Bidirectional transfer of Anelloviridae lineages between graft and host during lung transplantation

Solid organ transplantation disrupts virus-host relationships, potentially resulting in viral transfer from donor to recipient, reactivation of latent viruses, and new viral infections. Viral transfer, colonization, and reactivation are typically monitored using assays for specific viruses, leaving the behavior of full viral populations (the "virome") understudied. Here we sought to investigate the temporal behavior of viruses from donor lungs and transplant recipients comprehensively. We interrogated the bronchoalveolar lavage and blood viromes during the peritransplant period and 6-16 months posttransplant in 13 donor-recipient pairs using shotgun metagenomic sequencing. Anelloviridae, ubiquitous human commensal viruses, were the most abundant human viruses identified. Herpesviruses, parvoviruses, polyomaviruses, and bacteriophages were also detected. Anelloviridae populations were complex, with some donor organs and hosts harboring multiple contemporaneous lineages. We identified transfer of Anelloviridae lineages from donor organ to recipient serum in 4 of 7 cases that could be queried, and immigration of lineages from recipient serum into the allograft in 6 of 10 such cases. Thus, metagenomic analyses revealed that viral populations move between graft and host in both directions, showing that organ transplantation involves implantation of both the allograft and commensal viral communities.

The Perioperative Lung Transplant Virome: Torque Teno Viruses Are Elevated in Donor Lungs and Show Divergent Dynamics in Primary Graft Dysfunction

Primary graft dysfunction (PGD) is a principal cause of early morbidity and mortality after lung transplantation, but its pathogenic mechanisms are not fully clarified. To date, studies using standard clinical assays have not linked microbial factors to PGD. We previously used comprehensive metagenomic methods to characterize viruses in lung allografts >1 mo after transplant and found that levels of Anellovirus, mainly torque teno viruses (TTVs), were significantly higher than in nontransplanted healthy controls. We used quantitative polymerase chain reaction to analyze TTV and shotgun metagenomics to characterize full viral communities in acellular bronchoalveolar lavage from donor organs and postreperfusion allografts in PGD and non-PGD lung transplant recipient pairs. Unexpectedly, TTV DNA levels were elevated 100-fold in donor lungs compared with healthy adults (p = 0.0026). Although absolute TTV levels did not differ by PGD status, PGD cases showed a smaller increase in TTV levels from before to after transplant than did control recipients (p = 0.041). Metagenomic sequencing revealed mainly TTV and bacteriophages of respiratory tract bacteria, but no viral taxa distinguished PGD cases from controls. These findings suggest that conditions associated with brain death promote TTV replication and that greater immune activation or tissue injury associated with PGD may restrict TTV abundance in the lung.

When Living Donor Liver Allografts Fail: Exploring the Outcomes of Retransplantation Using Deceased Donors

Outcomes of retransplantation after initial living donor liver transplantation (LDLT) are poorly understood. The aim of this study is to better understand the indications, timing, and outcomes of retransplantation after initial LDLT when compared to after initial deceased donor transplantation (DDLT). From 2002 to 2013, 209 retransplant recipients after initial LDLT and 2893 after initial DDLT were identified in Organ Procurement and Transplantation Network/United Network for Organ Sharing. Multivariable logistic models evaluated the association between initial transplant type and 1-year mortality. The most frequent reason for early graft failure (≤14 days) in LDLT recipients was vascular thrombosis (63.6%) versus primary graft failure in initial DDLT recipients (59.1%). LDLT recipients were more often acutely and/or critically ill with a greater proportion of Status 1 (42.6% vs. 27.3%; p < 0.001) and intensive care unit (52.2% vs. 39.9%; p = 0.001) recipients at the time of retransplantation. There was no difference in adjusted 1-year mortality between retransplant recipients after initial LDLT versus DDLT (odds ratio 0.74; 95% confidence interval 0.51-1.08). The proportion of recipients who ultimately required retransplantation for a third time was not different between the two groups (4.8%). Retransplantation outcomes after LDLT are not different from other retransplant procedures, despite recipients having greater acuity of illness and different indications.

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.

Serum lipid expression correlates with function and regeneration following living donor liver transplantation

