Real-time monitoring of acute liver-allograft rejection using the Banff schema

Evaluation of Vitamin D Levels in Children With Liver Transplant

OBJECTIVES

Vitamin D deficiency is common in pediatric chronic liver disease despite oral replacement. We evaluated vitamin D deficiency before and after liver transplant and the relationship between posttransplant and pretransplant vitamin D deficiency and graft rejection.

MATERIALS AND METHODS

Pediatric recipients with chronic liver disease (N =138) were divided into 4 groups: cholestatic liver diseases, cirrhosis, metabolic disorders, and acute liver failure. Pretransplant and posttransplant vitamin D levels, liver function tests, Pediatric End-Stage Liver Disease scores, rejection activity index scores by graft liver biopsy, and posttransplant patient survival were recorded.

RESULTS

There were 62 (45%) female and 76 (55%) male participants (mean transplant age, 6.1 ± 5.6 years). Pretransplant mean available vitamin D of 90 patients was 25.2 ± 20.9 ng/mL, with 36 (40%) within reference range. Posttransplant level for 109 patients was 27.3 ± 18 ng/mL, with 64 (58.7%) within reference range. Pretransplant and posttransplant levels were available for 61 patients, and mean pretransplant levels were lower than posttransplant levels (23.7 ± 19.3 vs 28.3 ± 16.9 ng/mL; P = .01). Patients with cholestatic liver disease had lower pretransplant vitamin D levels (P = .04), which disappeared after transplant. Pretransplant vitamin D levels were positively correlated with serum albumin levels (r = 0.20) in all patients and negatively correlated with total/direct bilirubin (r = 0.29 and r = -0.30) in those with liver diseases and cirrhosis. No correlations were found between pretransplant vitamin D levels and Pediatric End-Stage Liver Disease scores, rejection activity index scores, and posttransplant mortality.

CONCLUSIONS

Vitamin D deficiency is prevalent in pediatric chronic liver disease before and after transplant, especially for cholestatic liver diseases. However, no association between vitamin D levels and liver graft rejection or patient survival was noted. We recommend close monitoring and individualized vitamin D supplementation before and after liver transplant.

Detrimental impact of early biopsy-proven rejection in liver transplantation

Existing literature offers conflicting conclusions about whether early acute cellular rejection influences long-term outcomes in liver transplantation. We retrospectively collected donor and recipient data on all adult, first-time liver transplants performed at a single center between 2008 and 2020. We divided this population into two cohorts based on the presence of early biopsy-proven acute cellular rejection (EBPR) within the first 90 days post-transplant and compared outcomes between the groups. There were 896 liver transplants that met inclusion criteria with 112 cases (12.5%) of EBPR. Recipients who developed EBPR had higher biochemical Model for End-Stage Liver Disease scores (28 vs. 24, p < .01), but other donor and recipient characteristics were similar. Recipients with EBPR had similar overall survival compared to patients without EBPR (p = .09) but had decreased graft survival (p < .05). EBPR was also associated with decreased time to first episode of late (> 90 days post-transplant) rejection (p < .0001) and increased vulnerability to bacterial and viral infection (p < .05). In subgroup analysis of recipients with autoimmune indications for liver transplantation, EBPR had a more pronounced association with patient death (hazard ratio [HR] 3.9, p < .05) and graft loss (HR 4.0, p < .01). EBPR after liver transplant is associated with inferior graft survival, increased susceptibility to late rejections, and increased vulnerability to infection.

Liver transplantation immunology: Immunosuppression, rejection, and immunomodulation

Outcomes after liver transplantation have continuously improved over the past decades, but long-term survival rates are still lower than in the general population. The liver has distinct immunological functions linked to its unique anatomical configuration and to its harbouring of a large number of cells with fundamental immunological roles. The transplanted liver can modulate the immunological system of the recipient to promote tolerance, thus offering the potential for less aggressive immunosuppression. The selection and adjustment of immunosuppressive drugs should be individualised to optimally control alloreactivity while mitigating toxicities. Routine laboratory tests are not accurate enough to make a confident diagnosis of allograft rejection. Although several promising biomarkers are being investigated, none of them is sufficiently validated for routine use; hence, liver biopsy remains necessary to guide clinical decisions. Recently, there has been an exponential increase in the use of immune checkpoint inhibitors due to the unquestionable oncological benefits they provide for many patients with advanced-stage tumours. It is expected that their use will also increase in liver transplant recipients and that this might affect the incidence of allograft rejection. Currently, the evidence regarding the efficacy and safety of immune checkpoint inhibitors in liver transplant recipients is limited and cases of severe allograft rejection have been reported. In this review, we discuss the clinical relevance of alloimmune disease, the role of minimisation/withdrawal of immunosuppression, and provide practical guidance for using checkpoint inhibitors in liver transplant recipients.

T-cell infiltrate intensity is associated with delayed response to treatment in late acute cellular rejection in pediatric liver transplant recipients

BACKGROUND

Late acute cellular rejection (ACR) is associated with donor-specific antibodies (DSA) development, chronic rejection, and allograft loss. However, accurate predictors of late ACR treatment response are lacking. ACR is primarily T-cell mediated, yet B cells and plasma cells (PC) also infiltrate the portal areas during late ACR. To test the hypothesis that the inflammatory milieu is associated with delayed response (DR) to rejection therapy, we performed a single-center retrospective case-control study of pediatric late liver ACR using multiparameter immunofluorescence for CD4, CD8, CD68, CD20, and CD138 to identify immune cell subpopulations.

METHODS

Pediatric liver transplant recipients transplanted at <17 years of age and treated for biopsy-proven late ACR between January 2014 and 2019 were stratified into rapid response (RR) and DR based on alanine aminotransferase (ALT) normalization within 30 days of diagnosis. All patients received IV methylprednisolone as an initial rejection treatment. Immunofluorescence was performed on archived formalin-fixed paraffin embedded (FFPE) liver biopsy tissue.

RESULTS

Liver biopsies from 60 episodes of late ACR in 54 patients were included in the analysis, of which 33 were DR (55%). Anti-thymocyte globulin was only required in the DR group. The frequency of liver-infiltrating CD20+ and CD8+ lymphocytes and the prevalence of autoantibodies were higher in the DR group. In univariate logistic regression analysis, serum gamma-glutamyl transpeptidase (GGT) level at diagnosis, but not ALT, Banff score or presence of DSA, predicted DR.

CONCLUSIONS

Higher serum GGT level, presence of autoantibodies, and increased CD8+ T-cell infiltration portends DR in late ACR treatment in children.

Banff 2016 Global Assessment and Quantitative Scoring for T Cell-Mediated Liver Transplant Rejection are Interchangeable

Introduction. Histopathological assessment of liver biopsies is the current “gold standard” for diagnosing graft dysfunction after liver transplantation (LT), as graft dysfunction can have nonspecific clinical presentations and inconsistent patterns of liver biochemical dysfunction. Most commonly, post-LT, graft dysfunction within the first year, is due to acute T-cell mediated rejection (TCMR) which is characterised histologically by the degree of portal inflammation (PI), bile duct damage (BDD), and venous endothelial inflammation (VEI). This study aimed to establish the relationship between global assessment, which is the global grading of rejection using a “gestalt” approach, and the rejection activity index (RAI) of each component of TCMR as described in revised Banff 2016 guidelines. Methods. Liver biopsies (n = 90) taken from patients who underwent LT in 2015 and 2016 at the Australian National Liver Transplant Unit were identified from the electronic medical records. All biopsy slides were microscopically graded by at least two assessors independently using the revised 2016 Banff criteria. Data were analysed using IBM SPSS v21. A Fisher–Freeman–Halton test was performed to assess the correlation between the global assessment and the RAI scores for each TCMR biopsy. Results. Within the cohort, 60 (37%, n = 164) patients underwent at least 1 biopsy within 12 months after LT. The most common biopsy outcome (total n = 90) was acute TCMR (64, 71.1%). Global assessment of TCMR slides strongly positively correlated with PI ( $p$ value <0.001), BDD ( $p$ value <0.001), VEI ( $p$ value <0.001), and total RAI ( $p$ value <0.001). Liver biochemistry of patients with TCMR significantly improved within 4 to 6 weeks post-biopsy compared to the day of the biopsy. Conclusion. In acute TCMR, global assessment and total RAI are strongly correlated and can be used interchangeably to describe the severity of TCMR.

