. Histology (LM/EM) showed massive hemorrhage, necrosis, and vascular thrombi as signs of AVR. CONCLUSION Although HXR was prevented by using IA and hDAF-transgenic donor hearts, AVR was not avoided due to insufficient immunosuppressive regimen used and a missed postoperative IA treatment as a result of an inefficient control of XAb production.