Chronic allograft dysfunction: diagnosis and management. Is it always progressive?

Clinical and Morphologic Diagnostic Assessments of Liver Diseases After Liver Transplant

OBJECTIVES

At the National Scientific Center of Surgery named A. Syzganova, more than 100 liver transplants have been conducted from 2012 to November 2017. Survival and quality of life of patients in the posttransplant period largely depend on the compliance of patients, monitoring of complications, cause of liver disease, the severity of the condition of patients in the pretransplant period, and the technical features of the operation. The aims of the study were to analyze the results of liver biopsy in patients after liver transplant and to evaluate the value of morphologic studies of the liver for the diagnosis of complications in the posttransplant period.

MATERIALS AND METHODS

Liver transplant recipients undergoing liver biopsy between 2012 and 2017 were analyzed. Our study included 40 liver biopsies in 29 patients after orthotopic liver transplant who fulfilled the inclusion criteria.

RESULTS

In 51.7% of cases in patients (that is, in 15 of 29 patients), biopsy data revealed changes characteristic of rejection. Biliary complications were found in 10.34% of patients, recurrent liver diseases were confirmed in 17.24% of patients, 3.45% of patients had confirmed cholangitis, and 6.90% of patients were diagnosed with liver steatosis.

CONCLUSIONS

Histopathology assessment of allograft liver biopsies plays an important role in the differential diagnosis of posttransplant complications and in identifying the cause of graft damage; having this information can lead to the appropriate therapeutic intervention.

Post-operative imaging in liver transplantation: State-of-the-art and future perspectives

Orthotopic liver transplantation (OLT) represents a major treatment for end-stage chronic liver disease, as well as selected cases of hepatocellular carcinoma and acute liver failure. The ever-increasing development of imaging modalities significantly contributed, over the last decades, to the management of recipients both in the pre-operative and post-operative period, thus impacting on graft and patients survival. When properly used, imaging modalities such as ultrasound, multidetector computed tomography, magnetic resonance imaging (MRI) and procedures of direct cholangiography are capable to provide rapid and reliable recognition and treatment of vascular and biliary complications occurring after OLT. Less defined is the role for imaging in assessing primary graft dysfunction (including rejection) or chronic allograft disease after OLT, e.g., hepatitis C virus (HCV) recurrence. This paper: (1) describes specific characteristic of the above imaging modalities and the rationale for their use in clinical practice; (2) illustrates main imaging findings related to post-OLT complications in adult patients; and (3) reviews future perspectives emerging in the surveillance of recipients with HCV recurrence, with special emphasis on MRI.

Chemokines in chronic liver allograft dysfunction pathogenesis and potential therapeutic targets

Despite advances in immunosuppressive drugs, long-term success of liver transplantation is still limited by the development of chronic liver allograft dysfunction. Although the exact pathogenesis of chronic liver allograft dysfunction remains to be established, there is strong evidence that chemokines are involved in organ damage induced by inflammatory and immune responses after liver surgery. Chemokines are a group of low-molecular-weight molecules whose function includes angiogenesis, haematopoiesis, mitogenesis, organ fibrogenesis, tumour growth and metastasis, and participating in the development of the immune system and in inflammatory and immune responses. The purpose of this review is to collect all the research that has been done so far concerning chemokines and the pathogenesis of chronic liver allograft dysfunction and helpfully, to pave the way for designing therapeutic strategies and pharmaceutical agents to ameliorate chronic allograft dysfunction after liver transplantation.

Histopathological causes of late liver allograft dysfunction: analysis at a single institution

Background

We summarize our experience in the pathological diagnosis of late complications of liver transplantation (LT) to better understand the causes of late allograft dysfunction in a population mostly composed of patients with hepatitis B virus (HBV) infection.

Methods

We reviewed 361 post-transplant liver biopsies from 174 patients who underwent LT and first presented with liver function abnormalities 3 months post-procedure. The underlying diseases included HBV-associated liver disease (77%), toxic or alcoholic liver disease (10.3%), hepatitis C virus (HCV)-associated liver disease (8.6%), primary biliary cirrhosis (1.2%), primary sclerosing cholangitis (1.2%), and metabolic disease (1.7%).

Results

The three most common late complications were acute rejection (32.5%), recurrent disease (19.1%), and biliary complication (17.1%). Patients who underwent LT for HBV infection or for drug- or alcohol-related liver disease had a lower incidence of recurring disease than those who underwent transplantation for HCV infection. During post-transplantation months 3-12, acute rejection was the most common cause of allograft dysfunction and recurring disease was the leading cause for allograft dysfunction (p=0.039). The two primary causes of late allograft dysfunction have overlapping histological features, although acute rejection more frequently showed bile duct damage and vascular endothelialitis than recurring HBV infection, and recurring HBV infection had more frequent lobular activity and piecemeal necrosis.

Conclusions

The causes of late liver allograft dysfunction are closely associated with the original liver diseases and the period after LT. Careful attention is required for differential diagnosis between acute rejection and recurrent HBV.

What is the long-term outcome of the liver allograft?