Following living donor liver transplantation (LDLT; and unlike deceased donor liver transplantation [DDLT]), the liver must rapidly regenerate, and sometimes segmental graft dysfunction (SGD) is observed. Hepatic regeneration requires substantial de novo lipid synthesis, and we previously reported that expression of lipid-related genes is dysregulated in LDLT. Here, we compare serum lipid measurements in 41 LDLT recipients and 43 DDLT recipients at baseline and at serial posttransplant time points. In addition, we examined whether serum lipid/apolipoprotein (apo) levels correlate with the degree of liver regeneration (measured using percent volume increase [%VI] at 3 months) or SGD in LDLT recipients. In contrast to DDLT, lipid levels declined early after LDLT but returned to baseline by 30 days. The odds ratio (OR) for achieving robust regeneration (>90 %VI) was 2.53 (95% confidence interval [CI], 1.15-5.52) for every 1 mg/dL increase in serum apoE at 30 days. The OR of SGD for every year increase in donor age was 1.19 (95% CI, 1.02-1.39), and 0.61 for every 1 mg/dL increase in serum high-density lipoprotein cholesterol at 7 days (95% CI, 0.34-1.11). No associations were detected between preoperative serum lipids/apos in LDLT donors and SGD or %VI in recipients. In conclusion, we suggest that initiation of regeneration prevents the liver from participating fully in lipid transport and metabolism. Inability to meet systemic metabolic needs may result in compromised liver function and SGD. Certain serum lipid concentrations correlate with extent of liver regeneration and function.

Genomic profiles and predictors of early allograft dysfunction after human liver transplantation

Early hepatic allograft dysfunction (EAD) manifests posttransplantation with high serum transaminases, persistent cholestasis, and coagulopathy. The biological mechanisms are poorly understood. This study investigates the molecular mechanisms involved in EAD and defines a gene expression signature revealing different biological pathways in subjects with EAD from those without EAD, a potential first step in developing a molecular classifier as a potential clinical diagnostic. Global gene expression profiles of 30 liver transplant recipients of deceased donor grafts with EAD and 26 recipients without graft dysfunction were investigated using microarrays of liver biopsies performed at the end of cold storage and after graft reperfusion prior to closure. Results reveal a shift in inflammatory and metabolic responses between the two time points and differences between EAD and non-EAD. We identified relevant pathways (PPARα and NF-κB) and targets (such as CXCL1, IL1, TRAF6, TIPARP, and TNFRSF1B) associated with the phenotype of EAD. Preliminary proof of concept gene expression classifiers that distinguish EAD from non-EAD patients, with Area Under the Curve (AUC) >0.80 were also identified. This data may have mechanistic and diagnostic implications for EAD.

Quadrimembral amputation: indications and contraindications for vascularized composite allotransplantation

INTRODUCTION

Quadrimembral amputees, as patients who have lost both upper and lower extremities, may benefit greatly from hand transplantation. The objective of this study is to evaluate the indications and contraindications for transplantation in this subset of patients.

METHODS

A retrospective review was conducted of five quadrimembral amputees evaluated by our program for transplantation. Information collected included age, sex, level of amputations, time since amputations, etiology, level of dependence, medical stability, psychosocial status, and the ability to tolerate immunosuppression. Indications and contraindications for transplantation were reviewed for each patient.

RESULTS

All etiologies were based in extremity ischemia: three from septic shock, one from myocardial infarction, and one from drug overdose. All patients are completely dependent. Of the five patients, two needed further reconstructive surgery and two others had a history of resolved hepatic/renal insufficiency. After thorough evaluation, two patients were selected as potential transplant candidates. They demonstrated strong psychosocial support systems, a thorough understanding of hand transplantation, along with its risks and postoperative requirements. They had also completed a full regimen of rehabilitation along with prosthetic fitting and utilization.

CONCLUSIONS

Clearance for transplantation is based on medical stability, absence of infection or systemic diseases, and strong psychosocial support systems. Contraindications for transplantation are drug dependence and noncompliant behavior. Relative contraindications include a history of hepatic/renal insufficiency which if not resolved may preclude the use of postoperative immunosuppression.

Transplantation genetics: current status and prospects

Over the last decade, advances in genetic technologies have accelerated our understanding of the genetic diversity across individuals and populations. Case-control and population-based studies have led to several thousand genetic associations across a range of phenotypes and traits being unveiled. Despite widespread and successful use of organ transplantation as a curative therapy for organ failure, genetic research has yet to make a major impact on transplantation practice aside from HLA matching. New studies indicate that non-HLA loci, termed minor histocompatibility antigens (mHAs), may play an important role in graft rejection. With several million common and rare polymorphisms observed between any two unrelated individuals, a number of these polymorphisms represent mHAs, and may underpin transplantation rejection. Genetic variation is also recognized as contributing to clinical outcomes including response to immunosuppressants, introducing the possibility of genotype-guided prescribing in the very near future. This review summarizes existing knowledge of the impact of genetics on transplantation outcomes and therapeutic responses, and highlights the translational potential that new genomic knowledge may bring to this field.

