Current concepts in cell-mediated hepatic allograft rejection leading to ductopenia and liver failure

Recurrent sclerosing cholangitis post-transplant: increased recurrence rates following re-transplantation

Sclerosing cholangitis recurs in some patients following liver transplantation. These high-risk patients may provide clues to the pathogenesis of this disease.

AIMS

In this single-center study, from a high prevalence area, we investigated the incidence of recurrent sclerosing cholangitis following liver transplantation and re-transplantation.

METHODS

A retrospective cohort study of all patients with primary sclerosing cholangitis transplanted in the Irish National Liver Transplant program between 1993 and 2019.

RESULTS

Recurrent sclerosing cholangitis occurred in 23/112 patients (20.7%). Overall patient survival was similar in the recurrence and non-recurrence groups. Nine patients were re-transplanted for recurrent disease. Patients with recurrence were significantly younger (42.7 +  - 2.5 years vs. 49.3 +  - 1.3 p < 0.05), and colectomy post-transplant was performed more frequently in the recurrence group (6/21 vs. 9/81 p < 0.05). Further recurrence after re-transplantation was identified in 6/9 patients and was identified a shorter time after transplant than the first recurrence (median 41.5 months; range 26-53 vs. median 65.5; range 38: p < 0.05).

DISCUSSION/CONCLUSION

Recurrent PSC following liver transplantation is common, particularly in younger patients. It occurs earlier and is more frequent following a second transplant.

Immunosuppressive Drugs in Liver Transplant: An Insight

Liver transplantation (LT) is the standard of care for end-stage liver failure and hepatocellular carcinoma. Over the years, immunosuppression regimens have improved, resulting in enhanced graft and patient survival. At present, the side effects of immunosuppressive agents are a significant threat to post-LT quality of life and long-term outcome. The role of personalized immunosuppression is to reach a delicate balance between optimal immunosuppression and minimal side effects. Today, immunosuppression in LT is more of an art than a science. There are no validated markers for overimmunosuppression and underimmunosuppression, only a few drugs have therapeutic drug monitoring and immunosuppression regimens vary from center to center. The immunosuppressive agents are broadly classified into biological agents and pharmacological agents. Most regimens use multiple agents with different modes of action to reduce the dosage and minimize the toxicities. The calcineurin inhibitor (CNI)-related toxicities are reduced by antibody induction or using mTOR inhibitor/antimetabolites as CNI sparing or CNI minimization strategies. Post-liver transplant immunosuppression has an intensive phase in the first three months when alloreactivity is high, followed by a maintenance phase when immunosuppression minimization protocols are implemented. Over time some patients achieve "tolerance," defined as the successful stopping of immunosuppression with good graft function and no indication of rejection. Cell-based therapy using immune cells with tolerogenic potential is the future and may permit complete withdrawal of immunosuppressive agents.

Glutathione S-Transferase T1 Mismatch Is a Risk Factor for Chronic Ductopenic Rejection of Liver Allografts

The underlying causes of chronic rejection (CR) after liver transplantation (LT) are not completely known. The main aim of this study was to explore the involvement of the minor histocompatibility antigen glutathione S-transferase T1 (GSTT1) in CR. We retrospectively studied 611 patients who underwent LTs at University Hospital Virgen del Rocío between 2003 and 2016 with a median follow-up of 7.4 ± 4.2 years. The GSTT1 genotype was determined by polymerase chain reaction. We defined GSTT1 mismatch as a specific donor/recipient combination in which a recipient who was homozygous for the deletion allele received a transplant from a positive donor. The prevalence of CR in our whole cohort was 11.6% (71/611), and the prevalence in the GSTT1-mismatched group was 18.8% (16/85) versus 10.5% (55/526) in the GSTT1-matched group. In the cyclosporine A (CsA) group, the prevalence was 26.3% (26/99), much higher than the 8.8% (45/512) observed in the tacrolimus (Tac) group. For statistical analysis, the patients were distributed into 2 groups: group 1, regarded as GSTT1 mismatched, which included the donor (D)+/recipient (R)- allelic combination; and group 2, regarded as GSTT1 matched, which included the other allelic combinations of D+/R+, D-/R-, and D-/R+. All relevant clinical information was collected, and a diagnosis of CR was always confirmed by liver biopsy. GSTT1 mismatch (hazard ratio [HR], 1.99; 95% confidence interval [CI], 1.08-3.66; P = 0.03) and use of CsA/Tac (P < 0.001) were independent risk factors for CR. CR increased the risk of mortality (HR, 2; 95% CI, 1.2-3.6; P = 0.01). Out of the 71 CR patients, 12 (16.9%) needed retransplantation. In conclusion, the GSTT1 D+/R- allelic mismatch is an independent risk factor for CR. A long follow-up of LT patients is recommended because the incidence of CR in adults seems to be underestimated.