With improved long-term survival following liver transplantation (LT), issues relating to the assessment of the liver allograft in long-term survivors are becoming increasingly relevant. Histological abnormalities are commonly present in late post-transplant biopsies, including protocol biopsies from patients who appear to be well with good graft function. Recurrent disease is the commonest recognised cause of abnormal graft histology, but may be modified by the effects of immunosuppression or interactions with other graft complications, resulting in complex or atypical changes. Other abnormalities seen in late post-transplant biopsies include rejection (which often has different appearances to those seen in the post-transplant period), de novo disease, "idiopathic" post-transplant hepatitis (IPTH) and nodular regenerative hyperplasia. In many cases graft dysfunction has more than one cause and liver biopsy may help to identify the predominant cause of graft damage. Problems exist with the terminology used to describe less well understood patterns of graft injury, but there is emerging evidence to suggest that late rejection, de novo autoimmune hepatitis and IPTH may all be part of an overlapping spectrum of immune-mediated injury occurring in the late post-transplant liver allograft. Careful clinico-pathological correlation is very important and the wording of the biopsy report should take into account therapeutic implications, particularly whether changes in immunosuppression may be indicated. This article will provide an overview of the main histological changes occurring in long-term survivors post-LT, focusing on areas where the assessment of late post-transplant biopsies is most relevant clinically.

Current views on rejection pathology in liver transplantation

Histological assessments continue to play an important role in the diagnosis and management of liver allograft rejection. The changes occurring in acute and chronic rejection are well recognized and liver biopsy remains the 'gold standard' for diagnosing these two conditions. Recent interest has focused on the diagnosis of late cellular rejection, which may have different histological appearances to early acute rejection and instead has features that overlap with so-called 'de novo autoimmune hepatitis' and 'idiopathic post-transplant chronic hepatitis'. There is increasing evidence to suggest that 'central perivenulitis' may be an important manifestation of late rejection, although other causes of centrilobular necro-inflammation need to be considered in the differential diagnosis. There are also important areas of overlap between rejection and recurrent hepatitis C infection and the distinction between these two conditions continues to be a problem in the assessment of liver allograft biopsies. Studies using immunohistochemical staining for C4d as a marker for antibody-mediated damage have found evidence of C4d deposition in liver allograft rejection, but the functional significance of these observations is currently uncertain. This review will focus on these difficult and controversial areas in the pathology of rejection, documenting what is currently known and identifying areas where further clarification is required.

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.

Idiopathic post-transplantation hepatitis following living donor liver transplantation, and significance of autoantibody titre for outcome

Idiopathic post-transplantation hepatitis (IPTH) is a common histology occurring late after liver transplantation. Its natural history and the effect of treatment have not been determined. This study is a matched case-control study that evaluates predictors, outcome and response to treatment for IPTH. Patients were divided by autoantibodies into high-titre (> or = 1:160) and low-titre (<1:160) groups, so as to evaluate clinicopathological differences between the two groups. IPTH was identified in 42 of 944 recipients (4.4%) with tacrolimus-based immunosuppression. They comprised 10 males and 32 females, having median age 6.0 (0-50) years. IPTH presented at a median duration of 5.2 (0.7-10.8) years after transplantation. Particular risk of IPTH was associated with acute rejection, late-onset acute rejection occurring later than 6 month post-transplant, and autoantibody positivity. IPTH was associated with dependence on steroids and frequent adverse outcomes: retransplantation in five (12%); relapse in four (9.5%); and progression of fibrosis in eight (19%). The high-titre group and low-titre group did not differ in their clinicopathological features, response to treatment or outcome. To prevent the development of IPTH, appropriate adjustment of immunosuppression and close follow-up is necessary for patients who suffer repeated episodes of rejection.

Protocol liver allograft biopsies

Protocol liver allograft biopsies are liver biopsies carried out at specific time points according to predetermined guidelines, rather than in response to specific indications such as change in the patient's clinical status or biochemical tests. Use of protocol liver allograft biopsy has been declining over the last decade: an informal survey of 35 transplant units showed that whereas 65% of units undertake protocol biopsies for those grafted for Hepatitis C virus infection, only 25% do so for patients grafted for other indications. In this overview, we consider the arguments against and those in favor of liver biopsies in adult liver allograft recipients. Arguments against the use of protocol liver biopsies are that they biopsies put the patient are associated with a small risk of morbidity and mortality, are expensive, do not provide useful information and do not alter clinical practice. The estimated rate of major complications is 0.6% and the estimated mortality rate 0.02%. However, the argument in favor of protocol biopsies is that even when standard liver tests are normal, there is on-going inflammation in the graft which, if immunosuppression is not altered, will lead to progressive fibrosis, cirrhosis and even graft loss. Conversely, normal liver histology may allow for reduction in the immunosuppression and so lower the risk of the complications associated with immunosuppression. Currently available diagnostic techniques are not yet sufficiently sensitive or specific to provide an accurate reflection of the state of the graft and the presence or absence of graft damage. We conclude that, while there are no clear data showing that protocol liver allograft biopsies are cost effective and lead to improved patient and graft outcome, such biopsies still have a role in the management of the liver transplant recipient.

