A. Zeevi

Baboon-to-human liver transplantation

Our ability to control both the cellular and humoral components of xenograft rejection in laboratory experiments, together with an organ shortage that has placed limits on clinical transplantation services, prompted us to undertake a liver transplantation from a baboon to a 35-year-old man with B virus-associated chronic active hepatitis and human immunodeficiency virus infection. Liver replacement was performed according to conventional surgical techniques. Immunosuppression was with the FK 506-prednisone-prostaglandin regimen used routinely for hepatic allotransplantation, to which a daily non-myelotoxic dose of cyclophosphamide was added. During 70 days of survival, there was little evidence of hepatic rejection by biochemical monitoring or histopathological examination. Products of hepatic synthesis, including clotting factors, became those of the baboon liver with no obvious adverse effects. Death followed a cerebral and subarachnoid haemorrhage that was caused by an angioinvasive aspergillus infection. However, the underlying cause of death was widespread biliary sludge that formed in the biliary tree despite a seemingly satisfactory choledochojejunostomy. During life and in necropsy samples, there was evidence of the chimerism that we believe is integral to the acceptance of both xenografts and allografts. Our experience has shown the feasibility of controlling the rejection of the baboon liver xenograft in a human recipient. The biliary stasis that was the beginning of lethal infectious complications may be correctable by modifications of surgical technique. In further trials, the error of over-immunosuppression should be avoidable.

Cytomegalovirus serologic status and postoperative infection correlated with risk of developing chronic rejection after pulmonary transplantation.

Twenty-seven patients received pulmonary transplants during the period since we began routine use of cytomegalovirus-seronegative blood products for CMV-seronegative recipients. Preoperative serologic status of the recipient and the occurrence of cytomegalovirus infection in the postoperative period were correlated with development of obliterative bronchiolitis (OB) as diagnosed by transbronchial biopsy (TBB). Patients included 20 heart-lung and 7 double-lung recipients. OB occurred in 18 of 27 patients. All 3 CMV seronegative recipients receiving lungs from a seropositive donor and 9 of 10 CMV recipients seropositive at the time of transplantation developed OB compared with only 6 of 14 CMV seronegative patients receiving seronegative grafts (P = 0.018). CMV infection occurred in 10/27 patients, of whom 5 were asymptomatic; 90% of these patients developed OB. Donor-specific alloreactivity, based on primed lymphocyte testing (PLT) of bronchoalveolar lavage cells was found at the time of diagnosis of OB in 23 of 27 patients. A positive PLT was significantly associated with the presence of OB (P = 0.017). We conclude that preoperative seropositive status for CMV, grafting of organs from seropositive donors, and postoperative CMV infection are significant risk factors for developing OB. That OB is, in part, an immunologically mediated form of injury and represents chronic rejection is supported by the presence of donor-specific alloreactivity in BAL lymphocytes from all recipients with OB.

Voriconazole Prophylaxis in Lung Transplant Recipients

Lung transplant recipients have one of the highest rates of invasive aspergillosis (IA) in solid organ transplantation. We used a single center, nonrandomized, retrospective, sequential study design to evaluate fungal infection rates in lung transplant recipients who were managed with either universal prophylaxis with voriconazole (n = 65) or targeted prophylaxis (n = 30) with itraconazole ± inhaled amphotericin in patients at high risk (pre‐ or posttransplant Aspergillus colonization [except Aspergillus niger]). The rate of IA at 1 year was better in lung transplant recipients receiving voriconazole prophylaxis as compared to the cohort managed with targeted prophylaxis (1.5% vs. 23%; p = 0.001). Twenty‐nine percent of cases in the targeted prophylaxis group were in patients colonized with A. niger who did not receive itraconazole. A threefold or higher increase in liver enzymes was noted in 37–60% of patients receiving voriconazole prophylaxis as compared to 15–41% of patients in the targeted prophylaxis cohort. Fourteen percent in the voriconazole group as compared to 8% in the targeted prophylaxis group had to discontinue antifungal medications due to side effects. Voriconazole prophylaxis can be used in preventing IA in lung transplant recipients. Regular monitoring of liver enzymes and serum concentrations of calcineurin inhibitors are required to avoid hepatotoxicity and nephrotoxicity.