The Immunological Basis of Liver Allograft Rejection

Liver allograft rejection remains a significant cause of morbidity and graft failure in liver transplant recipients. Rejection is caused by the recognition of non-self donor alloantigens by recipient T-cells. Antigen recognition results in proliferation and activation of T-cells in lymphoid tissue before migration to the allograft. Activated T-cells have a variety of effector mechanisms including direct T-cell mediated damage to bile ducts, endothelium and hepatocytes and indirect effects through cytokine production and recruitment of tissue-destructive inflammatory cells. These effects explain the histological appearances of typical acute T-cell mediated rejection. In addition, donor specific antibodies, most typically against HLA antigens, may give rise to antibody-mediated rejection causing damage to the allograft primarily through endothelial injury. However, as an immune-privileged site there are several mechanisms in the liver capable of overcoming rejection and promoting tolerance to the graft, particularly in the context of recruitment of regulatory T-cells and promotors of an immunosuppressive environment. Indeed, around 20% of transplant recipients can be successfully weaned from immunosuppression. Hence, the host immunological response to the liver allograft is best regarded as a balance between rejection-promoting and tolerance-promoting factors. Understanding this balance provides insight into potential mechanisms for novel anti-rejection therapies.

Effect of diabetes and acute rejection on liver transplant outcomes: An analysis of the organ procurement and transplantation network/united network for organ sharing database

The effects of diabetic status and acute rejection (AR) on liver transplant outcomes are largely unknown. We studied 13,736 liver recipients from the United Network for Organ Sharing/Organ Procurement Transplant Network database who underwent transplantation between 2004 and 2007 with a functioning graft for greater than 1 year. The association of pretransplant diabetes mellitus (PDM), new-onset diabetes after transplant (NODAT), and AR rates on allograft failure, all-cause mortality, and cardiovascular mortality were determined. To determine the differential and joint effects of diabetic status and AR on transplant outcomes, recipients were further stratified into 6 groups: neither (reference, n = 6600); NODAT alone (n = 2054); PDM alone (n = 2414); AR alone (n = 1448); NODAT and AR (n = 707); and PDM and AR (n = 513). An analysis with hepatitis C virus (HCV) serostatus was also performed (HCV recipients, n = 6384; and non-HCV recipient, n = 5934). The median follow-up was 2537 days. The prevalence of PDM was 21.3%. At 1 year after transplant, the rates of NODAT and AR were 25.5% and 19.4%, respectively. Overall, PDM, NODAT, and AR were associated with increased risks for graft failure (PDM, hazard ratio [HR] = 1.31, P < 0.01; NODAT, HR = 1.11, P = 0.02; AR, HR = 1.28, P < 0.01). A multivariate Cox regression analysis of the 6 recipient groups demonstrated that NODAT alone was not significantly associated with any study outcomes. The presence of PDM, AR, NODAT and AR, and PDM and AR were associated with higher overall graft failure risk and mortality risk. The presence of PDM was associated with higher cardiovascular mortality risk. The analyses in both HCV-positive and HCV-negative cohorts showed a similar trend as in the overall cohort. In conclusion, PDM and AR, but not NODAT, is associated with increased mortality and liver allograft failure. Liver Transplantation 22 796-804 2016 AASLD.

Association of interleukin4 gene polymorphisms of recipients and donors with acute rejection following living donor liver transplantation

BACKGROUND

Little is known as to whether the interleukin4 (IL4) gene polymorphisms in recipients or donors affect the incidence of acute cellular rejection (ACR) following living donor liver transplantation (LDLT). Therefore, we determined the effect of IL4 T-33C polymorphisms in recipients and donors on ACR in a large cohort of patients that underwent LDLT.

