Cytomegalovirus infection and donor/recipient HLA antigens: interdependent co-factors in pathogenesis of vanishing bile-duct syndrome after liver transplantation

The Effect of Genetic HLA Matching on Liver Transplantation Outcome: A Systematic Review and Meta-Analysis

Objective

We aim to investigate the effects of genetically based HLA matching on patient and graft survival, and acute and chronic rejection after liver transplantation.

Background

Liver transplantation is a common treatment for patients with end-stage liver disease. In contrast to most other solid organ transplantations, there is no conclusive evidence supporting human leukocyte antigen (HLA) matching for liver transplantations. With emerging alternatives such as transplantation of bankable (stem) cells, HLA matching becomes feasible, which may decrease the need for immunosuppressive therapy and improve transplantation outcomes.

Methods

We systematically searched the PubMed, Embase, and Cochrane databases and performed a meta-analysis investigating the effect of genetic HLA matching on liver transplantation outcomes (acute/chronic rejection, graft failure, and mortality).

Results

We included 14 studies with 2682 patients. HLA-C mismatching significantly increased the risk of acute rejection (full mismatching: risk ratio = 1.90, 95% confidence interval = 1.08 to 3.33, P = 0.03; partial mismatching: risk ratio = 1.33, 95% confidence interval = 1.07 to 1.66, P = 0.01). We did not discern any significant effect of HLA mismatching per locus on acute rejection for HLA-A, -B, -DR, and -DQ, nor on chronic rejection, graft failure, or mortality for HLA-DR, and -DQ.

Conclusions

We found evidence that genetic HLA-C matching reduces the risk of acute rejection after liver transplantation while matching for other loci does not reduce the risk of acute rejection, chronic rejection, graft failure, or mortality.

Assessment of human leukocyte antigen matching algorithm PIRCHE-II on liver transplantation outcomes

For liver transplantations, human leukocyte antigen (HLA) matching is not routinely performed because observed effects have been inconsistent. Nevertheless, long-term liver transplantation outcomes remain suboptimal. The availability of a more precise HLA-matching algorithm, Predicted Indirectly Recognizable HLA Epitopes II (PIRCHE-II), now enables robust assessment of the association between HLA matching and liver transplantation outcomes. We performed a single-center retrospective cohort study of 736 liver transplantation patients. Associations between PIRCHE-II and HLAMatchmaker scores and mortality, graft loss, acute and chronic rejection, ischemic cholangiopathy, and disease recurrence were evaluated with Cox proportional hazards models. Associations between PIRCHE-II with 1-year, 2-year, and 5-year outcomes and severity of acute rejection were assessed with logistic and linear regression analyses, respectively. Subgroup analyses were performed for autoimmune and nonautoimmune indications, and patients aged 30 years and younger, and older than 30 years. PIRCHE-II and HLAMatchmaker scores were not associated with any of the outcomes. However, patients who received transplants for autoimmune disease showed more acute rejection and graft loss, and these risks negatively associated with age. Rhesus mismatch more than doubled the risk of disease recurrence. Moreover, PIRCHE-II was inversely associated with graft loss in the subgroup of patients aged 30 years and younger with autoimmune indications. The absence of associations between PIRCHE-II and HLAMatchmaker scores and the studied outcomes refutes the need for HLA matching for liver (stem cell) transplantations for nonautoimmune disease. For autoimmune disease, the activated immune system seems to increase risks of acute rejection and graft loss. Our results may suggest the benefits of transplantations with rhesus matched but PIRCHE-II mismatched donor livers.

Management of Biliary Complications in Liver Transplant Recipients

Biliary complications are often referred to as the Achilles' heel of liver transplantation (LT). The most common of these complications include strictures, and leaks. Prompt diagnosis and management is key for preservation of the transplanted organ. Unfortunately, a number of factors can lead to delays in diagnosis and make adequate treatment a challenge. Innovations in advanced endoscopic techniques have increased non-surgical options for these complications and in many cases is the preferred approach.

Impact of human leukocyte antigen compatibility on outcomes of living donor liver transplantation: Experience from a tertiary care center

INTRODUCTION

The role of HLA compatibility in kidney, heart, and stem cell transplantation is well known, but with regard to living donor liver transplantation (LDLT), there is a different scenario. In the present study, we aim to examine the effects of donor-recipient HLA mismatches at A, B, and DR loci on various outcomes of LDLT-like graft survival, early allograft dysfunction (EAD), acute rejection, length of hospital (LOH) stay, sepsis, and cytomegalovirus (CMV) reactivation.

METHODS

This is a retrospective single center study of a cohort of adult patients who underwent first time ABO-compatible (ABOc) LDLT between January 2010 and December 2018. Transplants with incomplete records or without HLA typing data were excluded. Donor-recipient HLA-A, B, and DR mismatches were assessed in the host versus graft (HVG) direction and were correlated with various post-transplant outcomes.

RESULTS

Among 140 transplants being evaluated, approximately two third had total HLA mismatches between 2 and 3. HLA mismatches at each locus as well as cumulative HLA mismatches did not show any association with overall graft survival, EAD, acute rejection episodes, and LOH stay. However, the presence of minimum one mismatch at HLA-A and DR loci was associated with the development of CMV reactivation (P = .03) and sepsis (P = .02) post-LDLT respectively.

CONCLUSION

HLA mismatch is not associated with acute rejection, early graft dysfunction, and overall survival in LDLT. Its impact on CMV reactivation and sepsis needs further evaluation.

Biliary complications after liver transplantation: current perspectives and future strategies

Importance

Liver transplantation (LT) is a life-saving therapy for patients with end-stage liver disease and with acute liver failure, and it is associated with excellent outcomes and survival rates at 1 and 5 years. The incidence of biliary complications (BCs) after LT is reported to range from 5% to 20%, most of them occurring in the first three months, although they can occur also several years after transplantation.

Objective

The aim of this review is to summarize the available evidences on pathophysiology, risk factors, diagnosis and therapeutic management of BCs after LT.

Evidence Review

a literature review was performed of papers on this topic focusing on risk factors, classifications, diagnosis and treatment.

Findings

Principal risk factors include surgical techniques and donor's characteristics for biliary leakage and anastomotic biliary strictures and vascular alterations for non- anastomotic biliary strictures. MRCP is the gold standard both for intra- and extrahepatic BCs, while invasive cholangiography should be restricted for therapeutic uses or when MRCP is equivocal. About treatment, endoscopic techniques are the first line of treatment with success rates of 70-100%. The combined success rate of ERCP and PTBD overcome 90% of cases. Biliary leaks often resolve spontaneously, or with the positioning of a stent in ERCP for major bile leaks.