The role of donor-specific HLA alloantibodies in liver transplantation

The impact of donor-specific HLA alloantibodies (DSA) on short- and long-term liver transplant outcome is not clearly defined. While it is clear that not all levels of allosensitization produce overt clinical injury, and that liver allografts possess some degree of alloantibody resistance, alloantibody-mediated adverse consequences are increasingly being recognized. To better define the current state of this topic, we assembled experts to provide insights, explore controversies and develop recommendations for future research on the consequences of DSA in liver transplantation. This article summarizes the proceedings of this inaugural meeting. Several insights emerged. Acute antibody-mediated rejection (AMR), although rarely diagnosed, is increasingly understood to overlap with T cell-mediated rejection. Isolated liver allograft recipients are at increased risk of early allograft immunologic injury when preformed DSA are high titer and persist posttransplantation. Persons who undergo simultaneous liver-kidney transplantation are at risk of renal AMR when Class II DSA persist posttransplantation. Other under-appreciated DSA associations include ductopenia and fibrosis, plasma cell hepatitis, biliary strictures and accelerated fibrosis associated with recurrent liver disease. Standardized DSA testing and diagnostic criteria for both acute and chronic AMR are needed to distil existing associations into etiological processes in order to develop responsive therapeutic strategies.

Donor hemosiderosis does not affect liver function and regeneration in the setting of living donor liver transplantation

Living donor liver transplantation (LDLT) demands a careful assessment of abnormal findings discovered during the evaluation process to determine if there will be any potential risks to the donor or recipient. Varying degrees of elevated hepatic iron levels are not uncommonly seen in otherwise healthy individuals. We questioned whether mild expression of hemosiderin deposition presents a safety concern when considering outcomes of living donation for both the donor and the recipient. We report on three LDLT patients who were found to have low- to moderate-grade hemosiderin deposition on liver biopsy. All other aspects of their evaluation proved satisfactory, and the decision was made to proceed with donation. There were no significant complications in the donors, and all demonstrated complete normalization of liver function postoperatively, with appropriate parenchymal regeneration. The recipients also had unremarkable postoperative recovery. We conclude that these individuals can be considered as potential donors after careful evaluation.

Simultaneous thoracic and abdominal transplantation: can we justify two organs for one recipient?

Simultaneous thoracic and abdominal (STA) transplantation is controversial because two organs are allocated to a single individual. We studied wait-list urgency, and whether transplantation led to successful outcomes. Candidates and recipients for heart-kidney (SHK), heart-liver (SHLi), lung-liver (SLuLi) and lung-kidney (SLuK) were identified through the United Network for Organ Sharing (UNOS) and outcomes were compared to single-organ transplantation. Since 1987, there were 1801 STA candidates and 836 recipients. Wait-list survival at 1- and 3 years for SHK (67.4%, 40.8%; N = 1420), SHLi (65.7%, 43.6%; N = 218) and SLuLi (65.7%, 41.0%; N = 122), was lower than controls (p < 0.001), whereas for SLuK (65.0%, 51.6%; N = 41) it was comparable (p = 0.34). All STA groups demonstrated similar 1- and 5 years posttransplant survival to thoracic controls. Compared to abdominal controls, 1- and 5 years posttransplant survival in SHK (85.3%, 74.0%; N = 684), SLuLi (75.5%, 59.0%; N= 42) and SLuK (66.7%, 55.6%; N = 18) was decreased (p < 0.01), but SHLi (85.9%, 74.3%; N = 92) was comparable (p = 0.81). In summary, STA candidates had greater risk of wait-list mortality compared to single-organ candidates. STA outcomes were similar to thoracic transplantation; however, outcomes were similar to abdominal transplantation for SHLi only. Although select patients benefit from STA, risk-exposure variables for decreased survival should be identified, aiming to eliminate futile transplantation.

Gene set enrichment analysis identifies key innate immune pathways in primary graft dysfunction after lung transplantation

We hypothesized alterations in gene expression could identify important pathways involved in transplant lung injury. Broncho alveolar lavage fluid (BALF) was sampled from donors prior to procurement and in recipients within an hour of reperfusion as part of the NIAID Clinical Trials in Organ Transplantation Study. Twenty-three patients with Grade 3 primary graft dysfunction (PGD) were frequency matched with controls based on donor age and recipient diagnosis. RNA was analyzed using the Human Gene 1.0 ST array. Normalized mRNA expression was transformed and differences between donor and postreperfusion values were ranked then tested using Gene Set Enrichment Analysis. Three-hundred sixty-two gene sets were upregulated, with eight meeting significance (familywise-error rate, FWER p-value <0.05), including the NOD-like receptor inflammasome (NLR; p < 0.001), toll-like receptors (TLR; p < 0.001), IL-1 receptor (p = 0.001), myeloid differentiation primary response gene 88 (p = 0.001), NFkB activation by nontypeable Haemophilus influenzae (p = 0.001), TLR4 (p = 0.008) and TLR 9 (p = 0.018). The top five ranked individual transcripts from these pathways based on rank metric score are predominantly present in the NLR and TLR pathways, including IL1β (1.162), NLRP3 (1.135), IL1α (0.952), IL6 (0.931) and CCL4 (0.842). Gene set enrichment analyses implicate inflammasome-mediated and innate immune signaling pathways as key mediators of the development of PGD in lung transplant patients.