METHODS

We examined 155 LDLT cases treated at Nagoya University or Kyoto University, Japan, between 2004 and 2009. IL4 T-33C polymorphisms were analyzed in recipients and donors.

RESULTS

Forty-seven recipients (30.3%) developed early ACR. The genotype frequency of IL4 T-33C in the recipients was associated with ACR incidence (P=0.008, P<0.0125 considered significant). Patients with the IL4-33C carrier genotype (C/C or C/T) were significantly associated with a higher incidence of ACR relative to those with the T/T genotype (OR=3.27, 95% CI: 1.56-6.88, P=0.002). The genotype frequencies of IL4 T-33C in the donors were not associated with rejection incidence. In addition, there was no significant effect of IL4 T-33C genotype combinations on ACR incidence in donors and recipients.

CONCLUSIONS

Genotyping of IL4 T-33C in recipients might be useful to stratify the liver transplant recipients according to their risk of ACR.

Immunosuppression withdrawal following liver transplantation

Current immunosuppression regimens in liver transplantation provide excellent short-term survival rates but have many deleterious long-term side effects. They are therefore associated with the higher mortality and morbidity seen in liver transplant recipients compared to the general population and the notion that many liver transplant recipients are over-immunosuppressed is widely accepted. Liver allografts show a greater resistance to alloimmune responses than other solid organ transplants and recent research suggests up to 60% of highly selected recipients could wean off immunosuppression completely. In this review, we look at the evidence from immunosuppression withdrawal trials, the potential benefits of immunosuppression withdrawal and the identification of tolerant transplant recipients.

Antibody-mediated rejection in liver transplantation: current controversies and future directions

Interest in the role of donor-specific human leukocyte antibodies in liver transplantation has been rekindled recently. Emerging evidence suggests that these antibodies may cause injury to the liver allograft. Here we review the clinical literature, highlight controversial results, and propose a path forward for the definition and better understanding of antibody-mediated injury to the liver.

Comparison of short- and long-term outcomes after early versus late liver retransplantation: a single-center experience

BACKGROUND

As the survival of patients after liver transplantation (LT) improves, the requirement of liver retransplantation (reLT) for late graft failure has grown. Although some have reported that the short-term outcome of late reLT was comparable with that of early reLT, it remains unknown whether long-term survival of late reLT is inferior to that of early reLT patients.

MATERIALS AND METHODS

We reviewed early (<6 mo after primary LT) and late (≥6 mo after primary LT) reLT cases performed between January 2000 and December 2010.

RESULTS

Sixteen early and 32 late reLT cases were analyzed. There was no significant difference regarding the number of units of red blood cells transfused during the transplantation between the groups, whereas operative time was significantly longer in the late reLT cases. Graft loss within 3 mo after early and late reLT was 18.6% and 15.6%, respectively. Patient and graft survival rates after 1, 3, 5, and 10 y in the late reLT group were 80.6%, 73.3%, 73.3%, and 67.7% and 80.7%, 69.1%, 63.3%, and 54.3%, respectively, whereas those in the early reLT group were 75.0%, 75.0%, 64.3%, and 64.3% and 81.3%, 75.0%, 64.3%, and 32.1%, respectively. There was no significant difference in patient or graft survival rates between the groups (P = 0.91 and 0.91, respectively).

CONCLUSIONS

Acceptable short- and long-term survival were provided in early and late reLT. The time between the primary LT and reLT does not seem to play significant role in the prognosis of reLT in the long term.