Conclusions and Relevance

BCs influence morbidity and mortality after LT, therefore further evidences are needed to identify novel possible risk factors, to understand if an immunological status that could lead to their development exists and to compare the effectiveness of innovative surgical and machine perfusion techniques.

Prevention and therapy of viral infections in patients with solid organ transplantation

Solid organ transplantation (SOT) is the best treatment option for end-stage organ disease. The number of SOT procedures has been steadily increasing worldwide during the past decades. This trend has been accompanied by the continuous incorporation of new antimicrobial drugs and by the refinement of strategies aimed at minimizing the risk of opportunistic infection. Nonetheless, viral infections, which can occur at any stage of the post-transplant period, remain a clinical challenge that negatively impacts both patient and graft outcomes. This review offers an overview of the most relevant viral infections in the SOT population, with a focus on herpesviruses (cytomegalovirus, Epstein-Barr virus, varicella-zoster virus, and herpes simplex virus 1 and 2) and polyomaviruses (human BK polyomavirus). In addition, the currently recommended prophylactic and treatment approaches are summarized, as well as the new antiviral agents in different phases of clinical development.

Post liver transplant recurrent and de novo viral infections

Survival following liver transplantation has changed dramatically owing to improvement in surgical techniques, peri-operative care and optimal immunosuppressive therapy. Post-Liver transplant (LT) de novo or recurrent viral infection continues to cause major allograft dysfunction, leading to poor graft and patient survival in untreated patients. Availability of highly effective antiviral drugs has significantly improved post-LT survival. Patients transplanted for chronic hepatitis B infection should receive life-long nucleos(t)ide analogues, with or without HBIg for effective viral control. Patients with chronic hepatitis C should be commenced on directly acting antiviral (DAA) drugs prior to transplantation. DAA therapy for post-LT recurrent hepatitis C infection is associated with close to 100% sustained virological response (SVR), irrespective of genotype. De novo chronic Hepatitis E infection is an increasingly recognised cause of allograft dysfunction in LT recipients. Untreated chronic HEV infection of the graft may lead to liver fibrosis and allograft failure. CMV and EBV can reactivate leading to systemic illness following liver transplantation. With COVID-19 pandemic, post-transplant patients are at risk of SARS-Co-V2 infection. Majority of the LT recipients require hospitalization, and the mortality in this population is around 20%. Early recognition of allograft dysfunction and identification of viral aetiology is essential in the management of post-LT de novo or recurrent infections. Optimising immunosuppression is an important step in reducing the severity of allograft damage in the treatment of post-transplant viral infections. Viral clearance or control can be achieved by early initiation of high potency antiviral therapy.

Efficacy and Safety of Chemotherapy Following Anti-PD-1 Antibody Therapy for Gastric Cancer: A Case of Sclerosing Cholangitis

Immunotherapy targeting programmed cell death-1 (PD-1) signaling is becoming the standard of care for advanced gastric cancer. We herein report a patient with gastric adenocarcinoma with peritoneal dissemination who was treated with nab-paclitaxel and ramucirumab following nivolumab and developed sclerosing cholangitis. Endoscopic retrograde cholangiography showed irregular narrowing and widening of the entire intrahepatic biliary system. Intriguingly, the patient receiving second-line chemotherapy with nab-paclitaxel plus ramucirumab prior to being administered nivolumab, however, he had experienced progressive disease. Thereafter, the administration of fourth-line chemotherapy with nab-paclitaxel and ramucirumab following nivolumab resulted in a clinical response. Nivolumab may enhance the efficacy of the subsequent chemotherapy regimens but also induce sclerosing cholangitis.

Ischemic Damage Represents the Main Risk Factor for Biliary Stricture After Liver Transplantation: A Follow-Up Study in a Danish Population

BACKGROUND

Biliary complications (BC) are frequently observed following liver transplantation. The aim of the present retrospective study, conducted at an outpatients' tertiary care hospital, was to determine the incidence of biliary complications and risk factors associated with their development in liver transplantation (lT) patients.

MATERIALS AND METHODS

The medical records were reviewed for all patients who underwent liver transplantation at the Rigshospitalet, Copenhagen, Denmark, from 2000 to 2011 and were referred to the Aarhus University Hospital for follow-up. Patients who died within 3 months of surgery or had incomplete clinical information were excluded. All data for demographic characteristics and possible risk factors for development of biliary stricture were collected. Fifty-one patients were included.

RESULTS

The median age at transplantation was 40 (range=7-64) years, and 53% of patients were males. Biliary complications occurred in 18 patients (35%), the majority of whom developed strictures (12 patients, 24%). Univariate and multivariate analyses revealed that cytomegalovirus infection (p=0.008), hepatic artery obstruction (p=0.03) and hepatic artery graft abnormalities (p=0.03) were independent risk factors for the development of biliary strictures.

CONCLUSION

One-third of patients presented biliary complications after liver transplantation, among which biliary strictures were the most common. Cytomegalovirus infection, hepatic artery stenosis and anatomical abnormality of the graft's hepatic artery are independent risk factors for the development of biliary stricture.

Infections in Liver Transplantation

Liver transplantation has become an important treatment modality for patients with end-stage liver disease/cirrhosis, acute liver failure, and hepatocellular carcinoma. Although surgical techniques and immunosuppressive regimens for liver transplantation have improved significantly over the past 20 years, infectious complications continue to contribute to the morbidity and mortality in this patient population. The use of standardized screening protocols for both donors and recipients, coupled with targeted prophylaxis against specific pathogens, has helped to mitigate the risk of infection in liver transplant recipients. Patients with chronic liver disease and cirrhosis have immunological deficits that place them at increased risk for infection while awaiting liver transplantation. The patient undergoing liver transplantation is prone to develop healthcare-acquired infections due to multidrug-resistant organisms that could potentially affect patient outcomes after transplantation. The complex nature of liver transplant surgery that involves multiple vascular and hepatobiliary anastomoses further increases the risk of infection after liver transplantation. During the early post-transplantation period, healthcare-acquired bacterial and fungal infections are the most common types of infection encountered in liver transplant recipients. The period of maximal immunosuppression that occurs at 1–6 months after transplantation can be complicated by opportunistic infections due to both primary infection and reactivation of latent infection. Severe community-acquired infections can complicate the course of liver transplantation beyond 12 months after transplant surgery. This chapter provides an overview of liver transplantation including indications, donor-recipient selection criteria, surgical procedures, and immunosuppressive therapies. A focus on infections in patients with chronic liver disease/cirrhosis and an overview of the specific infectious complications in liver transplant recipients are presented.