Outcomes of living and deceased donor liver transplant recipients with hepatocellular carcinoma: results of the A2ALL cohort

Hepatocellular carcinoma (HCC) represents an increasing fraction of liver transplant indications; the role of living donor liver transplant (LDLT) remains unclear. In the Adult-to-Adult Living Donor Liver Transplantation Cohort Study, patients with HCC and an LDLT or deceased donor liver transplant (DDLT) for which at least one potential living donor had been evaluated were compared for recurrence and posttransplant mortality rates. Mortality from date of evaluation of each recipient's first potential living donor was also analyzed. Unadjusted 5-year HCC recurrence was significantly higher after LDLT (38%) than DDLT (11%), (p = 0.0004). After adjustment for tumor characteristics, HCC recurrence remained significantly different between LDLT and DDLT recipients (hazard ratio (HR) = 2.35; p = 0.04) for the overall cohort but not for recipients transplanted following the introduction of MELD prioritization. Five-year posttransplant survival was similar in LDLT and DDLT recipients from time of transplant (HR = 1.32; p = 0.27) and from date of LDLT evaluation (HR = 0.73; p = 0.36). We conclude that the higher recurrence observed after LDLT is likely due to differences in tumor characteristics, pretransplant HCC management and waiting time.

Clinical features and natural history of hepatocellular adenomas: the impact of obesity

BACKGROUND

Hepatocellular adenoma is a benign tumour associated with bleeding and malignant transformation. Obesity has been linked to hepatic tumourigenesis.

AIM

To evaluate the presentation of hepatocellular adenoma in obesity, and the impact of obesity on the clinical course.

METHODS

Records of 60 consecutive patients (between 2005 and 2010) with a diagnosis of hepatocellular adenoma from a single tertiary centre were analysed.

RESULTS

Fifty six of 60 patients were women, median age was 36years, 75% had history of contraceptive use, 18% were overweight and 55% were obese (BMI ≥30kg/m(2) ). Majority (63%) were asymptomatic; seven patients presented with bleeding. Single (28%) and multiple adenomas (72%) were encountered; size ranged from 1 to 19.7cm. Obesity was more often associated with multiple adenomas (85% vs. 48%, P=0.005), bilobar distribution (67% vs. 33%, P=0.01), lower serum albumin (P=0.007) and co-morbidities of fatty liver (P=0.006), diabetes (P=0.003), hypertension (P=0.006) and dyslipidemia (P=0.03). During median follow-up of 2.6years, there were no instances of bleeding, malignant transformation or death. Thirty four patients underwent therapeutic intervention (17 surgical resection, nine transarterial embolization and eight both interventions sequentially). The rate of complete resection of adenoma(s) was significantly lower in obese patients (8% vs. 69%, P=0.004). In the 26 patients without intervention, tumour size progression was more frequently observed in obese patients (33% vs. 0%, P=0.05). Three of 15 obese patients (20%) lost ≥5% body weight and there was no progression in the liver lesions.

CONCLUSIONS

Obesity and features of metabolic syndrome were frequently observed in hepatocellular adenoma. Multiple and bilobar adenomas were more frequent in obese patients. Among patients who were conservatively managed, tumour progression was more often associated with obesity.

Database comparison of the adult-to-adult living donor liver transplantation cohort study (A2ALL) and the SRTR U.S. Transplant Registry

Data submitted by transplant programs to the Organ Procurement and Transplantation Network (OPTN) are used by the Scientific Registry of Transplant Recipients (SRTR) for policy development, performance evaluation and research. This study compared OPTN/SRTR data with data extracted from medical records by research coordinators from the nine-center A2ALL study. A2ALL data were collected independently of OPTN data submission (48 data elements among 785 liver transplant candidates/recipients; 12 data elements among 386 donors). At least 90% agreement occurred between OPTN/SRTR and A2ALL for 11/29 baseline recipient elements, 4/19 recipient transplant or follow-up elements and 6/12 donor elements. For the remaining recipient and donor elements, >10% of values were missing in OPTN/SRTR but present in A2ALL, confirming that missing data were largely avoidable. Other than variables required for allocation, the percentage missing varied widely by center. These findings support an expanded focus on data quality control by OPTN/SRTR for a broader variable set than those used for allocation. Center-specific monitoring of missing values could substantially improve the data.