Delivery of a granzyme B inhibitor gene using carbamate-mannose modified PEI protects against cytotoxic lymphocyte killing

Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells protect vertebrates by killing infected or transformed cells using granzyme B (GrB) to induce apoptosis. However, GrB-induced apoptosis of target cells causes inflammatory disease and chronic transplant rejection and so is an important disease target. The aim of this study was to prevent apoptosis of the target cells by delivering a plasmid encoding GrB inhibitor proteinase inhibitor-9 (PI-9) using cationic polymers as a non-viral vector. Polyethyleneimine (PEI, branched, Mn 10 kDa) gives a high degree of gene transfection efficiency in many types of cell lines, but it is highly cytotoxic. To reduce this cytotoxicity, we modified PEI by blocking primary amine groups through nucleophilic addition between primary amine and a protected mannose-functionalized cyclic carbonate (MTC-ipman), generating a carbamate linkage through the ring-opening of the cyclic carbonate. Deprotection of the mannose yielded a PEI polymer that is decorated with the carbohydrate. PEI with 7 or 20 of 67 primary amine groups substituted by the carbohydrate had similar gene binding ability compared to unmodified PEI, leading to almost 100% transfection efficiency of a GFP-reporter plasmid in HEK293T human embryonic kidney cells. Furthermore, modification of PEI resulted in a decrease in the cytotoxicity of PEI/DNA complexes. However, PEI with all primary amine groups blocked was unable to form a complex with DNA, and so reporter transfection was negligible. The PI-9 encoding plasmid was transfected into HEK293T cells effectively using the modified PEIs with the optimal degree of primary amine substitution, protecting up to 80% HEK293T cells from killing by human natural killer-like leukemic YT cells. Therefore, these carbamate-mannose modified PEI/PI-9 encoding plasmid complexes have potential clinical utility in the prevention of chronic transplant rejection and inflammatory disease caused by GrB.

Primary sclerosing cholangitis: a review and update on therapeutic developments

Primary sclerosing cholangitis (PSC) is a chronic, cholestatic, idiopathic liver disease characterized by fibro-obliterative inflammation of the hepatic bile ducts. In a clinically significant proportion of patients, PSC progresses to cirrhosis, end-stage liver disease, and in some cases, cholangiocarcinoma. Despite clinical trials of nearly 20 different pharmacotherapies over several decades, safe and effective medical therapy, albeit critically needed, remains to be established. PSC is pathogenically complex, with genetic, immune, enteric microbial, environmental and other factors being potentially involved and, thus, not surprisingly, it manifests as a clinically heterogeneous disease with a relatively unpredictable course. It is likely that this complexity and clinical heterogeneity are responsible for the negative results of clinical trials, but novel insights about and approaches to PSC may shift this trend. The authors herein provide a review of previously tested pharmacologic agents, discuss emerging fundamental concepts and present viewpoints regarding how identifying therapies for PSC may evolve over the next several years.

Impact of glutathione S-transferase T1 gene polymorphisms on acute cellular rejection in living donor liver transplantation

It has previously been demonstrated that glutathione S-transferase T1 (GSTT1) genetic mismatch between recipient and donor is a risk factor for developing immune-mediated hepatitis following liver transplantation and for antibody-mediated rejection in renal transplantation. Little is known whether the GSTT1 gene polymorphism affects the incidence of acute cellular rejection (ACR) following living donor liver transplantation (LDLT). Patients underwent LDLT at Nagoya University or Kyoto University, Japan, between 2004 and 2009. Genotyping of GSTT1 genes (null or present genotype) was conducted in recipients and donors. A total of 155 LDLT cases were examined. Forty-seven recipients (30.3%) developed early ACR. There was no association of recipient GSTT1 genotype with ACR incidence. However, ACR incidence was significantly higher in recipients transplanted from GSTT1 present genotype donors than in those transplanted from GSTT1 null genotype donors [odds ratio (OR)=2.64, 95% confidence interval (CI)=1.12-5.83, p=0.016]. Moreover, GSTT1 recipient/donor genotype mismatch (present/null or null/present) was significantly associated with ACR development (OR=2.28, 95% CI=1.12-4.61, p=0.022). The genotyping of GSTT1 in recipients and donors might be useful to stratify the liver transplant recipients according to risk of ACR.