Cytomegalovirus infection in living donor liver transplant recipients significantly impacts the early post-transplant outcome: A single center experience

BACKGROUND

Cytomegalovirus (CMV) is the most common viral infection in liver transplant recipients that influences the outcomes of liver transplantation. However, its impact on early outcomes following living donor liver transplantation (LDLT) is not fully defined in the Indian subcontinent. This study was done to assess the impact of CMV infection on early post-transplant outcomes in LDLT recipients.

METHODS

Out of 272 LDLTs performed from January 2012 to April 2013, 151 recipients underwent CMV viral load analysis in plasma within 90 days post LDLT based on clinical suspicion. Patients with CMV infection (n = 55) were compared with those without CMV infection (n = 96).

RESULTS

The median time interval of CMV infection from LDLT was 25 days (range 2-90 days). The mean age of study population was 48.92 years. About 116 (76.8%) of the patients were male. Hepatitis C virus (HCV) (39.1%)-related chronic liver disease (CLD) was most common indication for liver transplant. No statistically significant difference was observed in etiology of liver disease (P = .38), Chid-Turcotte-Pugh (CTP) (P = .41), and Model for End-stage Liver Disease (MELD) (P = .12) scores between the groups. Patients with CMV infection had significantly higher incidence of acute cellular rejection (16.1% vs 5.4%, P = .02); longer ICU stay (P = .01); and a higher overall 90-day mortality (24.2% vs 6.7%, P = .001). Bacteremia and fungemia were significantly more common in the CMV infection group.

CONCLUSION

Cytomegalovirus infection significantly influences the early post LDLT outcomes and contributes to increased overall mortality.

Cytomegalovirus Infection in Liver Transplant Recipients: Current Approach to Diagnosis and Management

Cytomegalovirus (CMV) infection is the most common viral infection in liver transplant recipients, affecting post-transplant patients and graft survival. Recent advances in diagnosis and management of CMV have led to marked reduction in incidence, severity, and its associated morbidity and mortality. CMV DNA assay is the most commonly used laboratory parameter to diagnose and monitor CMV infection. Current evidence suggests that both pre-emptive and universal prophylaxis approaches are equally justified in liver transplant recipients. Intravenous ganciclovir and oral valganciclovir are the most commonly used drugs for treatment of CMV disease. Most of the centre use valganciclovir prophylaxis for prevention of CMV disease in liver trasplant recipient. The aim of this article is to review the current standard of care for diagnosis and management of CMV disease in liver transplant recipients.

Late cytomegalovirus infection in children: High incidence of allograft rejection and hepatitis in donor negative and seropositive liver transplant recipients

The complications and outcome associated with late CMV infection and disease on the graft are poorly characterized in PLT recipients. We studied the overall incidence, risk factors, and outcome of late CMV infection and disease (infection 6 months after transplant) in 180 PLT recipients admitted between 2008 and 2011 at the King's College Hospital. Antiviral prophylaxis of intravenous ganciclovir was given only to the D+R- group starting at day 7 post-transplant. The remaining groups (D-R+, D+R+, and D-R-) received pre-emptive therapy when they have CMV viremia above cut-off value and treatment for symptomatic CMV infection. The overall incidence of late CMV infection and disease was 9.4% (19/180) and 14.5% (19/130) in D+R-, D-R+, D+R- groups. The D-R+ group had the highest incidence of hepatitis (37.5%) and significantly increased incidence of CMV disease, and single and multiple acute rejection episodes when compared to the D+R- group, which received prophylaxis. The late CMV infection and disease in pediatric LT recipients was comparable to adult LT recipients despite variable duration of antiviral prophylaxis. Our results show that D-R+ group had highest rate of hepatitis and rejection episodes, associated with high morbidity, and should be considered for antiviral prophylaxis.

Revaluation of vanishing bile duct syndrome

Vanishing bile duct syndrome (VBDS) can result from multiple etiologies, including congenital and genetic diseases, ischemic causes, neoplastic disorders, infections, immune disorders, drugs, idiopathic adulthood ductopenia (IAD) and so on. Recently, lymphoma, HIV/AIDS and drugs were identified to be major etiologies in the reported cases, some of which presented complex clinical course and were contributed by more than one etiological factor. Hepatic biopsy must be done for the diagnosis of VBDS and immunohistochemical staining for cytokeratin 7 (CK7) and CK19 has contributed to the establishment of diagnosis of VBDS. VBDS can be usually treated with symptomatic and supportive therapy, etiological therapy, liver transplantation, ursodeoxycholic acid and immunosuppressive agents. Glucocorticoids can be tried to switch to mycophemolate mofeil or tacrolimus when their effects are poor or side effects are severe. Severe cases ought to receive multimodality therapy besides plasmapheresis.

Role of Polymerase Chain Reaction in the Diagnosis of Cytomegalovirus Infection in Liver Transplant Patients

Eighty-eight formalin-fixed, paraffin-embedded needle biopsies from 58 liver trans plant recipients were analyzed for the presence of cytomegalovirus (CMV) by light microscopy and the polymerase chain reaction (PCR). Twenty-seven biopsies were positive for CMV by both light microscopy and PCR, 41 were negative by both methods, 17 were positive by PCR only, and 3 were positive by light microscopy only. In the absence of cytomegalic cells, immunohistochemical staining was unable to detect CMV that could have been identified by PCR. Serum total bilirubin was higher in patients whose biopsies contained PCR (but not histologic) evidence of CMV infection. No evidence of association of the presence of CMV was found by either PCR or light microscopy with serum levels of aminotransferase or alkaline phosphatase, nor with histologic evidence of rejection or hepatitis. PCR was negative for CMV in 22 liver biopsies from immunocompetent individuals without evidence of hepatic dysfunction. Although PCR can detect the presence of CMV in the absence of cytomegalic cells, the clinical significance of PCR-proven, histologically undetectable CMV in the liver is undetermined. Int J Surg Pathol 2(3):221-226, 1995

Prognostic factors for the evolution and reversibility of chronic rejection in pediatric liver transplantation

OBJECTIVE

Chronic rejection remains a major cause of graft failure with indication for re-transplantation. The incidence of chronic rejection remains high in the pediatric population. Although several risk factors have been implicated in adults, the prognostic factors for the evolution and reversibility of chronic rejection in pediatric liver transplantation are not known. Hence, the current study aimed to determine the factors involved in the progression or reversibility of pediatric chronic rejection by evaluating a series of chronic rejection cases following liver transplantation.

METHODS

Chronic rejection cases were identified by performing liver biopsies on patients based on clinical suspicion. Treatment included maintaining high levels of tacrolimus and the introduction of mofetil mycophenolate. The children were divided into 2 groups: those with favorable outcomes and those with adverse outcomes. Multivariate analysis was performed to identify potential risk factors in these groups.