New Approaches to the Diagnosis of Rejection and Prediction of Tolerance in Liver Transplantation

Immunosuppression after liver transplantation is essential for preventing allograft rejection. However, long-term drug toxicity and associated complications necessitate investigation of immunosuppression minimization and withdrawal protocols. Development of such protocols is hindered by reliance on current paradigms for monitoring allograft function and rejection status. The current standard of care for diagnosis of rejection is histopathologic assessment and grading of liver biopsies in accordance with the Banff Rejection Activity Index. However, this method is limited by cost, sampling variability, and interobserver variation. Moreover, the invasive nature of biopsy increases the risk of patient complications. Incorporating noninvasive techniques may supplement existing methods through improved understanding of rejection causes, hepatic spatial architecture, and the role of idiopathic fibroinflammatory regions. These techniques may also aid in quantification and help integrate emerging -omics analyses with current assessments. Alternatively, emerging noninvasive methods show potential to detect and distinguish between different types of rejection while minimizing risk of adverse advents. Although biomarkers have yet to replace biopsy, preliminary studies suggest that several classes of analytes may be used to detect rejection with greater sensitivity and in earlier stages than traditional methods, possibly when coupled with artificial intelligence. Here, we provide an overview of the latest efforts in optimizing the diagnosis of rejection in liver transplantation.

Immunotherapy in liver transplantation for hepatocellular carcinoma: Pros and cons

Liver transplantation (LT) has emerged as a curative strategy for hepatocellular carcinoma (HCC), but contributes to a higher predisposition to HCC recurrence in the immunosuppression context, especially for tumors beyond the Milan criteria. Although immunotherapy has dramatically improved survival for immunocompetent patients and has become the standard of care for a variety of tumors, including HCC, it is mainly used outside the scope of organ transplantation owing to potentially fatal allograft rejection. Nevertheless, accumulative evidence has expanded the therapeutic paradigms of immunotherapy for HCC, from downstaging or bridging management in the pretransplant setting to the salvage or adjuvant strategy in the posttransplant setting. Generally, immunotherapy mainly includes immune checkpoint inhibitors (ICIs), adoptive cell transfer (ACT) and vaccine therapy. ICIs, followed by ACT, have been most investigated in LT, with some promising results. Because of the complex tumor microenvironment and immunoreactivity when immunosuppressants are combined with immunotherapy, it is difficult to reach formulations for immunosuppressant adjustment and the optimal selection of immunotherapy as well as patients. In addition, the absence of effective biomarkers for identifying rejection and tumor response is still an unresolved barrier to successful clinical immunotherapy applications for LT. In this review, we comprehensively summarize the available evidence of immunotherapy used in LT that is specific to HCC. Moreover, we discuss clinically concerning issues regarding the concurrent goals of graft protection and antitumor response.

The Human Immune Response to Cadaveric and Living Donor Liver Allografts

The liver is an important contributor to the human immune system and it plays a pivotal role in the creation of both immunoreactive and tolerogenic conditions. Liver transplantation provides the best chance of survival for both children and adults with liver failure or cancer. With current demand exceeding the number of transplantable livers from donors following brain death, improved knowledge, technical advances and the desire to prevent avoidable deaths has led to the transplantation of organs from living, ABO incompatible (ABOi), cardiac death donors and machine based organ preservation with acceptable results. The liver graft is the most well-tolerated, from an immunological perspective, of all solid organ transplants. Evidence suggests successful cessation of immunosuppression is possible in ~20–40% of liver transplant recipients without immune mediated graft injury, a state known as “operational tolerance.” An immunosuppression free future following liver transplantation is an ambitious but perhaps not unachievable goal. The initial immune response following transplantation is a sterile inflammatory process mediated by the innate system and the mechanisms relate to the preservation-reperfusion process. The severity of this injury is influenced by graft factors and can have significant consequences. There are minimal experimental studies that delineate the differences in the adaptive immune response to the various forms of liver allograft. Apart from ABOi transplants, antibody mediated hyperacute rejection is rare following liver transplant. T-cell mediated rejection is common following liver transplantation and its incidence does not differ between living or deceased donor grafts. Transplantation in the first year of life results in a higher rate of operational tolerance, possibly due to a bias toward Th2 cytokines (IL4, IL10) during this period. This review further describes the current understanding of the immunological response toward liver allografts and highlight the areas of this topic yet to be fully understood.

Clinicopathological features and outcomes of parenchymal rejection in liver transplant biopsies

AIMS

The aim of this study was to perform a comprehensive retrospective analysis of liver transplant biopsies with parenchymal rejection (PR) at our institution, including histological features, laboratory values and follow-up biopsies, and to compare PR with portal-based acute cellular rejection (ACR).

METHODS AND RESULTS

Biopsies from 173 patients were evaluated (retrospective database search 1990-2017), including 49 isolated PR, 35 PR with portal ACR (PR/ACR), 34 mild ACR and 52 moderate ACR cases. The rise and fall of serum liver enzymes was calculated as a measure of acute liver injury and response to immunotherapy, respectively. Isolated PR was associated with delayed-onset acute rejection (P < 0.001), as well as younger age (P = 0.004), and showed a similar rise in liver enzymes to mild ACR. PR/ACR and moderate ACR showed the highest elevations in transaminases (P < 0.05). Isolated PR on an initial biopsy was associated with recurrent episodes of PR (P = 0.01), chronic ductopaenic rejection (P = 0.002) and chronic vascular rejection (P = 0.017). Immunohistochemistry for C4d was performed, and strong C4d staining of venules was only detected in one severe isolated PR case (one of three, 33%) and one moderate ACR case (one of 20, 5%).

CONCLUSIONS

Isolated PR represents a form of late acute rejection with distinct clinical and histological features. There is value in reporting PR in liver transplant biopsies to identify patients at higher risk of developing recurrent PR and chronic rejection. Standardisation of terminology and histological criteria of PR can help in uniform reporting and ensure appropriate management.

Comparison of Patients With and Without Anterior Sector Venous Drainage in Right Lobe Liver Transplantation From Live Donors in Terms of Complications, Rejections, and Graft Survival: Single-Center Experience

AIM

The issue of performing an anastomosis of the anterior sector veins to the vena cava in living donor liver transplantation is still controversial. We aimed to research whether there was any difference in terms of complications, rejections, and graft survival between patients with and without anterior sector venous drainage to the vena cava.

PATIENTS AND METHODS

Patients were retrospectively investigated for demographic data and ratio of graft needed to available graft weight. Donors had volumetric calculations and middle hepatic vein anterior sector drainage documented in detail.

RESULTS

Seventy-three donors with middle hepatic vein drainage were included. Thirty-five had anterior sector venous drainage performed and 38 patients did not have drainage procedures performed. The incidence of general complications was higher in the group without anterior sector drainage (78.3% and P = .002). Biloma linked to bile leaks were observed in 8 patients without drainage (72.8%) and 3 patients with drainage (27.2%). Late acute rejection occurring during follow up after transplantation was identified in 28 patients (11.6%). Of these, 1 (14.3%) had anterior sector drainage and 6 (85.7%) were in the patient group without drainage (P = .067).

CONCLUSION

As a result of this study, for patients with grafts at the volume limit (graft weight to receiver weight ratio <0.8) and with congestion observed in the anterior sector after liver implantation and for patients with outflow problems identified on Doppler ultrasonography, anterior sector veins >5 mm should definitely be drained into the vena cava. Hence, both complication and rejection rates will reduce, and we can lengthen the graft, and thus patient, survival.

CT of acute rejection after liver transplantation: a matched case-control study

PURPOSE

This study was conducted in order to investigate computed tomography (CT) findings associated with acute cellular rejection (ACR) following liver transplantation (LT) and their relevance to clinical outcomes.