Response assessment of HCC undergoing chemoembolization by necrosis-adjusted models

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Background: Chemoembolization (CE) is an accepted therapy for unresectable HCC. As treated tumors may not shrink in size, response assessment via measurement of the enhancing tumor (EASL) has been proposed as an alternate to whole tumor (RECIST) measures. However, the reliability of this model has not been tested in clinical practice. Methods: We identified 29 HCC patients treated with CE with known overall survival (OS) in whom MRI before and after initial CE therapy was available for review. Three radiologists evaluated the imaging, measuring the largest liver lesion in three dimensions and the largest enhancing region in two dimensions. Readers also assessed percent tumor necrosis and overall tumor response qualitatively. Response models in 1-, 2-, or 3- dimensions, with or without necrosis adjustment, were created to assign patients to CR/PR/SD/PD classes, based on majority classification. Predictive value for OS was assessed for PD vs. other, and for PR/CR vs. SD/PD by the Students’ t-test. Inter-reader concordance was assessed by the Fleiss κ statistic. Results: For non-necrosis adjusted models, OS for progressors vs. non-progressors was statistically significant (p values: 0.0002–0.04), but could not identify early responders. Necrosis adjusted models failed to identify early progressors, but identified responders with improved OS (p values: 0.02–0.12). Inter-reader concordance was higher for necrosis adjusted models (κ range: 0.36–0.52) than for non-necrosis adjusted models (0.16–0.23). Viable tumor response by a two-dimensional product was superior to a one-dimensional diameter for predicting OS (p=0.04 vs. 0.74), and demonstrated higher inter-reader concordance (κ=0.46 vs. 0.30). Qualitative assessment of hepatic tumor could predict differences in OS for both PD vs. others (p=0.0001) and responders vs. non-responders (p=0.04), with acceptable inter-reader concordance (κ=0.34). Conclusions: Two- dimensional, but not one-dimensional, viable tumor measurement can identify response of HCC to chemoembolization and predict OS. Models which incorporate qualitative reader assessment of tumor necrosis may be more flexible than direct measures of viable tumor, and should be considered as alternatives for tumor assessment in chemoembolization.

No significant financial relationships to disclose.

Plasma cytokines and chemokines in primary graft dysfunction post-lung transplantation

Primary graft dysfunction (PGD) after lung transplantation causes significant morbidity and mortality. We aimed to determine the role of cytokines and chemokines in PGD. This is a multicenter case-control study of PGD in humans. A Luminex analysis was performed to determine plasma levels of 25 chemokines and cytokines before and at 6, 24, 48 and 72 h following allograft reperfusion in 25 cases (grade 3 PGD) and 25 controls (grade 0 PGD). Biomarker profiles were evaluated using a multivariable logistic regression and generalized estimating equations. PGD cases had higher levels of monocyte chemotactic protein-1 (MCP-1)/chemokine CC motif ligand 2 (CCL2) and interferon (IFN)-inducible protein (IP-10)/chemokine CXC motif ligand 10 (CXCL10) (both p < 0.05), suggesting recruitment of monocytes and effector T cells in PGD. In addition, PGD cases had lower levels of interleukin (IL-13) (p = 0.05) and higher levels of IL-2R (p = 0.05). Proinflammatory cytokines, including tumor necrosis factor (TNF)-alpha, and IFN-gamma decreased to very low levels after transplant in both PGD cases and controls, exhibiting no differences between the two groups. These findings were independent of clinical variables including diagnosis in multivariable analyses, but may be affected by cardiopulmonary bypass. Profound injury in clinical PGD is distinguished by the upregulation of selected chemokine pathways, which may useful for the prediction or early detection of PGD if confirmed in future studies.

Liver transplantation in the setting of extra-hepatic malignancy: two case reports

Candidates for liver transplantation (OLT) may be found to have an incidental extrahepatic tumor, which is amenable to resection, and may be associated with variable long-term survival. Issues to be considered include: (1) Whether it is possible to define a tumor stage and survival expectancy, which makes the patient an acceptable transplant candidate; (2) Whether cancer surgery should be preformed prior, during, or after OLT; (3) Whether the recipient be placed on immunosuppression that is tailored to address concern related to cancer recurrence. These issues are illustrated in the context of OLT and nephrectomy for renal cell carcinoma (RCC). Two patients underwent a simultaneous OLT and curative radical nephrectomy for stage 1 RCC that was incidentally discovered during OLT evaluation, one of whom received a simultaneous kidney transplant. At 51 and 14 months postoperatively, the patients are alive and healthy, with no tumor recurrence. In selected extrahepatic malignancies, simultaneous curative resection and OLT may provide the optimal outcome. This is justifiable when curative cancer-related life expectancy exceeds OLT-expected graft and patient survival. Concomitant transplantation and cancer surgery provides an acceptable cancer-free survival, avoiding the high morbidity observed when cancer resection is done in the presence of decompensated liver disease.

Successful liver, kidney, and pancreas transplantation from a donor with cerebral emboli from a left atrial myxoma

Although transmission and engraftment of donor-derived malignancies is rare in recipients of solid organ transplants, it is associated with unfavorable allograft and patient survival. Therefore, a recent history of malignancy is considered a contraindication to organ donation. Although atrial myxomas are benign cardiac tumors of stromal origin, they can lead to systemic embolization with ectopic myxoma formation. We report successful liver, kidney, and pancreas transplantation into 3 recipients from a donor with cerebral emboli from a left atrial myxoma. Eighteen months after transplantation, all 3 patients enjoy good allograft function and are free of donor-derived atrial myxoma. Although the duration of follow-up in this report is limited, we suggest that the presence of atrial myxoma should not be viewed as an absolute contraindication to organ recovery, particularly in view of the shortage of organ donors and the attendant morbidity and mortality for patients on waiting lists.