RESULTS

Among 537 children subjected to liver transplantation, chronic rejection occurred in 29 patients (5.4%). In 10 patients (10/29, 34.5%), remission of chronic rejection was achieved with immunosuppression (favorable outcomes group). In the remaining 19 patients (19/29, 65.5%), rejection could not be controlled (adverse outcomes group) and resulted in re-transplantation (7 patients, 24.1%) or death (12 patients, 41.4%). Statistical analysis showed that the presence of ductopenia was associated with worse outcomes (risk ratio=2.08, p=0.01).

CONCLUSION

The presence of ductopenia is associated with poor prognosis in pediatric patients with chronic graft rejection.

The Impact of Infection on Chronic Allograft Dysfunction and Allograft Survival After Solid Organ Transplantation

Infectious diseases after solid organ transplantation (SOT) are a significant cause of morbidity and reduced allograft and patient survival; however, the influence of infection on the development of chronic allograft dysfunction has not been completely delineated. Some viral infections appear to affect allograft function by both inducing direct tissue damage and immunologically related injury, including acute rejection. In particular, this has been observed for cytomegalovirus (CMV) infection in all SOT recipients and for BK virus infection in kidney transplant recipients, for community-acquired respiratory viruses in lung transplant recipients, and for hepatitis C virus in liver transplant recipients. The impact of bacterial and fungal infections is less clear, but bacterial urinary tract infections and respiratory tract colonization by Pseudomonas aeruginosa and Aspergillus spp appear to be correlated with higher rates of chronic allograft dysfunction in kidney and lung transplant recipients, respectively. Evidence supports the beneficial effects of the use of antiviral prophylaxis for CMV in improving allograft function and survival in SOT recipients. Nevertheless, there is still a need for prospective interventional trials assessing the potential effects of preventive and therapeutic strategies against bacterial and fungal infection for reducing or delaying the development of chronic allograft dysfunction.

CMV infection of human sinusoidal endothelium regulates hepatic T cell recruitment and activation

BACKGROUND & AIMS

Human cytomegalovirus infection (HCMV) is associated with an increased morbidity after liver transplantation, by facilitating allograft rejection and accelerating underlying hepatic inflammation. We hypothesized that human hepatic sinusoidal endothelial cells infected with HCMV possess the capacity to modulate allogeneic T cell recruitment and activation, thereby providing a plausible mechanism of how HCMV infection is able to enhance hepatic immune activation.

METHODS

Human hepatic sinusoidal endothelial cells were isolated from explanted livers and infected with recombinant endotheliotropic HCMV. We used static and flow-based models to quantify adhesion and transendothelial migration of allogeneic T cell subsets and determine their post-migratory phenotype and function.

RESULTS

HCMV infection of primary human hepatic sinusoidal endothelial cells facilitated ICAM-1 and CXCL10-dependent CD4 T cell transendothelial migration under physiological levels of shear stress. Recruited T cells were primarily non-virus-specific CXCR3(hi) effector memory T cells, which demonstrated features of LFA3-dependent Th1 activation after migration, and activated regulatory T cells, which retained a suppressive phenotype following transmigration.

CONCLUSIONS

The ability of infected hepatic endothelium to recruit distinct functional CD4 T cell subsets shows how HCMV facilitates hepatic inflammation and immune activation and may simultaneously favor virus persistence.

Vanishing bile duct syndrome in human immunodeficiency virus infected adults: A report of two cases

Vanishing bile duct syndrome (VBDS) is a group of rare disorders characterized by ductopenia, the progressive destruction and disappearance of intrahepatic bile ducts leading to cholestasis. Described in association with medications, autoimmune disorders, cancer, transplantation, and infections, the specific mechanisms of disease are not known. To date, only 4 cases of VBDS have been reported in human immunodeficiency virus (HIV) infected patients. We report 2 additional cases of HIV-associated VBDS and review the features common to the HIV-associated cases. Presentation includes hyperbilirubinemia, normal liver imaging, and negative viral and autoimmune hepatitis studies. In HIV-infected subjects, VBDS occurred at a range of CD4+ T-cell counts, in some cases following initiation or change in antiretroviral therapy. Lymphoma was associated with two cases; nevirapine, antibiotics, and viral co-infection were suggested as etiologies in the other cases. In HIV-positive patients with progressive cholestasis, early identification of VBDS and referral for transplantation may improve outcomes.

Biliary complications after orthotopic liver transplantation: a review of incidence and risk factors

Biliary complications (BCs) are a common source of morbidity after liver transplantation, leading to long-term and repeated therapies. The incidence of BCs currently ranges from 5% and 25%. Biliary strictures and leaks are the most common complications after deceased donor liver transplantation (DDLT), occurring in 9%-12% and 5%-10% of cases, respectively. Hepatic artery complications are recognized as the major risk factor for BCs; however, other circumstances such as advanced donor age, prolonged cold and warm ischemia times, grafts from donors after cardiac death, occurrence of a previous bile leak, T-tube use, cytomegalovirus infection, or graft steatosis have also been reported to be potential risk factors. Use of various preservation solutions has not significantly improved the biliary complication rate after DDLT. Technical modifications in biliary reconstruction have been proposed to improve outcomes after DDLT; the use of a T-tube for biliary reconstruction continues to be controversial. Non anastomotic strictures (NAS) are recognized to be different from anastomotic strictures. Although they have been associated with ischemic or immunological mechanisms, bile salt toxicity has recently been recognized as a potential factor for NAS. Donation after cardiac death is a significant source of organs that has been associated with decreased graft survival due to the increased BCs.

Primary care of the liver transplant recipient

Chronic rejection of liver graft is an insidious process. Major immunosuppression medications such as tacrolimus, cyclosporin, and sirolimus have dose-related toxicity and narrow therapeutic windows. Certain drugs can affect metabolism of calcineurin inhibitors. Primary care physicians should be vigilant for any unusual opportunistic infection in liver transplant recipients. The quality of life of liver transplant recipients is an important aspect of care by primary care physicians. Alcohol relapse and possibility of depression in liver transplant recipients should be a continuous concern for primary care physicians. This article provides a guideline for the care of liver transplant recipients.

Posttransplant biliary complications in the pre- and post-model for end-stage liver disease era

Biliary complications remain a cause of morbidity after liver transplantation. The aim of this study was to determine whether changes in clinical practice in the era of the Model for End-Stage Liver Disease (MELD) has affected biliary complications after liver transplantation. We retrospectively reviewed all deceased donor liver transplants at a single center. Patients were categorized as pre- or post-MELD (transplant before or after February 28, 2002). A total of 1798 recipients underwent deceased donor liver transplants. Biliary stricture was more common in the post-MELD era (15.4% versus 6.4%, P < 0.001). The strongest risk factors for stricture development were donor age (odds ratio [OR] = 1.01), presence of a prior bile leak (OR = 2.24), use of choledochocholedochostomy (OR = 2.22), and the post-MELD era (OR = 2.30). Bile leak was more common in the pre-MELD era (7.5% versus 4.9%, P = 0.02), with use of a T-tube as the strongest risk factor (OR = 3.38). Surgical factors did not influence the biliary complication rate. In conclusion, even when employing multivariate analysis to allow for factors that may influence biliary strictures, transplant in the post-MELD era was an independent predictor for stricture development. Further studies are warranted to determine the etiology of this increase.