MATERIALS AND METHODS

We analyzed 120 patients with newly diagnosed ACR following LT for various liver diseases and 119 controls matched for age, sex, type of liver graft, and date of CT exam following LT. Two radiologists analyzed the images for morphological characteristics of the graft, morphological change in the major draining vein, graft enhancement in the portal venous phase, graft attenuation on noncontrast CT, and periportal halo. Univariate analysis was used to determine the association between radiological findings and ACR. Clinical outcomes, including treatment response and graft survival, were compared between patients with and without associated radiological findings.

RESULTS

Morphological characteristics of the graft (i.e., globular swelling), morphological change in the major draining vein (i.e., nonanastomotic luminal narrowing), and heterogeneous enhancement were significantly associated with ACR (all p < 0.001). On univariate analysis, the severity of morphological characteristics of the grafts (mild/severe: odds ratio [OR], 19.98/32.24) and morphological change in the major draining vein (without/with prestenotic dilatation: OR, 4.17/22.5) were significantly associated with the increased possibility of an ACR diagnosis. Clinical outcomes for treatment response and graft survival were not significantly different between patients with and without associated radiological findings.

CONCLUSIONS

Globular swelling, nonanastomotic stenosis with or without prestenotic dilatation of the major draining vein, and heterogeneous enhancement of the graft on portal venous-phase CT were significantly associated with ACR.

KEY POINTS

• Globular swelling of the graft, nonanastomotic narrowing in the major vein, and heterogeneous graft enhancement on CT were significantly associated with acute cellular rejection (ACR). • Associated CT findings were highly specific but not sensitive for differentiating ACRs from matched controls.

Antibody Drug Treatment for Steroid-Resistant Rejection After Pediatric Living Donor Liver Transplantation: A Single-Center Experience

BACKGROUND

Antibody drugs have been used to treat steroid-resistant rejection (SRR) after liver transplantation. Although anti-thymocyte globulin has been used for SRR after liver transplantation in place of muromonab-CD3 since 2011 in Japan, the effectiveness of anti-thymocyte globulin after pediatric living-donor liver transplantation (LDLT) has not yet been reported. The aim of this study was to evaluate the effectiveness of antibody drug treatment for SRR after pediatric LDLT in our single center.

METHODS

Between May 2001 and December 2013, 220 pediatric LDLTs were performed. Initial immunosuppression after LDLT included tacrolimus and methylprednisolone therapy. Acute rejection was diagnosed by use of a liver biopsy and the administration of steroid pulse treatment, and SRR was defined as acute rejection refractory to the steroid pulse treatment.

RESULTS

Acute rejection and SRR occurred in 74 (33.6%) and 16 patients (7.3%), respectively. The graft survival rates of non-SRR and SRR were 92.4% and 87.5%, respectively (P = .464). The median concentration of alanine aminotransferase before and after the administration of antibody drug was 193.5 mU/mL (range, 8-508) and 78 mU/mL (range, 9-655), respectively (P = .012). The median rejection activity index before and after the administration of antibody drugs was 5 (range, 2-9) and 1 (range, 0-9), respectively (P = .004). After antibody drug treatment, 12 patients had cytomegalovirus infections, 2 patients had Epstein-Barr virus infections, 3 patients had respiratory infections, and 1 patient had encephalitis. The cause of death in 1 patient with SRR was recurrence of infant fulminant hepatic failure.

CONCLUSIONS

Antibody drug treatment for SRR after pediatric LDLT is safe and effective.

Expression of hepatic progenitor cell markers in acute cellular rejection of liver allografts-An immunohistochemical study

BACKGROUND

Hepatic progenitor cells (HPC) are induced following liver injury to facilitate regeneration. Acute cellular rejection (ACR) is a common complication after liver transplantation as a result of immune-mediated liver injury. In this study, we characterized HPC phenotype in liver allograft biopsy with ACR. We also explored the correlation between expression HPC immunophenotype and clinicopathological parameters.

METHODS

Forty-four liver allograft biopsies performed between 2008 and 2016 in a single center with histologically proven ACR were examined for immunohistochemical expression of HPC markers CK19 and Sox9. The number of positive-staining cells was assessed and correlated with clinicopathological features by statistical analysis.

RESULTS

HPC phenotype expression as denoted by CK19 and Sox9 staining was detected in the liver tissue with ACR. The numbers of CK19+ and Sox9+ cells were positively correlated. A larger number of CK19+ cells were associated with higher serum aspartate aminotransferase (AST) level at biopsy. By histological rejection score, a larger number of Sox9+ cells were associated with a higher score of bile duct damage.

CONCLUSION

Expression HPC markers were correlated with clinical and histological parameters in ACR. Expression of each individual marker may be more tightly associated with a particular component of the ACR process.

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.

Functional Immune Anatomy of the Liver-As an Allograft

The liver is an immunoregulatory organ in which a tolerogenic microenvironment mitigates the relative "strength" of local immune responses. Paradoxically, necro-inflammatory diseases create the need for most liver transplants. Treatment of hepatitis B virus, hepatitis C virus, and acute T cell-mediated rejection have redirected focus on long-term allograft structural integrity. Understanding of insults should enable decades of morbidity-free survival after liver replacement because of these tolerogenic properties. Studies of long-term survivors show low-grade chronic inflammatory, fibrotic, and microvascular lesions, likely related to some combination of environment insults (i.e. abnormal physiology), donor-specific antibodies, and T cell-mediated immunity. The resultant conundrum is familiar in transplantation: adequate immunosuppression produces chronic toxicities, while lightened immunosuppression leads to sensitization, immunological injury, and structural deterioration. The "balance" is more favorable for liver than other solid organ allografts. This occurs because of unique hepatic immune physiology and provides unintended benefits for allografts by modulating various afferent and efferent limbs of allogenic immune responses. This review is intended to provide a better understanding of liver immune microanatomy and physiology and thereby (a) the potential structural consequences of low-level, including allo-antibody-mediated injury; and (b) how liver allografts modulate immune reactions. Special attention is given to the microvasculature and hepatic mononuclear phagocytic system.

Efficacy of rabbit anti-thymocyte globulin for steroid-resistant acute rejection after liver transplantation

Acute cellular rejection after liver transplantation (LT) can be treated with steroid pulse therapy, but there is no ideal treatment for steroid-resistant acute rejection (SRAR). We aimed to determine the feasibility and potential complications of rabbit anti-thymocyte globulin (rATG) application to treat SRAR in liver transplant recipients. We retrospectively reviewed medical records of 429 recipients who underwent LT at Severance Hospital between January 2010 and March 2015. We compared clinical features and graft survival between patients with steroid-sensitive acute rejection (SSAR; n = 23) and SRAR (n = 11). We also analyzed complications and changes in laboratory findings after 2.5 mg/kg rATG treatment in patients with SRAR for 6 to 10 days. There were no significant differences in gender, age, model for end-stage liver disease score, Child-Turcotte-Pugh score, or original liver diseases between patients with SSAR and SRAR, although deceased donors were more frequently associated with the SRAR group (P = 0.004). All SRAR patients responded positively to rATG treatment; after treatment, the patients' median AST levels decreased from 138 to 63 IU/L, and their median ALT levels dropped from 327 to 70 IU/L 1 day after rATG treatment (P = 0.022 and 0.017, respectively). Median aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin levels significantly decreased 1 month post-treatment (P = 0.038, 0.004, and 0.041, respectively). Median survival after LT was 23 months, and median survival after rATG was 22 months in patients with SRAR. Adverse effects included hepatitis C virus (HCV) reactivation, fungemia, and cytomegalovirus (CMV) infection. Nine SRAR patients survived with healthy liver function, 1 died from a traffic accident during follow-up, and 1 died from graft-versus-host disease and fungemia. Administration of rATG is an effective therapeutic option for SRAR with acceptable complications in liver transplant recipients. However, the occurrence of HCV reactivation and CMV infection in LT patients should be monitored after rATG treatment in these patients.