The Banff 2015 Kidney Meeting Report: Current Challenges in Rejection Classification and Prospects for Adopting Molecular Pathology

The XIII Banff meeting, held in conjunction the Canadian Society of Transplantation in Vancouver, Canada, reviewed the clinical impact of updates of C4d‐negative antibody‐mediated rejection (ABMR) from the 2013 meeting, reports from active Banff Working Groups, the relationships of donor‐specific antibody tests (anti‐HLA and non‐HLA) with transplant histopathology, and questions of molecular transplant diagnostics. The use of transcriptome gene sets, their resultant diagnostic classifiers, or common key genes to supplement the diagnosis and classification of rejection requires further consensus agreement and validation in biopsies. Newly introduced concepts include the i‐IFTA score, comprising inflammation within areas of fibrosis and atrophy and acceptance of transplant arteriolopathy within the descriptions of chronic active T cell–mediated rejection (TCMR) or chronic ABMR. The pattern of mixed TCMR and ABMR was increasingly recognized. This report also includes improved definitions of TCMR and ABMR in pancreas transplants with specification of vascular lesions and prospects for defining a vascularized composite allograft rejection classification. The goal of the Banff process is ongoing integration of advances in histologic, serologic, and molecular diagnostic techniques to produce a consensus‐based reporting system that offers precise composite scores, accurate routine diagnostics, and applicability to next‐generation clinical trials.

Autologous lymphokine-activated killer cell therapy of Epstein-Barr virus-positive and -negative lymphoproliferative disorders arising in organ transplant recipients

Lymphoreticular malignancies, collectively called posttransplant lymphoproliferative disorders (PTLD), eventually develop in 2-5% of organ transplant recipients. They frequently undergo regression when immunosuppression is reduced or stopped. This feature has been associated with a previous or de novo Epstein-Barr virus (EBV) infection. We herein describe immunotherapy with autologous lymphokine-activated killer (LAK) cells in seven patients with PTLD (four EBV-positive patients and three EBV-negative patients). Autologous peripheral blood mononuclear cells were obtained by leukapheresis, depleted of monocytes, and cultured in the presence of interleukin 2 for 10 to 11 days. A single dose of 5.2 x 10(9) to 5.6 x 10(10) LAK cells was given intravenously. Systemic interleukin 2 was not administered. The four patients with EBV+ PTLD had complete tumor regression; two of them developed controllable rejection. Three patients are well 13-16 months after treatment; the fourth patient died of pneumonia 41 days after infusion. Three patients with EBV- lymphomas had no response despite prior evidence that their tumors also were subject to immune surveillance. Two of these three patients died after being given other treatment, and the third patient has persistent tumor. In conclusion, autologous LAK cell infusion was effective for treatment of four EBV+ organ transplant recipients. LAK cell efficacy for three patients with EBV- PTLD was not evaluable under the management circumstances in which this treatment was utilized.

Preformed and de novo donor specific antibodies in visceral transplantation: long-term outcome with special reference to the liver.

Despite improvement in early outcome, rejection particularly chronic allograft enteropathy continues to be a major barrier to long‐term visceral engraftment. The potential role of donor specific antibodies (DSA) was examined in 194 primary adult recipients. All underwent complement‐dependent lymphocytotoxic crossmatch (CDC‐XM) with pre‐ and posttransplant solid phase HLA–DSA assay in 156 (80%). Grafts were ABO‐identical with random HLA‐match. Liver was included in 71 (37%) allografts. Immunosuppression was tacrolimus‐based with antilymphocyte recipient pretreatment in 150 (77%). CDC‐XM was positive in 55 (28%). HLA–DSA was detectable before transplant in 49 (31%) recipients with 19 continuing to have circulating antibodies. Another 19 (18%) developed de novo DSA. Ninety percent of patients with preformed DSA harbored HLA Class‐I whereas 74% of recipients with de novo antibodies had Class‐II. Gender, age, ABO blood‐type, cold ischemia, splenectomy and allograft type were significant DSA predictors. Preformed DSA significantly (p < 0.05) increased risk of acute rejection. Persistent and de novo HLA–DSA significantly (p < 0.001) increased risk of chronic rejection and associated graft loss. Inclusion of the liver was a significant predictor of better outcome (p = 0.004, HR = 0.347) with significant clearance of preformed antibodies (p = 0.04, OR = 56) and lower induction of de novo DSA (p = 0.07, OR = 24). Innovative multifaceted anti‐DSA strategies are required to further improve long‐term survival particularly of liver‐free allografts.