Biliary reconstruction, its complications and management of biliary complications after adult liver transplantation: a systematic review of the incidence, risk factors and outcome

Biliary reconstruction remains common in postoperative complications after liver transplantation. A systematic search was conducted on the PubMed database and 61 studies of retrospective or prospective institutional data were eligible for this review. The study comprised a total of 14,359 liver transplantations. The overall incidence of biliary stricture was 13%; 12% among deceased donor liver transplantation (DDLT) patients and 19% among living donor liver transplantation (LDLT) recipients. The overall incidence of biliary leakage was 8.2%, 7.8% among DDLT patients and 9.5% among LDLT recipients. An endoscopic strategy is the first choice for biliary complications; 83% of patients with biliary stricture were treated by endoscopic modalities with a success rate of 57% and 38% of patients with leakage were indicated for endoscopic biliary drainage. T-tube placement was not performed in 82% of duct-to-duct reconstruction. The incidence of biliary stricture was 10% with a T-tube and 13% without a T-tube and the incidence of leakage was 5% with a T-tube and 6% without a T-tube. A preceding bile leak and LDLT procedure are accepted risk factors for anastomotic stricture. Biliary complications remain common, which requires further investigation and the refinement of reconstruction techniques and management strategies.

Current concepts on cytomegalovirus infection after liver transplantation

Cytomegalovirus (CMV) is the most common viral pathogen that negatively impacts on the outcome of liver transplantation. CMV cause febrile illness often accompanied by bone marrow suppression, and in some cases, invades tissues including the transplanted allograft. In addition, CMV has been significantly associated with an increased predisposition to allograft rejection, accelerated hepatitis C recurrence, and other opportunistic infections, as well as reduced overall patient and allograft survival. To negate the adverse effects of CMV on outcome, its prevention, whether through antiviral prophylaxis or preemptive therapy, is regarded as an essential component to the medical management of liver transplant patients. Two recent guidelines have suggested that antiviral prophylaxis or preemptive therapy are similarly effective in preventing CMV disease in modest-risk CMV-seropositive liver transplant recipients, while antiviral prophylaxis is the preferred strategy over preemptive therapy for the prevention of CMV disease in high-risk recipients [CMV-seronegative recipients of liver allografts from CMV-seropositive donors (D+/R-)]. However, antiviral prophylaxis has only delayed the onset of CMV disease in many CMV D+/R- liver transplant recipients, and at least in one study, such occurrence of late-onset primary CMV disease was significantly associated with increased mortality after liver transplantation. Therefore, optimized strategies for prevention are needed, and aggressive treatment of CMV infection and disease should be pursued. The standard treatment of CMV disease consists of intravenous ganciclovir or oral valganciclovir, and if feasible, one should also reduce the degree of immunosuppression. In one recent controlled clinical trial, valganciclovir was found to be as effective and safe as intravenous ganciclovir for the treatment of mild to moderate CMV disease in solid organ (including liver) transplant recipients. In this article, the authors review the current state and the future perspectives of prevention and treatment of CMV disease after liver transplantation.

Defining the risks for cytomegalovirus infection and disease after solid organ transplantation

Cytomegalovirus continues to be one of the most clinically significant infections after solid organ transplantation. Classic definitions of patients at high risk for infection and tissue-invasive disease are focused on recipient-donor serostatus, type of organ transplanted, and overall level of immunosuppression. However, recent trends in clinical practice call for a reevaluation of cytomegalovirus infection risks after solid organ transplantation. Indeed, whereas early-onset cytomegalovirus infection is usually controlled by antiviral prophylaxis with ganciclovir and derivatives, delayed- and late-onset cytomegalovirus infection can develop after the completion of a course of preventive therapy. In addition, indirect effects of cytomegalovirus infection may occur as a result of persistent low-level viremia. Suboptimal dosing of antiviral drugs due to specific drug toxicities may result in the development of ganciclovir-resistant cytomegalovirus disease. The relationship between organ allograft rejection and cytomegalovirus infection and disease has been recognized for some time. Transplantation of increasing numbers of extended-criteria donor organs increases the risk of delayed graft function and acute rejection, prompting the use of more intensive immunosuppression. In addition, the trend to spare long-term exposure to calcineurin inhibitors has contributed to a resurgence in the use of polyclonal T-cell induction immunosuppressive agents, which may reduce host anticytomegalovirus immunity. We discuss the current trends in solid organ transplantation that provide a foundation for defining risks for cytomegalovirus infection and disease, including identification of patients who would benefit from more aggressive cytomegalovirus monitoring and prevention strategies.

The pathogenesis and treatment of chronic allograft nephropathy

Despite improvements in immunosuppressive therapy, long-term allograft survival after kidney transplantation remains as low as 50%. Chronic allograft nephropathy (CAN) is a major cause of late graft loss in renal transplant recipients. The histopathologic signs of CAN-interstitial fibrosis, tubular atrophy, glomerulopathy and vasculopathy-are nonspecific; therefore, the 2007 Banff classification dispensed with the term CAN in favor of 'interstitial fibrosis and tubular atrophy without evidence of any specific etiology'. In this Review, however, the term CAN is used to describe a clinical syndrome that is characterized by progressive decline in renal function from 3 months after transplantation, accompanied by the development of proteinuria and hypertension. The pathogenesis of CAN is complex and incompletely understood, and involves several immunological and non-immunological factors. We discuss the contributory roles of acute rejection, donor age, anti-human-leukocyte-antigen antibodies, calcineurin inhibitor nephrotoxic effects, viral infection, hypertension and hyperlipidemia. The prevention and treatment of CAN needs multidisciplinary strategies. Early detection by means of protocol biopsy and calculation of glomerular filtration rate is the first step, followed by management of modifiable risk factors.

Immunobiology of human cytomegalovirus: from bench to bedside

SUMMARY

Following primary infection, human cytomegalovirus (HCMV) establishes lifelong latency and periodically reactivates without causing symptoms in healthy individuals. In the absence of an adequate host-derived immune response, this fine balance of permitting viral reactivation without causing pathogenesis is disrupted, and HCMV can subsequently cause invasive disease and an array of damaging indirect immunological effects. Over the last decade, our knowledge of the immune response to HCMV infection in healthy virus carriers and diseased individuals has allowed us to translate these findings to develop better diagnostic tools and therapeutic strategies. The application of these emerging technologies in the clinical setting is likely to provide opportunities for better management of patients with HCMV-associated diseases.