Transplantation With Livers From Deceased Donors Older Than 75 Years

BACKGROUND

The availability of donor organs limits the number of patients in need who are offered liver transplantation. Measures to expand the donor pool are crucial to prevent on-list mortality. The aim of this study was to evaluate the use of livers from deceased donors who were older than 75 years.

METHODS

Fifty-four patients who received a first liver transplant (D75 group) from 2001 to 2011 were included. Donor and recipient data were collected from the Nordic Liver Transplant Registry and medical records. The outcome was compared with a control group of 54 patients who received a liver graft from donors aged 20 to 49 years (D20-49 group). Median donor age was 77 years (range, 75-86 years) in the D75 group and 41 years (range, 20-49 years) in the D20-49 group. Median recipient age was 59 years (range, 31-73 years) in the D75 group and 58 years (range, 31-74 years) in the D20-49 group.

RESULTS

The 1-, 3-, and 5-year patient/graft survival values were 87/87%, 81/81%, and 71/67% for the D75 group and 88/87%, 75/73%, and 75/73% for the D20-49 group, respectively. Patient (P = 0.89) and graft (P = 0.79) survival did not differ between groups. The frequency of biliary complications was higher in the D75 group (29.6/13%, P = 0.03).

CONCLUSIONS

Selected livers from donors over age 75 years should not be excluded based on age, which does not compromise patient or graft survival despite a higher frequency of biliary complications.

Incidence of Late Acute Rejection in Living Donor Liver Transplant Patients, Risk Factors, and the Role of Immunosuppressive Drugs

INTRODUCTION

Late acute rejection (LAR) is a clinical manifestation that occurs 6 months after liver transplantation, shows histopathologic features different from those of acute rejection, and is the cause of a high prevalence of morbidity and mortality.

METHODS

In this study, hospital records of 211 living donor liver transplantation (LDLT) patients who underwent surgery in our clinic between June 2000 and February 2014 were reviewed retrospectively. The patients were ≥ 18 years old and were followed for ≥ 6 months.

RESULTS

Of the 211 patients, 21 (9.9%; 16 males, 5 females) developed LAR. The mean age of the patients was 46 years (range, 33-58). The mean follow-up period was 61.2 months (range, 6-152) and the median time to development of LAR was 26.4 months (range, 7-77). In our study, patients who received cyclosporine and mycophenolate mofetil (MMF) treatment developed more LAR than did patients who received tacrolimus and MMF therapy (P = .05). In addition, the incidence of LAR in patients who underwent LDLT was significantly greater in the ABO-matched groups than in the ABO identical group (P = .028).

CONCLUSIONS

Development of LAR and serious complications related to it can be avoided if liver transplant recipients are followed regularly and closely in outpatient clinics after transplantation.

Histological and Clinicopathological Evaluation of Liver Allograft Biopsy: An Initial Experience of Fifty Six Biopsies

INTRODUCTION

Liver biopsy is gold standard for diagnosis of allograft dysfunction.

AIM

The aim of study was to evaluate liver allograft biopsies performed for graft dysfunction, study the pattern of injury and intensity, and timeline of occurrence of graft dysfunction.

MATERIALS AND METHODS

Retrospective study was carried out of 56 liver allograft biopsies and their histological findings with clinical presentation were correlated. Totally 56 needle liver allograft biopsies from January 1210 to July 2014, obtained from 35 patients were studied for histological and clinicopathological evaluation.

RESULTS

The mean age was 53.2±5.48 years. The most common original disease was alcoholic cirrhosis. The most common histological lesion was acute cellular rejection (ACR) in 31 (55.36%) biopsies followed by preservation-reperfusion injury (PRI) in 10 (17.86%) biopsies and drug toxicity in 8 (14.29%) biopsies. Chronic rejection was reported in 2 (3.57%) and recurrence of HCV in 3 (5.36%). Ischemic coagulative necrosis and acute cholangitis were seen in 1 (1.79 %) case each.

CONCLUSION

Alcoholic cirrhosis was the most common etiology for end stage liver disease. ACR and PRI were the major complications in liver allograft biopsies at our centre.

Clinical factors affecting rejection rates in liver transplantation

BACKGROUND

With improvements in survival, liver transplant recipients now suffer more morbidity from long-term immunosuppression. Considerations were given to develop individualized immunosuppression based on their risk of rejection.

METHOD

We retrospectively analyzed the data of 788 liver transplants performed during the period from October 1991 to December 2011 to study the relationship between acute cellular rejection (ACR) and various clinical factors.

RESULTS

Multivariate analysis showed that older age (P=0.04, OR=0.982), chronic hepatitis B virus infection (P=0.005, OR= 0.574), living donor liver transplantation (P=0.02, OR=0.648) and use of interleukin-2 receptor antagonist on induction (P<0.001, OR=0.401) were associated with fewer ACRs. Patients with fulminant liver failure (P=0.004, OR=4.05) were more likely to develop moderate to severe grade ACR.

CONCLUSIONS

Liver transplant recipients with older age, chronic hepatitis B virus infection, living donor liver transplantation and use of interleukin-2 receptor antagonist on induction have fewer ACR. Patients transplanted for fulminant liver failure are at higher risk of moderate to severe grade ACR. These results provide theoretical framework for developing individualized immunosuppression.

A comparison of outcomes between OKT3 and antithymocyte globulin for treatment of steroid-resistant rejection in hepatitis C liver transplant recipients

BACKGROUND

The treatment of steroid-resistant rejection (SRR) is associated with severe recurrent hepatitis C virus (HCV) infection after liver transplantation (LTx). After OKT3 was recently withdrawn from the market, thymoglobulin (TG) became the principal treatment for SRR.

METHODS

A retrospective analysis of 32 HCV patients who were treated for SRR with OKT3 (n=15) or TG (n=17) using yearly protocol liver biopsies. Mean follow-up was 4.3 years (OKT3) and 3.2 years (TG). We compared both groups for patient survival, graft loss, and severity of HCV recurrence, manifested as the mean stage of fibrosis (MSF).

RESULTS

Patient survival at 1, 2, and 5 years after LTx was 80%, 73%, and 67% in the OKT3 group and 82%, 77%, and 64% in the TG group, respectively. At 2 years after LTx, the graft losses were 3 versus 4 in the OKT3 and TG groups, respectively. At years 1 and 2, the MSF in the OKT3 group was 1.9 and 2.3 versus 2.4 and 2.8 in the TG group, respectively. None of the differences between both groups was statistically significant.

CONCLUSION

There was no significant difference in patient survival, graft loss, or severity of recurrent HCV, measured as MSF, between both groups.

Late acute liver allograft rejection; a study of its natural history and graft survival in the current era

BACKGROUND

Late acute rejection (LAR) after liver transplantation is often associated with poor clinical outcomes. We reviewed our experience of managing LAR in the current era to determine its natural history.

METHODS

A database of 970 consecutive adult liver transplants was reviewed retrospectively. LAR was defined as histologically proven acute cellular rejection occurring more than 90 days after transplantation.

RESULTS

The incidence of LAR was 11%, with a mean time of 565 days (median, 311 days; range, 90-2922 days) after transplantation. The highest rates for LAR were in seronegative hepatitis (17%), primary biliary cirrhosis (16%), and primary sclerosing cholangitis (13%) with an odds ratio of 2.3, 2.1, and 1.8, respectively. Logistic regression showed that younger recipients, primary biliary cirrhosis, and previous graft loss were independent predictors of LAR (P<0.001). Mean trough whole blood tacrolimus levels were at their lowest levels 1 week before the diagnosis of rejection (5.5 ng/mL; SD, 2.6) compared with levels of 7.7 ng/mL 4 weeks before rejection, showing a clear temporal relation. Graft survival was worse in those with LAR (P<0.01), whereas the best graft survival was among early acute rejection cases (85% 10-year survival; P<0.01). Poor response to treatment correlated with the development of ductopenic rejection (r=0.3; P<0.01). Approximately half with early ductopenic rejection eventually died (n=15).