2016 Comprehensive Update of the Banff Working Group on Liver Allograft Pathology: Introduction of Antibody-Mediated Rejection

The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody‐mediated liver allograft rejection at the 11th (Paris, France, June 5–10, 2011), 12th (Comandatuba, Brazil, August 19–23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5–10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody‐mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.

Recovery of Functional Memory T Cells in Lung Transplant Recipients Following Induction Therapy with Alemtuzumab

Profound T‐cell depletion with the monoclonal antibody alemtuzumab facilitates reduced maintenance immunosuppression in abdominal and lung transplantation. While the phenotype of the post‐depletional T cells has been characterized, little is known about their function. In the present study, global and CMV‐specific T‐cell function was assessed longitudinally in 23 lung transplant (LTx) recipients using T‐cell assays (ImmuKnow® and T Cell Memory™ , Cylex, Columbia, MD) during the first year posttransplant after induction therapy. Recovery of mitogen responses were seen at 2 weeks posttransplantation (65%PHA; 58% Con A), despite the low number of circulating T cells (<2%). These responses declined at 4–5 months (24%PHA; 54% Con A) and were partially reconstituted by 9 months (46% PHA; 73% Con A). CMV‐specific responses recovered in 80% of R+ patients as early as 2 weeks posttransplant (n = 5) and 72% of patients had a memory response by 3 months (n = 11). In contrast, only 2 of 5 patients who did not exhibit memory responses pre‐transplant (R–) developed transient CMV‐specific T‐cell responses. Our results show that profound depletion of T cells induced by alemtuzumab spares the functional subset of CMV‐specific memory T cells. Conversely, CMV R– patients predepletion may require a prolonged period of prophylaxis.

Aerosol cyclosporin therapy in lung transplant recipients with bronchiolitis obliterans

The majority of patients who develop bronchiolitis obliterans, after lung transplantation, die within 2–3 yrs after onset since treatment with conventional immunosuppression is typically ineffective. A case/control study was conducted in lung transplant recipients with biopsy-documented bronchiolitis obliterans to determine whether aerosol cyclosporin use contributed to increased survival. The cases comprised 39 transplant recipients who received open-label aerosol cyclosporin treatment in addition to conventional immunosuppression. The controls were transplant recipients treated with conventional immunosuppression alone. There were 51 controls from the University of Pittsburgh Medical Center and 100 from a large multicentric database (Novartis Lung Transplant Database). Forced expiratory volume in one second expressed as a percentage of the predicted value was an independent predictor of survival in all patients with bronchiolitis obliterans. Cox proportional-hazards analysis revealed a survival advantage for aerosol cyclosporin cases compared to the Pittsburgh control group. A survival advantage was also seen when comparing study cases to multicentric controls. Aerosol cyclosporin, given with conventional immunosuppression to lung transplant recipients with bronchiolitis obliterans, provides a survival advantage over conventional therapy alone.

HLA-class II antigen expression in human heart-lung allografts.

Long-term survival in heart-lung transplantation has ben hindered by the development of bronchiolitis obliterans (OB), which is believed to be a manifestation of chronic rejection of the lung. Since HLA-class II antigens are involved in the rejection response, the distribution of the class II products HLA-DR, HLA-DQ, and HLA-DP were studied in normal lung, and in transplanted lung with and without OB, utilizing frozen-section immunohistochemical techniques. All three allelic products are usually expressed on the epithelial, endothelial, and mesenchymal components of the lung. Sequential transbronchial biopsies from 4 recipients before and concurrent with the diagnosis of OB were stained with serial dilutions of monoclonal antibodies to assess the level of expression of the above class II products. Increased levels of HLA-DR and HLA-DP antigens may be seen on the bronchial and bronchiolar epithelium during OB, but the changes are subtle and complicated by many other variables. Additional studies are needed to confirm these preliminary results.