Pattern of alloimmune response in second same donor allografts after induction of tolerance using CTLA4Ig

BACKGROUND

The pattern of allograft acceptance in the presence of costimulatory blockade is manifested by the sequential appearance of Th1 cells, followed by Th2 cells. The aim of this study was to examine whether this phenomenon repeats itself after second same donor allotransplantation, hoping to determine whether acceptance in this setting provokes a predominance of the Th2 response.

METHODS

Tolerance was achieved by transplantation of CTLA4Ig-transduced ACI liver allografts in Lewis recipients. Recipient long-term survivors received a second transplant, consisting of a cervical heterotopic heart from the same ACI donor strain. Animals were sacrificed at predetermined intervals following the second transplant and the heart and liver were processed for histology and cytokine mRNA expression.

RESULTS

Recipients of CTLA4Ig-transduced livers survived indefinitely. Rechallenge with same donor strain second allograft was manifested by an anergic immune response in the second cardiac allograft, and a very mild transient infiltrate within the first accepted liver graft. Cardiac function was maintained with resolution of all infiltrates. The cytokine cascade was activated within the allografts; however, the pattern of acceptance was not associated with predominance of a specific Th subtype.

CONCLUSIONS

The pattern of acceptance of an allograft following CTLA4Ig-mediated costimulatory blockade is not related to long-term predominance of Th2 cells, a phenomenon that may be unique to the setting of a tolerant liver. It may be likely that the infiltrating lymphocytes that are dominant in the second graft are suppressed by other memory mechanisms.

Role of plasmapheresis in the management of acute hepatic failure in children

OBJECTIVE

To assess the efficacy of plasmapheresis in the treatment of children with acute hepatic failure.

SUMMARY BACKGROUND DATA

Acute liver failure is expressed with severe encephalopathy, coagulopathy, and subsequent multisystem organ failure, resulting in a high death rate. Liver transplantation is considered the best option, with long-term 1-year survival rates exceeding 88%. It has been suggested that plasmapheresis may improve coagulopathy and prevent bleeding complications while maintaining adequate fluid, electrolyte, and acid-base balance.

METHODS

Forty-nine patients with acute liver failure underwent a total of 243 therapeutic plasma exchanges (TPE). Indications for treatment included candidacy for liver transplant and prolonged prothrombin time. Pheresis was performed daily until the patient recovered, died, or was transplanted. Four patients were anhepatic during pheresis.

RESULTS

Coagulation profiles after TPE significantly improved compared with mean preexchange values while maintaining euvolemia. No bleeding episodes were observed during the course of treatment. There was no sustained improvement in neurologic function. Spontaneous recovery was observed in three patients; the remaining either underwent transplantation (32/49) or were not considered transplant candidates because of irreversible neurologic insults (11/49) or sepsis (3/49).

CONCLUSION

For children with acute liver failure, TPE is extremely effective in preventing life-threatening bleeding while maintaining appropriate volume status in small children. This method of treatment has no effect on the neurologic complications of liver failure and has no impact on the ability of the liver to regenerate.

Modified AdCTLA-4 vector blocks alloimmune response in vitro

BACKGROUND

Gene transfer of the costimulatory blockade molecule CTLA-4Ig into cold-preserved rat liver allografts results in indefinite allograft survival. Despite local delivery, this mode of immunomodulation is associated with systemic immunosuppression. In an effort to restrict immunosuppression to the graft, we have constructed a novel adenoviral vector, AdCTLA-4ex-TAG, in which the Ig sequence of CTLA-4Ig DNA has been deleted to destabilize the gene product to promote rapid extrahepatic degradation while maintaining its immunosuppressive activity within the graft milieu.

METHODS

(1) Vector construction. CTLA-4 extracellular binding domain (CTLA-4ex) was prepared by PCR-based cloning methods and fused in frame to a genetic element encoding an epitope TAG allowing identification of the transgene product CTLA-4exTAG. CTLA-4exTAG was subcloned into a shuttle vector enabling isolation of AdCTLA-4exTAG. (2) In vitro transfection: AdCTLA-4exTAG was transfected into MH(1)C(1) cells and then supernatant was recovered for Western blot analysis. (3) In vitro alloimmune response was characterized by CFSE proliferation assay. (4) Extrahepatic effect of AdCTLA-4exTAG was characterized by the ability to control tumor growth after implantation of a regressive, immune sensitive cancer cell line (REGb) in the skin of BDIX rats after liver transduction with AdCTLA-4exTAG.