CONCLUSION

LAR continues to provide a risk to patient and graft survival: understanding risk factors may allow an improvement in monitoring and early intervention and so prevent early graft loss.

Biliary epithelial senescence and plasticity in acute cellular rejection

Biliary epithelial cells (BEC) are important targets in some liver diseases, including acute allograft rejection. Although some injured BEC die, many can survive in function compromised states of senescence or phenotypic de-differentiation. This study was performed to examine changes in the phenotype of BEC during acute liver allograft rejection and the mechanism driving these changes. Liver allograft sections showed a positive correlation (p < 0.0013) between increasing T cell mediated acute rejection and the number of BEC expressing the senescence marker p21(WAF1/Cip) or the mesenchymal marker S100A4. This was modeled in vitro by examination of primary or immortalized BEC after acute oxidative stress. During the first 48 h, the expression of p21(WAF1/Cip) was increased transiently before returning to baseline. After this time BEC showed increased expression of mesenchymal proteins with a decrease in epithelial markers. Analysis of TGF-β expression at mRNA and protein levels also showed a rapid increase in TGF-β2 (p < 0.006) following oxidative stress. The epithelial de-differentiation observed in vitro was abrogated by pharmacological blockade of the ALK-5 component of the TGF-β receptor. These data suggest that stress induced production of TGF-β2 by BEC can modify liver allograft function by enhancing the de-differentiation of local epithelial cells.

Hyperacute rejection in the xenogenic transplanted rat liver is triggered by the complement system only in the presence of leukocytes and free radical species

BACKGROUND

Reactive oxygen species (ROS) and nitric oxide species (NOS) are pivotal after ischemia-reperfusion. However, the role of different cells on the formation of free radical species after xenotransplantation remains elusive. We hypothesized that ROS and NOS formed during hyperacute rejection are dependent on leukocytes, erythrocytes, activated thrombocytes, and Kupffer cells (KCs). To address this issue, we developed a model of xenoperfused rat liver and assessed the relationship between free radical production and graft dysfunction.

METHODS

Livers from Sprague-Dawley rats were isolated, flushed with cold Ringer solution, and perfused at physically flow rates for 120 min after 1 h of ischemia. The control group was perfused with rat whole blood (n = 9). In the study groups, the livers were perfused with human whole blood, human plasma with erythrocytes, and plasma with erythrocytes and isolated thrombocytes (n = 9/group). In an additional group, gadolinium chloride (GdCl3), a selective Kupffer cell (KC) toxic agent, was applied. Liver damage, hyperacute rejection, and the depletion of KCs were monitored histologically. Liver damage and function were determined by means of liver enzymes, portal pressure, and bile production. Malondialdehyde (MDA), nitric oxide formation, and peroxynitrite concentration, as well as total glutathione (tGSH) level, were measured as indicators for free radical formation and anti-oxidative status.

RESULTS

Significant differences in the MDA, NO, peroxynitrite levels, and GSH levels after reperfusion with various cell populations were observed. Markedly high ROS/RNS production was evident in the KCs and the xenogeneic whole-blood group. The oxidative stress was mainly caused by leukocytes and to lower extent by KCs, but only in combination with leukocytes. Neither erythrocytes, thrombocytes, nor hepatocytes had an effect on the release of ROS and RNS, as we could not observe significant differences in the MDA, peroxynitrite, and NO levels in these groups compared with control. Tissue injury and hyperacute rejection were more evident in the KC and whole-blood livers. No sign of damage was observed for the control, erythrocyte, and thrombocyte group. Removal of leukocytes from the perfusate by filtration had a major protective effect on the liver function and the grade of hyperacute rejection, whereas KC depletion reduced the ROS production, but did not have an impact on the hyperacute rejection and liver damage. In all xenogeneic perfused groups, the activation of the complement was histologically observed by positive C3c and C9b. Neither KC depletion nor the removal of leukocytes or thrombocytes from the perfusate had an effect on the activation of the complement system. Damage of the rat liver by the complement system was only observed in association with leukocytes.

CONCLUSION

Our data revealed that various cell populations contribute to the formation of free radicals in our model. The production of free radicals was mainly linked to leukocytes and to a minor extent to KCs, but only in combination with leukocytes. Free radicals critically contribute to injury, rejection, and dysfunction of the xenotransplanted liver. Furthermore, hyperacute rejection in the xenogeneic perfused liver is triggered by the complement system only in the presence of leukocytes and free radical formation.

Importance of liver biopsy findings in immunosuppression management: biopsy monitoring and working criteria for patients with operational tolerance

Obstacles to morbidity-free long-term survival after liver transplantation (LT) include complications of immunosuppression (IS), recurrence of the original disease and malignancies, and unexplained chronic hepatitis and graft fibrosis. Many programs attempt to minimize chronic exposure to IS by reducing dosages and stopping steroids. A few programs have successfully weaned a highly select group of recipients from all IS without apparent adverse consequences, but long-term follow-up is limited. Patients subjected to adjustments in IS are usually followed by serial liver chemistry tests, which are relatively insensitive methods for detecting allograft damage. Protocol biopsy has largely been abandoned for hepatitis C virus-negative recipients, at least in part because of the inability to integrate routine histopathological findings into a rational clinical management algorithm. Recognizing a need to more precisely categorize and determine the clinical significance of findings in long-term biopsy samples, the Banff Working Group on Liver Allograft Pathology has reviewed the literature, pooled the experience of its members, and proposed working definitions for biopsy changes that (1) are conducive to lowering IS and are compatible with operational tolerance (OT) and (2) raise concern for closer follow-up and perhaps increased IS during or after IS weaning. The establishment of guidelines should help us to standardize analyses of the effects of various treatments and/or weaning protocols and more rigorously categorize patients who are assumed to show OT. Long-term follow-up using standardized criteria will help us to determine the consequences of lowering IS and to define and determine the incidence and robustness of OT in liver allografts.

Recipient interleukin-28B Rs12979860 C/T polymorphism and acute cellular rejection after liver transplantation: role of the calcineurin inhibitor used

BACKGROUND

Interleukin-28 (IL-28B) rs12979860 C/T polymorphism is known to predict the outcome of antiviral therapy in hepatitis C. In addition to its interferon-like and antiviral functions, IL-28B possesses the ability to modulate CD8 T cells function. This study aimed to investigate whether recipient IL-28B polymorphism may have a role in predicting the occurrence of acute cellular rejection (ACR) after liver transplantation (LT).

METHODS

Two hundred fifty-one consecutive LT recipients were enrolled. All the patients underwent per protocol liver biopsies at 1, 3, and 12 months after LT. ACR episodes in the first post-LT year were recorded and graded according to the Banff score.

RESULTS

At least one moderate to severe (Banff score ≥ 5) ACR episode was reported in 75 patients (29.9%). ACR was associated with IL-28B polymorphism: C/C=21/102 (20.6%), C/T=43/126 (34.1%), and T/T=11/23 (47.8%) (P=0.003). At logistic regression analysis, IL-28B polymorphism was found to be a predictor of ACR (P=0.012) together with cytomegalovirus reactivation (P=0.023). The association between IL-28B polymorphism and ACR occurrence was evident in tacrolimus but not in cyclosporine-treated patients. ACR episodes occurred more frequently from hepatitis C virus (HCV) negatives carrying the IL-28B C/C genotype (17.8%) to HCV negatives carrying at least one T allele or HCV positives carrying at least one C allele (33.3%) to HCV positives carrying the T/T genotype (50.0%, P=0.002).

CONCLUSIONS

HCV etiology in association with the carriage of IL-28B T/T genotype predicted the highest frequency of ACR. Recipient's IL-28B genotyping could be a useful tool in individualizing immunosuppressive therapy according to the risk of ACR occurrence.