Cytomegalovirus infection after liver transplantation: Current concepts and challenges

Cytomegalovirus (CMV) is a common viral pathogen that influences the outcome of liver transplantation. In addition to the direct effects of CMV syndrome and tissue-invasive diseases, CMV is associated with an increased predisposition to acute and chronic allograft rejection, accelerated hepatitis C recurrence, and other opportunistic infections, as well as reduced overall patient and allograft survival. Risk factors for CMV disease are often interrelated, and include CMV D+/R- serostatus, acute rejection, female gender, age, use of high-dose mycophenolate mofetil and prednisone, and the overall state of immunity. In addition to the role of CMV-specific CD4+ and CD8+ T lymphocytes, there are data to suggest that functionality of the innate immune system contributes to CMV disease pathogenesis. In one study, liver transplant recipients with a specific polymorphism in innate immune molecules known as Toll-like receptors were more likely to develop higher levels of CMV replication and clinical disease. Because of the direct and indirect adverse effects of CMV disease, its prevention, whether through antiviral prophylaxis or preemptive therapy, is an essential component in improving the outcome of liver transplantation. In the majority of transplant centers, antiviral prophylaxis is the preferred strategy over preemptive therapy for the prevention of CMV disease in CMV-seronegative recipients of liver allografts from CMV-seropositive donors (D+/R-). However, the major drawback of antiviral prophylaxis is the occurrence of delayed-onset primary CMV disease. In several prospective and retrospective studies, the incidence of delayed-onset primary CMV disease ranged from 16% to 47% of CMV D+/R- liver transplant recipients. Current data suggests that delayed-onset CMV disease is associated with increased mortality after liver transplantation. Therefore, optimized strategies for prevention and novel drugs with unique modes of action are needed. Currently, a randomized controlled clinical trial is being performed comparing the efficacy and safety of maribavir, a novel benzimidazole riboside, and oral ganciclovir as prophylaxis against primary CMV disease in liver transplant recipients. The treatment of CMV disease consists mainly of intravenous (IV) ganciclovir, and if feasible, a reduction in the degree of immunosuppression. A recent controlled clinical trial demonstrated that valganciclovir is as effective and safe as IV ganciclovir for the treatment of CMV disease in solid organ (including liver) transplant recipients. In this article, the author reviews the current state and the future perspectives of prevention and treatment of CMV disease after liver transplantation.

Late acute rejection after liver transplantation impacts patient survival

Hepatic allograft rejection still remains an important problem following liver transplantation. Early acute rejection, occurring within three months of transplant, is a common event and usually of lesser significance with respect to prognosis than other non-immune-related post-transplant morbidities. However, little is known about late acute rejection (LAR) including factors affecting its occurrence and long-term outcome. In this study, we analyzed LAR including the incidence, clinical risk factors, patient survival, and graft survival. LAR was defined as acute cellular rejection later than six months after liver transplant. Adult patients who had a minimum of 24 months of graft survival were included in this study. A total of 1604 case records of consecutive adult patients (over age 18 yr) who underwent liver transplant between 1985 and 2003 were reviewed. Of the 1604 patients, 305 (19.0%) developed LAR. Patients with primary diagnoses of autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis had higher incidences of LAR, while patients with metabolic disease and retransplant had lower incidence of LAR (p = 0.0024). The LAR group had more female and younger recipients than the no LAR group (p = 0.0026, p = 0.0131, respectively). Patient survival as well as graft survival were significantly lower in the LAR group (p = 0.0083, p = 0.0075, respectively). PTLD was the only significant independent predictor of late rejection. The careful management and treatment of PTLD, especially immunosuppressive management, is important to prevent LAR, which is related to poorer patient survival.

Differential effects of prednisolone and azathioprine on the development of human cytomegalovirus replication post liver transplantation

BACKGROUND

We sought to investigate the impact of different immunosuppressive regimens on human cytomegalovirus (HCMV) incidence and replication dynamics in a cohort of 256 patients after liver transplantation.

METHODS

A time-updated approach was used to determine the risk of developing HCMV replication (>200 genomes/mL blood) within the first 100 days after liver transplantation according to the immunosuppressive regimen being received at specific time points.

RESULTS

In patients receiving tacrolimus, the addition of prednisolone was associated with a significant increased risk of HCMV replication both at baseline (relative rate of infection [RRI]=4.34; P=0.0001) and in a time-updated analysis (RRI=4.68; P=0.0001). However, the addition of azathioprine substantially reduced the risk of HCMV replication to that observed with tacrolimus alone. As expected donor/recipient HCMV serostatus was also a risk factor for viraemia. Multivariable models showed that the tacrolimus plus prednisolone regimen and donor/recipient serostatus were independent risk factors for HCMV replication. Viral replication dynamics showed that the duration of HCMV viraemia, the peak viral load, and the growth rate of HCMV were greatest in patients receiving tacrolimus plus prednisolone although these differences did not reach statistical significance.

CONCLUSIONS

The combination of prednisolone plus tacrolimus as baseline immunosuppression after liver transplantation is associated with a high risk of HCMV replication. This effect can be negated by the addition of azathioprine.

Chlamydia pneumoniae infection is not associated with chronic transplant dysfunction in a rat aortic allograft model

Long-term survival of solid-organ transplants is limited as a result of chronic transplant dysfunction (CTD), which is characterized by occlusion of intragraft vascular tissue due to myointimal hyperplasia. Recent studies have shown a role for infections in vascular pathologies. For example, Chlamydia pneumoniae (Cpn) has been shown to aggravate atherosclerosis, and Cpn immunoglobulin (Ig)G titers correlate with severity of allograft atherosclerosis after cardiac transplantation. In this study, we evaluated the effect of Cpn infection on CTD using a rat aortic allograft model. Orthotopic abdominal aorta transplantations (Tx) were performed with Brown Norway rats as donors and Lewis rats as recipients. Rats were humanely killed at 1 or 8 weeks after surgery. The graft was processed for DNA isolation and histological examination. Influx of macrophages and T cells was assessed using immunohistochemistry. At 1 week after Tx, the perivascular influx of inflammatory cells in the graft was not affected by Cpn infection. Furthermore, only limited numbers of Cpn DNA copies were found in the graft at 1 week after Tx. In addition, Cpn did not alter the severity of myointimal hyperplasia in the rat aortic allograft model at 8 weeks after surgery. Our data suggested that, in the rat aortic allograft model, Cpn infection did not influence the influx of inflammatory cells or the severity of CTD.