ImmuKnow as a diagnostic tool for predicting infection and acute rejection in adult liver transplant recipients: a systematic review and meta-analysis

Immune status monitoring of transplant recipients could identify patients at risk of acute rejection, infection, and cancer, which are important sources of morbidity and mortality in these patients. The ImmuKnow assay provides an objective assessment of the cellular immune function of immunosuppressed patients. Inconclusive results concerning the ability of the ImmuKnow test to predict acute rejection and infection have raised concerns about the predictive value of ImmuKnow in liver transplant recipients. We conducted a systematic literature review to identify studies published up to March 2012 that documented the use of ImmuKnow for monitoring immune function in liver transplant recipients. The study quality was assessed with the Quality Assessment of Diagnostic Accuracy Studies 2 score. We identified 5 studies analyzing ImmuKnow performance for infection and 5 studies analyzing ImmuKnow performance for acute rejection. The pooled sensitivity, specificity, positive likelihood ratio, diagnostic odds ratio, and area under the summary receiver operating characteristic curve were 83.8% [95% confidence interval (CI) = 78.5%-88.3%], 75.3% (95% CI = 70.9%-79.4%), 3.3 (95% CI = 2.8-4.0), 14.6 (95% CI = 9.6-22.3), and 0.824 ± 0.034, respectively, for infection and 65.6% (95% CI = 55.0%-75.1%), 80.4% (95% CI = 76.4%-83.9%), 3.4 (95% CI = 2.4-4.7), 8.8 (95% CI = 3.1-24.8), and 0.835 ± 0.060, respectively, for acute rejection. Heterogeneity was low for infection studies and high for acute rejection studies. In conclusion, the ImmuKnow test is a valid tool for determining the risk of further infection in adult liver transplant recipients. Significant heterogeneity across studies precludes the conclusion that ImmuKnow identifies liver transplant patients at risk for rejection.

A single centre prospective study of liver function tests in post liver transplant patients

Liver transplantation means surgical replacement of a diseased liver with a healthy liver. The survival rate used to be 30 % after 1 year and LTx was considered to be the last procedure when all medical or surgical intervention failed. Advances in donor organ preservation, surgical techniques, patient selection, immunosuppressive regimens and treatments for opportunistic infections all have contributed to substantially improve the survival rates. Despite substantial technological, medical and surgical advances, liver transplantation remains a complex procedure that is accompanied by significant morbidity and mortality. The post-operative outcome of each patient varies greatly depending on the patient's pre- operative state, quality of the donated organ and the complexity of the surgery. Complications occur both immediately post transplant and in the long term. Most of the problems can be satisfactorily assessed with a panel of routine LFTs results of which are generated quickly, cheaply on the analyzer which operates 24 h. Liver Function Test identifies the presence of problem but not problem itself. Abnormal results can be meaningful only when used with clinical data, radiological findings. The study includes 75 post LTx patients in three groups adults (non ACR), Pediatrics and ACR. All recipients were on immunosuppressive therapy (tacrolimus, mycophenolate and methylprednisolone), antiviral (ganciclovir), antiprotozoal, antibacterial and antifungal (fluconazole). 5 mL of blood was drawn in plain vacutainer from the post LTx patients every day for 15 days and LFT and GGT was done. Routinely performed liver function tests correlates well with clinical complications involving liver in the transplant patients. Instead of daily testing, may be alternate day analysis of LFT should be sufficient for effective monitoring of patients. The total protein and albumin and the transaminases offer little help in monitoring LFT post LTx. The elevated levels of serum GGT and ALP may be related to chronic immune damage to the transplanted liver. Serum GGT and ALP can be used as early markers for diagnosing biliary complications and can be used to asses adequacy of endoscopic treatment in the group of patients presenting early. Thus, most of the problems can be satisfactorily assed with a panel of routine LFTs generated quickly, cheaply on analyzer which operates 24 h each day. However, it must be emphasized that LFTs may identify the presence of problems but not the problem itself and the abnormal results are meaningful only when correlated with other clinical information.

Present state of immunosuppressive therapy in liver transplant recipients

1. Our increasing understanding of the signaling pathways and cellular interactions in transplant immunobiology has facilitated targeted strategies using novel immunosuppressive agents. 2. The pattern of immunosuppressive drug use in the United States continues to change, and the changes include the use of antibody induction therapy and the agents used in maintenance therapy. 3. The driving forces behind the development of new immunosuppressive regimens are the long-term complications of current immunosuppressive regimens (particularly renal dysfunction and metabolic disturbances).