The significance of plasma cell infiltrate in acute cellular rejection of liver allografts

Acute cellular rejections of higher grades of histologic severity are associated with increased risk of graft failure and death after liver transplantation. Plasma cell-rich infiltrates are associated with adverse clinical outcomes in acute renal allograft rejection and in liver allografts without rejection, but there are limited data on plasma cell-rich infiltrates in acute liver allograft rejection. In this study, 59 biopsies of acute liver allograft rejection were confirmed histologically and clinically, independently graded, and the percentage of plasma cells in portal inflammatory infiltrate was objectively assessed using a standardized protocol. Plasma cell infiltrates were observed in 32 (54%) of the specimens, the mean percentage of plasma cells in the infiltrates being 2.97%. Infiltrates with any plasma cells were significantly more common in groups with higher histologic severity of rejection (75% and 100% versus 31% and 48%, P = .006). The mean percentage of plasma cells in the portal infiltrate was also significantly higher in groups with higher histologic severity of rejection (4.95% and 17.82% versus 0.37 and 0.82%, P = .0002). All the biopsies with more than 30% plasma cells in the infiltrate were found to have severe rejection, whereas all with more than 10% plasma cells had either moderate or severe rejection. The association of plasma cell-rich infiltrates with histologic severity of rejection suggests that plasma cell-rich infiltrates could potentially be useful as a marker of severe rejection.

Anti-thymocyte globulin for the treatment of acute cellular rejection following liver transplantation

INTRODUCTION

Acute cellular rejection (ACR) post-liver transplantation (LT) can usually be reversed with pulse dose steroids. Anti-thymocyte globulin (ATG) is used to treat steroid-resistant rejection (SRR).

PATIENTS AND METHODS

We report 15 male and five female LT recipients with a median age of 48.3 (range 14.3-71.7) years, who received ATG for biopsy-proven steroid-resistant rejection (n =13), severe rejection (6), and severe rejection/recurrent autoimmune hepatitis (n = 1) median 42 (range 6-2,456) days following LT.

RESULTS

Underlying liver diseases included HCV (n = 7), alcoholic cirrhosis (n = 3), NASH (n = 2), HBV (n = 2), autoimmune hepatitis (n =1), PSC (n = 1), miscellaneous (n = 4) including three re LTs. All patients responded to treatment (median AST declined from 172 to 34U/l, median total bilirubin from 9.1 to 1.3 mg/dl; p < 0.001). Three patients developed recurrent ACR, and none chronic rejection. All HCV patients developed recurrence with significant rises in HCV RNA levels. Infections included pneumonia, sepsis, intraabdominal infection, chronic diarrhea, wound infection, EBV, and CMV disease. After a median follow-up of 65.5 (range 4.3-101.7) months post-ATG and median 67.7 (range 9.3-306.3) months post-LT, 17 patients are alive, two died from sepsis/multi-organ failure and one from HCV recurrence.

CONCLUSION

ATG effectively reversed severe and SSR; HCV recurrence and infections remain significant complications.

Adding value to liver (and allograft) biopsy evaluation using a combination of multiplex quantum dot immunostaining, high-resolution whole-slide digital imaging, and automated image analysis

Various technologies including nucleic acid, protein, and metabolic array analyses of blood, liver tissue, and bile are emerging as powerful tools in the study of hepatic pathophysiology. The entire lexicon of liver disease, however, has been written using classical hematoxylin-eosin staining and light microscopic examination. The authors' goal is to develop new tools to enhance histopathologic examination of liver tissue that would enrich the information gained from liver biopsy analysis, enable quantitative analysis, and bridge the gap between various "-omics" tools and interpretation of routine liver biopsy results. This article describes the progress achieved during the past 2 years in developing multiplex quantum dot (nanoparticle) staining and combining it with high-resolution whole-slide imaging using a slide scanner equipped with filters to capture 9 distinct fluorescent signals for multiple antigens. The authors first focused on precise characterization of leukocyte subsets, but soon realized that the data generated were beyond the practical limits that could be properly evaluated, analyzed, and interpreted visually by a pathologist. Therefore, the authors collaborated with the open source FARSIGHT image analysis project (http://www.farsight-toolkit.org). FARSIGHT's goal is to develop and disseminate the next-generation toolkit of automated image analysis methods to enable quantification of molecular biomarkers on a cell-by-cell basis from multiparameter images. The resulting data can be used for histocytometric studies of the complex and dynamic tissue microenvironments that are of biomedical interest. The authors envisage that these tools will eventually be incorporated into the routine practice of surgical pathology and precipitate a revolution in the specialty.

Vitamin D and the risk of acute allograft rejection following human liver transplantation

BACKGROUND

Vitamin D may act as an immune modulator in experimental and human organ transplantation, but these data are yet to be confirmed in human liver transplantation (LT).

AIM

This study aimed to assess the relationship between acute liver allograft cellular rejection (ACR) and pretransplant serum vitamin D concentration or post-transplant vitamin D supplementation.

METHOD

We studied 133 LT recipients who underwent two per protocol allograft biopsies in the early post-operative period, plus on-demand biopsies as clinically indicated. ACR estimate was given according to the Banff scheme in biopsies obtained along two follow-up periods: (a) from the transplant operation to the end of the second month (0-2 months); (b) and from the third month to the end of the eighth month (3-8 months) post-LT.

RESULTS

The median pretransplant serum 25-hydroxyvitamin D concentration was 12.5 ng/ml; 40 patients had concentrations < or =12.5 ng/ml, of whom six had < or =5.0 ng/ml. Seventy-nine recipients received oral vitamin D(3) supplementation to treat post-transplant osteoporosis. In the 0-2 months period, moderate-to-severe rejection episodes were independently associated with cytomegalovirus reactivation (P<0.005) and progressively lower pretransplant serum 25-hydroxyvitamin D concentrations (P<0.02). Early vitamin D(3) supplementation was independently associated with a lack of ACR (P<0.05).

CONCLUSIONS

These results suggest that vitamin D may favour immune tolerance towards the liver allograft.

Liver transplantation

Liver transplantation has become a lifesaving procedure for patients who have chronic end-stage liver disease and acute liver failure. The satisfactory outcome of liver transplantation has led to insufficient supplies of deceased donor organs, particularly in East Asia. Hence, East Asian surgeons are concentrating on developing and performing living-donor liver transplantation (LDLT). This review article describes an update on the present status of liver transplantation, mainly in adults, and highlights some recent developments on indications for transplantation, patient selection, donor and recipient operation between LDLT and deceased-donor liver transplantation (DDLT), immunosuppression, and long-term management of liver transplant recipients. Currently, the same indication criteria that exist for DDLT are applied to LDLT, with technical refinements for LDLT. In highly experienced centers, LDLT for high-scoring (>30 points) Model of End-Stage Liver Disease (MELD) patients and acute-on-chronic liver-failure patients yields comparably good outcomes to DDLT, because timely liver transplantation with good-quality grafting is possible. With increasing numbers of liver transplantations and long-term survivors, specialized attention should be paid to complications that develop in the long term, such as chronic renal failure, hypertension, diabetes mellitus, dyslipidemia, obesity, bone or neurological complications, and development of de novo tumors, which are highly related to the immunosuppressive treatment.

Liver biopsy findings from healthy potential living liver donors: reasons for disqualification, silent diseases and correlation with liver injury tests

BACKGROUND/AIMS

Liver biopsies detect silent donor disease in potential living liver donors and provide material for studies of subclinical non-alcoholic fatty liver disease (NAFLD). Our primary goal was to determine the contribution of biopsy findings to potential donor evaluation. Factors contributing to pre-clinical NAFLD and correlations between liver injury tests and histopathology have been also determined.

METHODS

Patient records, laboratory tests and results of the histopathologic examination and diagnoses of 284 patients from 2001 to 2005 were retrospectively extracted from the EDIT database. Hepatic histology was correlated with liver injury tests and with general demographic characteristics in an otherwise normal healthy population.

RESULTS

A minority (n=119; 42%) of biopsies from this population of 143 males/141 females (average age=36.8years; mean BMI=26.6) were completely normal. The remainder showed steatosis (n=107; 37%), steatohepatitis (n=44; 15%), or unexplained low-grade/early stage chronic hepatitis, primary biliary cirrhosis, or nodular regenerative hyperplasia (n=16; 6%). Biopsy findings disqualified 29/56 donors. Independent risk factors for NAFLD by multivariate modeling, which differed by sex, included: BMI (p=0.0001), age (p=0.003), iron (p=0.01), and ALT (p=0.004).