RESULTS

Expression and secretion of the recombinant protein were documented by Western blot after infection of the MH(1)C(1) cell line() with AdCTLA-4exTAG. Addition of infected MH(1)C(1) cell supernatant resulted in abrogation of alloimmune response as shown by markedly diminished division of CD4(+) T cells in a CFSE proliferation assay. Extrahepatic tumor regressed normally after liver transduction with AdCTLA-4exTAG.

CONCLUSIONS

These results show efficient in vitro expression of CTLA-4exTAG after transfection with AdCTLA-4exTAG. The modified protein retains its ability to abrogate in vitro alloimmune response. Efficient control of extrahepatic tumor growth after liver-directed delivery of AdCTLA-4exTAG suggests that the immunosuppressive effect of this vector is restricted to the liver. These results set the ground for the utilization of this novel adenoviral vector in the transplant setting.

Clinical utility of monitoring tacrolimus blood concentrations in liver transplant patients

The relationship between the dose of tacrolimus, trough tacrolimus blood concentration, and selected clinical endpoints (acute rejection, nephrotoxicity, and other toxicities) were examined in a prospective, multicenter clinical trial to validate the use of an enzyme-linked immunosorbent assay (ELISA) for monitoring whole-blood concentrations of tacrolimus in liver transplant patients. A total of 111 subjects from six transplant centers were evaluated over 12 weeks posttransplantation. In addition to trough tacrolimus blood concentrations, hematocrit, ALT, AST, GGTP, alkaline phosphatase, total bilirubin, serum creatinine, BUN, serum potassium, serum magnesium, blood glucose, and serum albumin were also measured. The relationship between trough tacrolimus blood concentrations and clinical endpoints was analyzed using both a logistic regression model and a Cox proportional hazard model. By logistic regression analysis, a statistically significant (p = 0.0465) relationship between increasing trough tacrolimus blood concentrations and decreasing risk of acute rejection was demonstrated over a 7-day time window. Nephrotoxicity and other toxicities also demonstrated statistically significant relationships with trough tacrolimus blood concentrations. The results of the Cox analysis were consistent with the logistic regression analysis. Using receiver operator characteristic curves, trough tacrolimus concentrations as measured by the ELISA method were able to differentiate the occurrence of nephrotoxicity and toxicity from nonevents. To minimize nephrotoxicity of tacrolimus, it is necessary to maintain trough blood concentrations below 15 ng/ml. This study demonstrates that the ELISA method used to measure tacrolimus blood concentrations in this study provides information of predictive value for managing the risk of nephrotoxicity, other toxicity, and rejection in liver transplant patients.

Liver transplantation at the University of Pennsylvania and the Children's Hospital of Philadelphia

The liver transplant program at the University of Pennsylvania and the Children's Hospital of Philadelphia experienced healthy growth in its clinical activity in the past 5 years. Patterns of referral and patient evaluation were established, care of patients while waiting on the list or being followed after transplantation was streamlined. We are now achieving excellent outcomes while transplanting relatively sicker patients. Innovative surgical procedures are implemented resulting in more efficient utilization of cadaveric and living-donor liver grafts. The protocols that are used for patient care are more standard, yet flexible and accommodate recent advancement in transplantation immunobiology. This progress of the clinical program was enhanced by careful preservation of the academic mission of the institution, which encourages the liver transplant faculty to be involved in NIH-supported clinical and basic science research.

Partnership

Individuals are called partners when it is in their best interest to help each other, if by doing so they increase the probability of being together in the future when, for similar reasons, they will continue to help each other. Kinsmen or individuals who often face (hedonic) situations in which helping is the dominating strategy are committed to help each other. Partnership may develop among them since the loss of the other means the loss of a guaranteed helper. Thus, they may be willing to take additional risks to help each other. Partnership may occur among unrelated individuals and with no hedonic situations. Partnership creates bonds between partners which may be much stronger than those between kinsmen; an individual may take more risks for his partner than he will ever take for a kin. Partnership may evolve without the sophistication and memory required for reciprocation altruism. Although kin selection, partnership and reciprocation are likely to appear fused as the causes for altruism, we argue that it may be possible to distinguish between them in some situations. We show that as the partners get older partnership may become less important to them. We also show that like cooperation, and for analogous reasons, malice may evolve among partners so that each will be willing to take additional risks in order to eliminate the other.

The fate of liver grafts declined for subjective reasons and transplanted out of a local organ procurement organization

BACKGROUND

Decisions made by transplant surgeons to decline liver grafts for local use are based on both objective and ill-defined subjective parameters. These livers may be offered and subsequently transplanted at non-local centers. We analyzed the fate of these exported livers, focusing on the outcome of grafts declined for subjective reasons. The aim is to determine whether local surgeons' concerns about inferior graft function are justified.