Post-transplant reactivation of hepatitis C virus: lymphocyte infiltration and the expression of adhesion molecules and their ligands in liver allografts

Hepatitis C virus (HCV) recurrence after liver transplantation has been associated with chronic rejection. Biopsies from 10 patients with post-transplant HCV were examined for expression of adhesion molecules ICAM-1, VCAM-1, and ELAM-1, number of lymphocytes positive for their ligands LFA-1, VLA-4, and SLeX, and activation markers MHC class II antigens and IL2-R by immunohistochemistry. The phenotypes of the graft-infiltrating lymphocytes were determined. Results were compared to those for patients with normal graft function or rejection. Five recipients with HCV reactivation and one with de novo HCV had a biopsy available showing induction of ICAM-1 in sinusoidal endothelium (p<0.05) and hepatocytes (p<0.01), and Class II antigens in hepatocytes (p<0.01), compared to normal controls. Lymphocytes in the graft infiltrate expressed LFA-1, VLA-4, and Class II antigens, but IL2-R was not significantly expressed. CD3+, CD4+, and CD8+ cells were observed. In our study, HCV recurrence was not associated with acute or chronic rejection, and the inflammation was due to the viral infection.

Influence of donor/recipient HLA-matching on outcome and recurrence of hepatitis C after liver transplantation

The aim of this study was to analyze the effect of human leukocyte antigen (HLA) matching on outcome, severity of recurrent hepatitis C and risk of rejection in hepatitis C positive patients after liver transplantation (LT). In a retrospective analysis, 165 liver transplants in patients positive for hepatitis C virus (HCV) with complete donor/recipient HLA typing were reviewed for recurrence of HCV and outcome. Follow-up ranged from 1 to 158 months (median, 74.5 months). Immunosuppression consisted of either cyclosporine-A- or tacrolimus-based quadruple induction therapy including or an interleukin 2-receptor antagonist. Protocol liver biopsies were performed after 1, 3, 5, 7, and 10 years and staged according to the Scheuer scoring system. The overall 1-, 5-, and 10-year graft survival figures were 81.8%, 69.11 and 62%, respectively. There was no correlation in the study population between number of HLA mismatches and graft survival. The number of rejection episodes increased significantly in patients with more HLA mismatches (P < 0.05). In contrast to this, the fibrosis progression was significantly faster in patients with 0-5 HLA mismatches compared to patients with a complete HLA mismatch. In conclusion, HLA matching did not influence graft survival in patients after LT for end-stage HCV infection, however, despite less rejection episodes, the fibrosis progression increased in patients with less HLA mismatches within the first year after LT.

Viral and fungal infections after liver transplantation--part II

Viral and fungal infections in liver transplant recipients are important to recognize and treat early because of their association with substantial morbidity and mortality. Some viruses, such as cytomegalovirus and human herpesvirus 6, have immunomodulatory properties and can facilitate other infections, including fungal infections. Cytomegalovirus has long been recognized as an important virus in transplantation, but in the past decade other viruses have also received attention in the medical literature because of their association with particular clinical syndromes. Although human herpesvirus 6 has been associated with fever, rash, and encephalitis, a direct cause-and-effect relationship is still lacking. Human herpesvirus 8 has been found to be the cause of Kaposi sarcoma. Molecular techniques (e.g., pp65 antigenemia and polymerase chain reaction) that have been introduced for routine diagnosis of viruses have facilitated the diagnosis of asymptomatic viral infections and the institution of preemptive therapy. Nonetheless, the diagnosis of invasive fungal infections in liver transplant recipients is often delayed and thus associated with high mortality. Despite the use of new antifungal agents in clinical practice and the reduced incidence of fungal infections because of antifungal prophylaxis regimens, mortality has not decreased. Future patient outcomes may improve with early identification of patients who have risk factors for invasive fungal infections and with the development of new molecular diagnostic techniques for early detection.

The effect of HLA mismatches, shared cross-reactive antigen groups, and shared HLA-DR antigens on the outcome after pediatric liver transplantation

The aim of this study was to analyze the effect of human leukocyte antigen (HLA) class I and HLA-DR mismatching, sharing cross-reactive antigen groups (CREGs), and sharing HLA-DR antigens on the outcome after pediatric liver transplantation. Outcome parameters were graft survival, acute rejection, and portal fibrosis. A distinction was made between full-size (FSLTx) and technical-variant liver transplantation (TVLTx). A total of 136 primary transplants were analyzed. The effect of HLA on the outcome parameters was analyzed by adjusted multivariate logistic and Cox regression analysis. HLA mismatches, shared CREGs, and shared HLA-DR antigens affected neither overall graft survival nor survival after FSLTx. Survival after TVLTx was superior in case of 2 mismatches at the HLA-DR locus compared to 0 or 1 mismatch (P = 0.01) and in case of no shared HLA-DR antigen compared to 1 shared HLA-DR antigen (P = 0.004). The incidence of acute rejection was not influenced by HLA. The incidence of portal fibrosis could be analyzed in 62 1-yr biopsies and was higher after TVLTx than FSLTx (P = 0.04). The incidence of portal fibrosis after TVLTx with 0 or 1 mismatch at the HLA-DR locus was 100% compared to 43% with 2 mismatches (P = 0.004). After multivariate analysis, matching for HLA-DR and matching for TVLTx were independent risk factors for portal fibrosis. In conclusion, an overall beneficial effect of HLA matching, sharing CREGs, or sharing HLA-DR antigens was not observed. A negative effect was present for HLA-DR matching and sharing HLA-DR antigens on survival after TVLTx. HLA-DR matching might be associated with portal fibrosis in these grafts.

Hepatitis B Core Antibody Positive Donors as a Safe and Effective Therapeutic Option to Increase Available Organs for Lung Transplantation

BACKGROUND

The use of hepatitis B core antibody (HBcAb+) and hepatitis C antibody (HCV Ab+) positive donors represents one strategy to increase available donor organs, but this remains controversial because of concern for viral transmission to recipients. We hypothesized that isolated HBcAb+ donors represent minimal risk of viral transmission in vaccinated lung transplant (LTx) recipients.

METHODS

A retrospective study was performed of LTx recipients who received HBcAb+ or HCV Ab+ pulmonary allografts. We analyzed liver function studies, viral hepatitis screening tests, quantitative polymerase chain reaction for hepatitis B viral DNA (HBV DNA) and hepatitis C viral RNA (HCV RNA), freedom from bronchiolitis obliterans syndrome, acute rejection, and survival.