CONCLUSIONS

Liver biopsies provide valuable information about otherwise undetectable liver disease in potential liver donors. Obesity, age and iron, which are influenced by sex, contribute to NAFLD pathogenesis. Blood tests other than standard liver profiles are needed to detect early NAFLD.

Seeking beyond rejection: an update on the differential diagnosis and a practical approach to liver allograft biopsy interpretation

Pathologic evaluation of liver allograft biopsies plays an integral role in the management of patients after liver transplantation. This review summarizes the clinical context and classical histology of different types of allograft rejection and also the common entities that enter the differential diagnosis of allograft rejection, and provides practical approaches to liver allograft biopsy interpretation. In addition, some of the new developments in the field of liver transplant pathology are updated. The purpose of this review is to provide guidance for pathologists interpreting liver allograft biopsies, particularly those interested in developing expertise in the field of liver transplant pathology.

Monitoring of human liver and kidney allograft tolerance: a tissue/histopathology perspective

Several factors acting together have recently enabled clinicians to seriously consider whether chronic immunosuppression is needed in all solid organ allograft recipients. This has prompted a dozen or so centers throughout the world to prospectively wean immunosuppression from conventionally treated liver allograft recipients. The goal is to lessen the impact of chronic immunosuppression and empirically identify occasional recipients who show operational tolerance, defined as gross phenotype of tolerance in the presence of an immune response and/or immune deficit that has little or no significant clinical impact. Rare operationally tolerant kidney allograft recipients have also been identified, usually by single case reports, but only a couple of prospective weaning trials in conventionally treated kidney allograft recipients have been attempted and reported. Pre- and postweaning allograft biopsy monitoring of recipients adds a critical dimension to these trials, not only for patient safety but also for determining whether events in the allografts can contribute to a mechanistic understanding of allograft acceptance. The following is based on a literature review and personal experience regarding the practical and scientific aspects of biopsy monitoring of potential or actual operationally tolerant human liver and kidney allograft recipients where the goal, intended or attained, was complete withdrawal of immunosuppression.

The prevalence and natural history of untreated isolated central perivenulitis in adult allograft livers

Central perivenulitis (CP) in the allograft liver can be associated with portal-based acute cellular rejection and autoimmune hepatitis or can occur in isolation (isolated CP). Although several studies have demonstrated the significance of CP, the prevalence and natural history of untreated isolated CP have not been well studied. We examined 100 adult allograft liver recipients who had long-term follow-up, had routine protocol biopsies, and received no treatment for isolated CP. Isolated CP was identified in 28 (28%) patients. It occurred late at a mean of 658 days. Interestingly, patients with late isolated CP (defined as >3 months posttransplant) usually manifested only mildly to modestly elevated liver function tests. However, late isolated CP was associated with prior and subsequent allograft complications. Nearly all (94%) cases of late isolated CP occurred in patients who had early episodes of CP and/or acute cellular rejection. Of 13 patients who developed adverse outcomes in their allografts (zone 3 fibrosis in 10, de novo autoimmune hepatitis in 3, and ductopenia in 3), all experienced episodes of prior CP, and 12 (92%) had late CP; 1 patient required retransplant for chronic rejection, but all were alive within the last year. In summary, "transplant-associated" isolated CP occurs in 28% of adult patients, early CP is predictive of late CP, and late CP (often present as isolated CP) is associated with long-term liver injury in some patients.

Hepatic parenchymal changes and histologic eosinophilia as predictors of subsequent acute liver allograft rejection

During the first episode of acute cellular rejection (ACR) after liver transplantation, centrilobular changes in liver biopsy specimens may be possible indicators of subsequent episodes of ACR, early chronic rejection, or acute graft loss. The purpose of this study was to identify differences between the histopathological findings in liver biopsy specimens obtained during the first rejection episode in patients who subsequently developed further episodes of ACR and those who did not. The histopathological findings in 22 patients who had a single episode of acute rejection (group 1) were compared with those in 23 patients who had multiple episodes of acute rejection (group 2). Only the first liver biopsy samples of the latter group were taken into consideration. We assessed the predictive value of centrilobular necrosis, central vein endothelialitis, pericentral inflammation, hepatocellular ballooning, cholestasis, hepatocellular apoptosis, lobular inflammation, the degree of portal eosinophilia, and characteristic portal tract features in poor responders to antirejection treatment. The time to the first episode of ACR and the rejection activity index were similar in patients in both groups. Hepatocellular apoptosis, hepatocellular ballooning, and central vein endothelialitis were common features of both groups. The incidences of pericentral inflammation, centrilobular necrosis, and portal eosinophilia were significantly higher in patients in group 2 than in those in group 1 (P < 0.05). Patients with pericentral inflammation, centrilobular necrosis, and marked portal eosinophilia during an initial episode of acute rejection may be more likely to develop subsequent episodes of ACR.

Incremental costs of post-liver transplantation complications

BACKGROUND

Complications after liver transplantation are common and expensive. The incremental costs of adult posttransplantation liver transplantation complications and who pays for these complications (center or payor) is unknown.

STUDY DESIGN

We reviewed the medical and financial records (first 90 postoperative days) of all adult liver transplant recipients at our center between July 1, 2002, and October 30, 2005 (N = 214). The association of donor, recipient, and financial data points (total costs, reimbursements, and profits) was assessed using standard univariable analyses. The incremental costs of complications were determined with multiple linear regression models to control for the costs inherent to donor and recipient characteristics.

RESULTS

Univariate analyses demonstrated that both total hospital costs and reimbursements were substantially increased in patients with several different complications. Multiple linear regression analysis, controlling for recipient (age, gender, race, and laboratory Model for End-Stage Liver Disease [MELD]) and donor factors (donor risk index), noted that increased hospital costs and hospital reimbursements were independently associated with laboratory MELD (incremental costs of $3,368 and $2,787, respectively, per MELD point) and pneumonia ($83,718 and $68,214, respectively). A negative profit margin for the medical center was independently associated with peritonitis ($21,760). Commercial insurance was associated with no changes in total costs when compared with public insurer, but it was associated with decreased reimbursement and profit.

CONCLUSIONS

The incremental costs of complications in liver transplantation are high for both the medical center and payor, but medical center profits are not affected substantially. The payor bears the financial burden for post-liver transplantation complications.

Randomized controlled trial of total immunosuppression withdrawal in liver transplant recipients: role of ursodeoxycholic acid

BACKGROUND

Total immunosuppression withdrawal (TIW) without causing rejection has been reported in stable liver recipients. The role of ursodeoxycholic acid (UDCA) and patient characteristics that predict the success of this tolerance are unclear. There are two goals, to determine: 1) whether TIW is frequently associated with rejection; and 2) whether UDCA decreases the risk of liver disease (both rejection and recurrence) after TIW.

METHODS

Twenty-six liver recipients who had been free of rejection while on immunosuppressive agents for a minimum of 2 years were randomized to receive either (15 mg/kg) of UDCA (n=14) or identical placebo (n=12) followed by sequential withdrawal of their immunosuppressive regimen over several months. Endpoints were defined as biochemical and histological evidence of rejection, graft dysfunction without rejection, recurrence of pretransplant disease, or 6 months without immunosuppression and no rejection or dysfunction on repeat liver biopsy.

RESULTS

Rejection occurred in 6 of 14 (43%) of the UDCA group and 9 of 12 (75%) of those receiving placebo (P=0.09). Degree of rejection was mild, moderate, and severe in 73%, 20%, and 7% of patients respectively. All responded to rescue therapy and none developed chronic rejection. Nine of the remaining 11 patients (eight of the UDCA recipients and three of controls) who did not develop rejection developed graft dysfunction which responded to reintroduction of immunosuppressive agents in each case. Disease recurrence was most common in patients with underlying immune-mediated disorders of the liver. One year after withdrawal only two patients were free of immunosuppression, 80% were able to discontinue prednisone therapy (steroid free), and 50% were able to reduce their dose of cyclosporine. Age, underlying cause of liver disease, and regimen of immunosuppression were favorable predictors.