METHODS

Over a 3-year period, 13.3% of 555 livers in our organ procurement organization (OPO) were exported and transplanted out of the local area. Donor data and reason for decline were obtained from an extensive OPO database. Objective reasons for decline were based on no appropriate matched recipient due to donor size, serologies, or malignancy with potential for spread. Subjective parameters were related to the procuring surgeon's assessment and included variables such as medical and social history, abnormal liver enzymes, older age, organ visualization, and biopsy. Recipient data were obtained from questionnaires sent to outside transplant centers.

RESULTS

There was a significantly higher rate of nonfunction in the subjective group (17.1%), compared to the objective group (0%). One-year graft and patient survival were 79 and 83% for the objective group and 59 and 68% for the subjective group (P=NS). When donors declined for medical/social history were excluded from the subjective group, leaving only grafts declined based solely on the surgeon's assessment of graft quality, there is a significant difference in graft survival (79% for objective and 46% for this subjective subgroup, P=0.03).

CONCLUSIONS

Livers declined for local use based on subjective assessment by the procuring surgeon have a high nonfunction rate, associated with a high morbidity. Therefore, the use of these grafts should be restricted to recipients at the most urgent status.

Endoscopic management of postoperative biliary complications in orthotopic liver transplantation

BACKGROUND

Surgery, percutaneous cholangiography, and endoscopic retrograde cholangiopancreatography (ERCP) have been used in the management of biliary complications after orthotopic liver transplantation with varied results. We assessed the role of ERCP in the diagnosis, treatment, and outcome of post-orthotopic liver transplantation biliary complications.

METHODS

We retrospectively reviewed the records of 260 patients who underwent orthotopic liver transplantation. We examined the number of patients referred for ERCP and the indication, diagnosis, therapeutic intervention, success, and complication rate of ERCP post orthotopic liver transplantation. We compared the survival and retransplantation rates of the patients who underwent ERCP with a control group of post-orthotopic liver transplantation patients not undergoing ERCP.

RESULTS

Of the 260 patients undergoing orthotopic liver transplantation, 64 (24.6%) underwent 137 ERCPs. Two categories of indications for ERCP were identified: bile leak (n = 31) and obstruction (n = 39). ERCP identified the site of the bile leak in 27 of 31 cases (87.1%) and the leak was treated by endoscopic means in 26 of 31 (83.9%). Treatment success differed significantly based on location of the leak (T tube, 95.2% vs. anastomosis, 42.9%; p = 0. 009). ERCP identified the site of obstruction in 37 of 39 cases (94. 9%) and obstruction was relieved by endoscopic means in 25 of 35 cases (71.4%). ERCP was significantly less successful in the treatment of biliary casts (25.0%, p = 0.048). There was no difference in survival or retransplantation between patients who did and did not undergo ERCP.

CONCLUSION

ERCP should be the primary method for diagnosis and treatment of post-orthotopic liver transplantation biliary complications. Endoscopic therapy is safe and effective for the majority of post-orthotopic liver transplantation complications and temporizes management for those complications that may require surgery.

Supraceliac aortic pseudoaneurysms after liver transplantation in infants

BACKGROUND

Reconstruction of the hepatic artery in infants undergoing liver transplantation presents challenging vascular situations. Microvascular techniques ensure arterial blood flow via small caliber vessels but are insufficient when inflow is poor. In these situations, the use of allogeneic grafts to the supraceliac aorta have been advocated. The development of a pseudoaneurysm at the supraceliac aortic suture line requires urgent repair and restoration of arterial flow to the graft.

METHODS

Our study was based on case reports and review of the literature.

RESULTS

Definitive diagnosis and successful repair of supraceliac pseudoaneurysm was accomplished in two infants after transplantation.

CONCLUSION

We advocate a thoracoabdominal retroperitoneal approach, which provides safe control of the aorta and primary repair or patching of the diseased aortic segment, and also provides access for hepatic revascularization via placement of an infrarenal graft. Thrombosis of the artery and subsequent liver necrosis are indications for retransplantation.

Percutaneous thrombolysis and stent placement for the treatment of portal vein thrombosis after liver transplantation: long-term follow-up

BACKGROUND

The durable use of percutaneous minimally invasive techniques for the treatment of portal venous thrombosis after liver transplant has not been widely described. This report illustrates two cases in which percutaneous thrombolysis, angioplasty, and endovascular stent placement were successfully used to treat portal vein thrombosis in patients with recent liver transplants.

METHODS

Liver dysfunction was initially manifested by the elevation of liver enzymes or the development of marked ascites and confirmed in both cases by sonography and angiography. The occluded portal vein was accessed by either a transjugular transhepatic puncture or direct transhepatic catheterization. Intraportal thrombolytic infusion, angioplasty, and stent placement were accomplished without complication.

RESULTS

At the most recent follow-up, portal vein patency had been maintained for 2.5 and 4.5 years.

CONCLUSIONS

These results demonstrate the technical feasibility and long-term patency of angioplasty and endovascular stent placement for the treatment of portal vein thrombosis in liver transplant recipients.