RESULTS

Between April 1992 and August 2003, 456 LTx operations were performed. Twenty-nine patients (HB group) received HBcAb+ allograft transplants with a median posttransplant follow-up of 24.5 months. Three critically ill patients (HC group) received HCV Ab+ allografts with a median follow-up of 21.5 months. One-year survival for the HB group is 83% versus 82% for all patients who received non-HB organs (P=0.36). No patient in the HB group developed clinical liver disease because of viral hepatitis, and all patients alive (n=21) at follow-up are, to date, HBV DNA and/or HBcAb negative. All patients in the HC group tested HCV RNA positive; one patient died of liver failure at 22 months.

CONCLUSIONS

Risk of viral transmission with HCV Ab+ allografts seems high after LTx. However, the use of HBcAb+ pulmonary allografts in recipients with prior hepatitis B vaccination seems to be a safe and effective strategy to increase organ availability.

Impact of targeted oral ganciclovir prophylaxis for transplant recipients of livers from cytomegalovirus-seropositive donors

OBJECTIVES

Symptomatic cytomegalovirus (CMV) infection can cause significant morbidity and occasional mortality after liver transplantation. In a previous audit, we showed that donor CMV seropositivity (D+) was a risk factor for symptomatic infection, and we estimated the likely clinical and financial impact of 14 weeks of oral ganciclovir prophylaxis given to recipients of CMV-seropositive organs. In August 2001, we adopted this policy of targeted oral ganciclovir prophylaxis for recipients of CMV-seropositive livers.

METHOD

The additional costs of adopting targeted prophylaxis policy for 1 year, patient and doctor compliance with the new strategy, and its clinical impact were analysed.

RESULTS

Targeted prophylaxis reduced the incidence of symptomatic CMV infection from 9.5% (in the earlier cohort that did not receive prophylaxis) to 5.8% (P = NS). Symptomatic infection was not observed in CMV-seropositive recipients of CMV-seropositive donor livers (P = 0.06 for comparison of the 2 cohorts), but the incidence of symptomatic infection in the CMV-seronegative recipients of CMV-seropositive organs did not change. However, symptomatic infection appeared to be less severe and was delayed by ganciclovir prophylaxis (median time from transplantation to symptom onset 96 vs. 39 days without prophylaxis). Death attributable to CMV infection was not observed in the cohort that received prophylaxis. The additional cost associated with implementation of the prophylaxis strategy was 108,068 pounds sterlings.

CONCLUSION

Targeted CMV prophylaxis with oral ganciclovir reduces the incidence and severity of symptomatic infection and appears to be a cost-effective means of improving outcome following liver transplantation.

Strategies for the prevention of cytomegalovirus infection and disease in pediatric liver transplantation recipients

Cytomegalovirus (CMV) is the most common opportunistic infection following solid organ transplantation. Prevention and management of CMV infection has assumed a higher priority as transplantation has become a frequent treatment for many congenital and acquired disorders, as more potent immunosuppressive agents have become available, new molecular and virologic assays to detect CMV have made their way from research to clinical laboratories and new antiviral medications and biologics have been developed. Management strategies are diverse; however, there are little or no data from large controlled pediatric trials demonstrating the superiority of any particular approach. This review outlines the current strategies employed to prevent CMV infection and disease and summarizes the strengths and limitations of each regimen to guide clinicians in the selection of the optimal preventative approach.

HLA mismatching increases the risk of BK virus nephropathy in renal transplant recipients

BK virus (BKV) nephropathy is a serious complication in kidney transplant recipients that may lead to irreversible graft failure. We have analyzed the degree of donor/recipient HLA compatibility and HLA antigen association in 40 kidney transplant patients with BKV nephropathy in comparison with a control group of 404 unaffected transplant recipients who were on tacrolimus-based immunosuppression with no induction. HLA compatibility was assessed by determining the number of HLA-A, -B, -DR-mismatched antigens. BK virus nephropathy was diagnosed histologically and confirmed by immunochemistry. Univariate and multiple logistic regression statistical analyses have shown a significant association between BKV nephropathy and HLA mismatching. This analysis showed also that BKV nephritis is associated with a greater number of rejection episodes and a higher incidence of steroid-resistant rejection requiring antilymphocyte treatment. There was no association between BKV nephropathy and any specific HLA allele. We propose that HLA mismatching promotes the development of BKV nephropathy through rejection-related inflammatory processes and heavy immunosuppression which cause virus reactivation and injury of the tubular epithelium.

Cytomegalovirus and chronic allograft rejection in liver transplantation

Cytomegalovirus (CMV) remains one of the most frequent viral infections and the most common cause of death after liver transplantation (LT). Chronic allograft liver rejection remains the major obstacle to long-term allograft survival and CMV infection is one of the suggested risk factors for chronic allograft rejection. The precise relationship between cytomegalovirus and chronic rejection remains uncertain. This review addresses the morbidity of cytomegalovirus infection and the risk factors associated with it, the relationship between cytomegalovirus and chronic allograft liver rejection and the potential mechanisms of it.

Strategies for ensuring effective surveillance in post-transplant patients: practical organization and clinical evaluation

Results of renal transplantation have improved steadily over the years. This article reviews the current status of patient and graft survival and discusses major causes of mortality and renal allograft failure. Review of recent literature demonstrates that the traditional enemies of transplantation, acute rejection and opportunistic infections are no longer major problems facing transplantation. Chronic graft nephropathy and death with functioning graft due to cardiovascular disease are the main challenges in the current era. An impact of an early graft thrombosis, recurrent renal disease and post-transplant malignancies are also reviewed. Chronic graft nephropathy is examined in a context of differences between two calcineurin inhibitors, cyclosporin microemulsion and tacrolimus. Strategies of post-transplant surveillance are suggested.

Cytomegalovirus disease following liver transplantation: an analysis of prophylaxis strategies

BACKGROUND

Cytomegalovirus (CMV) infection is an important cause of morbidity and mortality following liver transplantation. Though oral ganciclovir may be used as a prophylactic agent, there is some debate as to whether prophylaxis should be given universally or to targeted 'high risk' sub-groups. We, therefore, analysed the cost-effectiveness of both prophylactic strategies.

METHODS

We performed a retrospective cross-sectional study of adult liver transplant (LT) recipients who developed CMV disease in 1997 and estimated the morbidity and costs associated with disease in these patients. These costs were compared with the estimated cost (based on a previous multi-centre study) of using oral ganciclovir prophylaxis in order to assess the potential cost-effectiveness of introducing different prophylactic regimes.

RESULTS

Universal and targeted prophylaxis would both have prevented all the likely mortality (2 deaths) from CMV disease in that year. The net cost of applying a targeted prophylaxis strategy would have been 206,275 pounds, (i.e. 103,137 pounds per death avoided). The cost per life year saved would have been 15,674 pounds.

CONCLUSION

We suggest that LT units should identify patients at high risk for the development of CMV disease and adopt a targeted prophylactic strategy.