CONCLUSIONS

The results of this study suggest that TIW: 1) is frequently associated with subsequent rejection, 2) increases the risk of underlying disease recurrence, and 3) is not facilitated by UDCA use and responds properly to the reintroduction of immunosuppressive therapy.

Acute rejection in HCV-infected liver transplant recipients: The great conundrum

1. In hepatitis C virus (HCV)-infected patients, treatment of acute rejection is associated with worse outcomes (increased risk of allograft cirrhosis and mortality). 2. Whether patients with HCV are at higher risk for rejection remains controversial. 3. The mechanisms mediating acute rejection and recurrence of HCV are distinct, and as such, it should be possible to develop techniques based on these molecular differences that are diagnostically useful. 4. Liver biopsy is considered the gold-standard for diagnosing acute rejection and recurrent HCV; however, given histopathological similarities between the two conditions, discrimination can be extremely difficult. 5. At the present time, there are no reliable, noninvasive tools available to distinguish between HCV recurrence alone and acute rejection plus HCV recurrence. 6. Mild rejection per se is not associated with graft loss and treatment of rejection with steroids and OKT3 is associated with worse outcome in HCV; thus, it seems logical that we should no longer treat mild rejection.

The incidence and management of acute and chronic rejection after living donor liver transplantation

Living donor liver transplantation (LDLT) is a good alternative to cadaveric liver transplantation for end-stage liver disease. Herein we report the outcome of 132 LDLTs performed between 1999 and 2005, with special emphasis on the incidence and management of acute and chronic rejection. Among the LDLT population a first acute rejection episode (ARE) was clinically suspected in 24% and proven by liver biopsy in 11%. According to the Banff classification, 50% of AREs were grade 1, and 50%, grade 2. There was no grade 3 AREs. The first ARE occurred between 7 days and 23 months posttransplantation (mean 97 days, median 70 days). Ninety-seven percent (31/32) of the AREs occurred within the first year after transplantation and 3% (1/32) in the second year. Among the patients with ARE, 23% developed a second ARE between 4 and 11 months. A third ARE was detected in 8% of patients after month 18. All AREs responded to adjustment of immunosuppressive doses or steroid boluses. Chronic rejection (CR) was detected in 2%. In conclusion, the incidences of ARE and CR are consistent with the previously reported data. Acute and chronic rejections seem to be mild and easily manageable clinical conditions. Our results also showed a significant difference between clinically suspected and biopsy-proven ARE emphasizing the importance of indicated liver biopsies in the management of the LDLT population.

Liver biopsy interpretation for causes of late liver allograft dysfunction

Evaluation of needle biopsies and extensive clinicopathological correlation play an important role in the determination of liver allograft dysfunction occurring more than 1 year after transplantation. Interpretation of these biopsies can be quite difficult because of the high incidence of recurrent diseases that show histopathological, clinical, and serological features that overlap with each other and with rejection. Also, more than one insult can contribute to allograft injury. In an attempt to enable centers to compare and pool results, improve therapy, and better understand pathophysiological disease mechanisms, the Banff Working Group on Liver Allograft Pathology herein proposes a set of consensus criteria for the most common and problematic causes of late liver allograft dysfunction, including late-onset acute and chronic rejection, recurrent and new-onset viral and autoimmune hepatitis, biliary strictures, and recurrent primary biliary cirrhosis and primary sclerosing cholangitis. A discussion of differential diagnosis is also presented.

Does the Banff rejection activity index predict outcome in patients with early acute cellular rejection following liver transplantation?

The Banff schema incorporates a semiquantitative scoring system for grading of acute cellular rejection (ACR) of the liver allograft. The Banff rejection activity index (RAI) comprises 3 components scored from 0 to 3: venous endothelial inflammation (E); bile duct damage (B); and portal inflammation (P); the scores are combined to an overall score (the RAI). The purpose of this research was to determine the prognostic value of the Banff RAI score in predicting the response to increased immunosuppression and the long-term outcome of the graft. A retrospective study was done of patients undergoing primary liver transplantation between January 2000 and October 2004 with tacrolimus-based immunosuppression; 495 patients were included, 231 had histologically-confirmed ACR, 193 responded to 1 cycle of high-dose steroids. There was no correlation between the total RAI score and response to steroids, resistant rejection, development of chronic rejection, or graft survival. The E score was related to patient survival, a lower score being associated with a worse outcome (P = 0.048). In multivariable analysis, serum bilirubin, serum aspartate aminotransferase, and E score were significant predictors of death (P = 0.012). In univariable analysis, B score and bilirubin were significantly related to "resistant rejection" (P = 0.018 and 0.002, respectively), but only bilirubin was significant in multivariable analysis (logistic regression). In conclusion, although the Banff RAI score is a useful marker of the severity of rejection, neither the total RAI score nor any of the individual components correlated with response to steroids or graft survival.

Mycophenolate mofetil use is associated with decreased risk of late acute rejection in adult liver transplant recipients

Mycophenolate mofetil (MMF) used in a triple-drug regimen has been shown to decrease acute rejection rates, compared to a double-drug regimen. The impact of MMF on late acute rejection (LAR) episodes has not been well described. To investigate the risk of LAR (rejection > or = 6 months post-transplantation) data from the Scientific Registry of Transplant Recipients (SRTR) were used. We studied adult primary liver transplant recipients transplanted between June 1, 1995, and April 30, 2004, with hepatitis C virus (HCV) (n = 3356), hepatitis B virus (HBV) (n = 550) or a nonviral (n = 5740) primary cause of liver disease who were recorded as receiving continuous 3-(MMF + Tacro + steroids) versus 2-drug (Tacro + steroids) therapy for at least 6 months immediately post transplantation. Kaplan-Meier analysis showed significantly lower LAR rates 4 years post-transplant in 3- versus 2-drug HCV, HBV and nonviral disease patients. Multivariate regression confirmed 3- versus 2-drug therapy to be associated with a decreased risk of LAR. Late graft survival was significantly lower at 4 years post-transplant for patients with LAR 6-12 months post-transplantation versus patients with early rejection (78.0% vs. 87.0%, p < 0.001) and no rejection (88.1%, p < 0.001). Three-drug versus 2-drug therapy for a minimum of 6 months may offer a better treatment strategy to avoid the consequences and expense of LAR episodes.

Pathomorphological Features of Acute Rejection in Patients After Orthotopic Liver Transplantation: Own Experience

INTRODUCTION

Acute hepatic allograft rejection remains an important problem following liver transplantation. Liver biopsy specimens show a combination of characteristic changes, first observed by Snover as a diagnostic triad: portal inflammation, bile duct damage, and central or portal vein endothelial inflammation (endothelitis or endothelialitis). The aim of this study was to describe our histopathological assessment of liver transplants.

MATERIALS AND METHODS

In the period between September 2000 and June 2004, we evaluated 150 liver biopsy specimens from 105 liver recipients.

RESULTS

Acute rejection was diagnosed in 26.6% of liver biopsies taken from 31.4% patients who demonstrated clinical symptoms of liver damage. In 90% of cases the rejection was described as minimal or mild, and in 10% as moderate. There was no episode of severe acute rejection. Only four biopsies (10%) showed nothing but Snover triad changes. In 9 (22.5%) cases only acute rejection was diagnosed; the remaining showed in addition to acute rejection the possibility of other concomitant pathologies: viral infection in 15 cases (37.5%), biliary flow obstruction in 11 cases (28.5%), functional cholestasis in two cases (5%), and ischemic complications in three cases (7.5%).

CONCLUSIONS

Histologically confirmed acute rejection episodes were diagnosed in 14.9% liver recipients. Liver biopsy specimens, aside from Snover triad features, often showed other unspecific morphological changes. Differentiation of acute rejection from other accompanying diseases is sometimes difficult, requiring precise clinical data and pathologist experience.