Cirrhosis after orthotopic liver transplantation in the absence of primary disease recurrence

Liver allograft cirrhosis is a relatively uncommon complication of liver transplantation. Most cases can be attributed to disease recurrence, particularly recurrent hepatitis C. Little is known about the frequency, etiology, and natural history of liver allograft cirrhosis occurring without evidence of recurrent disease. The aim of the present study was to review the clinicopathological features in this group of patients. We retrospectively reviewed data from all adult patients who were transplanted between 1982 and 2002 and survived >12 months after orthotopic liver transplantation (n = 1,287). Cases of histologically proven cirrhosis were identified from histopathological data entered into the Liver Unit Database. A total of 48 patients (3.7%) developed cirrhosis. In 29 of them, cirrhosis could be attributed to recurrent disease (hepatitis C, 11; hepatitis B, 4; autoimmune hepatitis, 4; primary biliary cirrhosis, 2; primary sclerosing cholangitis, 3; nonalcoholic steatohepatitis, 4; alcoholic liver disease, 1). In 9 of the 19 patients without evidence of disease recurrence, another cause of cirrhosis could be identified (de novo autoimmune hepatitis, 4; biliary complications, 4; acquired hepatitis B, 1). In the remaining 10 cases, the cause of cirrhosis remained unknown; their previous biopsies had shown features of chronic hepatitis of uncertain etiology. Three patients in this group died, and the remaining 7 are alive with good graft function 3-12 years after cirrhosis was first diagnosed. The prevalence of "cryptogenic" posttransplant cirrhosis was significantly higher in patients initially transplanted for fulminant seronegative hepatitis (6%) than in those transplanted for other diseases (0.3%). In conclusion, posttransplant cirrhosis without disease recurrence is uncommon, but it is more frequent in patients transplanted for fulminant seronegative hepatitis. Chronic hepatitis is the most frequent underlying pathological process in cases where the cause of cirrhosis remains uncertain.

Natural history of unexplained chronic hepatitis after liver transplantation

Unexplained chronic hepatitis (CH) in the adult liver allograft recipient is not uncommon, but its natural history and clinical significance is unknown. A retrospective study was undertaken of adult liver allograft recipients to determine the frequency and natural history of unexplained CH. We evaluated only those patients who had undergone >or=2 liver biopsies after 6 months and were grafted for indications where recurrent disease could be confidently excluded (alcoholic liver disease [ALD] in those who remained abstinent and fulminant hepatic failure [FHF] from drug reactions). Of 288 patients who were transplanted for ALD or FHF, 30 fulfilled the above criteria. CH was first diagnosed at a median of 15.25 months after transplantation. A total of 24 patients showed mild necroinflammatory changes, and 12 had mild or moderate fibrosis. Liver tests did not reflect the presence or degree of inflammation or fibrosis. After a median of 4 years, necroinflammatory scores were increased in 5; new or progressive fibrosis was noted in 13%; 3 had developed cirrhosis; and 5 developed clinical evidence of portal hypertension. Progressive fibrosis was associated with a high titer of anti-nuclear antibodies (>1:1600) and a portal tract plasma cell infiltrate. There was a trend for correlation between necroinflammatory activity and fibrosis stage, but this did not reach statistical significance (P = 0.06). Serum alkaline phosphatase (P = 0.012) and female gender of the donor (P = 0.033) were associated with progressive fibrosis. Unexplained CH is not uncommon in the liver allograft and may progress to established cirrhosis in a subgroup of patients transplanted for ALD or FHF. Standard liver tests do not reflect the extent of these changes, so protocol liver biopsies may be required to detect these changes. We recommend careful history and follow-up in these patients.

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.

Transplantation pathology

Histological assessments continue to have an important role in the diagnosis and management of graft complications following liver transplantation. For some conditions, such as liver allograft rejection, histology is regarded as the "gold standard" for diagnosis. In other cases, where a likely cause of graft dysfunction has been identified using other methods, liver biopsy provides important additional information (e.g., severity of necroinflammatory activity and fibrosis in recurrent hepatitis C infection) and may point to the presence of an additional or alternative cause for graft dysfunction. In cases where a dual pathology is suspected (eg, hepatitis C and rejection), histological findings can help to identify the main cause of graft dysfunction. This article will focus on the main patterns of damage that are seen in post-transplant liver biopsies and their differential diagnosis. As with the assessment of liver biopsies in the native liver, clinico-pathological correlation is very important. Consideration should also be given to the therapeutic implications of the biopsy report, in particular whether changes in immunosuppression are indicated.

Diagnosis and management of allograft failure

The article focuses on diagnosis and management of allograft failure in four main categories: (1) ischemic-reperfusion injury (primary nonfunction), (2) technical complications (hepatic artery and portal vein thrombosis), (3) chronic rejection, and (4) recurrent disease. It also discusses the complex problems involved in retransplantation for allograft failure.