Hepatocyte cytokeratin 7 expression in chronic allograft rejection

We examined hepatocyte cytokeratin 7 (CK7) expression in chronic allograft rejection (CR), a ductopenic condition in which this has not been systematically evaluated, in 20 patients with the clinicopathologic diagnosis of CR and age-, sex-, and native-disease-matched control subjects. We also studied baseline biopsy specimens from both groups. Three pathologists independently reviewed H&E- and CK7-stained sections, counting interlobular bile ducts (BDs) and portal tracts (PTs), noting the morphologic pattern of injury and scoring hepatocyte CK7 expression (0, none; 1+, rare; 2+, multifocal, predominantly periportal; 3+, extension into the lobule; 4+, diffuse). Mean BD/PT ratios and CK7 scores were calculated. The mean BD/PT ratio (0.58) and CK7 score (1.01) for the "CR, diagnostic" group were significantly different from all other group means (P < .05); no other comparisons were significant (P > .05). A CK7 score of 1 or more was observed in 9 (56%) of 16 CR specimens and in 3 (7%) of 41 remaining specimens. Hepatocyte CK7 expression is frequently noted in CR, and it would appear to reflect ductopenia. CK7 staining may be a useful diagnostic adjunct in evaluation of transplant liver biopsy specimens.

Tissue factor expression demonstrates severe sinusoidal endothelial cell damage during rejection after living-donor liver transplantation

BACKGROUND/PURPOSE

Since it is well known that endothelial cells may be important targets during rejection after living-donor liver transplantation, in this study we investigated liver sinusoidal endothelial cell (SEC) damage during rejection by focusing on thrombomodulin (TM) and hyaluronic acid (HA) as plasma markers of SEC damage. We also examined tissue factor (TF) expression in SECs, because damage to endothelial cells leads to immediate activation of the coagulation system, with the damage being triggered mainly by TF.

METHODS

Living-donor liver transplantation was performed at Mie University Hospital between March 2002 and December 2007; there were 8 patients with rejection (4 with acute cellular rejection and 4 with chronic rejection) and 32 patients without rejection. Liver biopsy tissue was immunostained with an anti-TF antibody, and assessed for SEC damage. In addition, total RNA was extracted from liver biopsy tissue and tested for TF mRNA expression by reverse-transcription polymerase chain reaction (RT-PCR).

RESULTS

The plasma TM level was significantly higher in the rejection group than in the non-rejection group. TF expression was observed in SECs, in infiltrating inflammatory cells, and in the vascular endothelium in the rejection group. TF mRNA expression was significantly higher in the rejection group than in the non-rejection group.

CONCLUSIONS

We demonstrated that TF expression revealed severe SEC damage in grafted liver during both acute cellular rejection and chronic rejection.

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.

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.

Association of mast cells and liver allograft rejection

MCs are important effector cells in a broad range of immune responses. Their role in liver allograft rejection is not clear. Twenty-one liver transplant recipients (mean age +/- s.d.; 10.2 +/- 4.1 yr) who experienced a rejection episode are included in this study. Biopsy specimens from normal livers (allograft biopsy with normal histopathology n = 5 and naive livers n = 6), transplanted livers with CR (n = 5), and transplanted livers with ACR (n = 26) were studied. The total number of PT in each biopsy specimen was documented, and the number of PT that contained MCs was expressed as a percentage of the total number of PT. MCs, percentage of PT containing MCs and the average number of MCs/PT was significantly higher in rejection specimens than in control biopsy samples. All parameters were significantly higher in CR group than AR groups. Increasing grades of rejection was also associated with progressively more MCs and MC/PT (r = 0.68 p = 0.000; r = 0.58 p = 0.002). Only serum bilirubin level was related to the MCs in AR group. Only MC/PT was detected as an independent predictor of graft survival (p = 0.011, RR 2.87 95% CI 1.3-6.5). Despite the fact that the role of MCs in liver allograft rejection is still unknown; they exist in inflammatory infiltrates during pediatric liver allograft rejection. MC-rich portal infiltrates may distinguish chronic liver rejection from other inflammatory states such as AR, hepatitis and biliary obstruction.

Bioinformatic approach for cholangiocyte pathophysiology

The heterogeneous functions of cholangiocytes regulate the physiology of the biliary epithelium regarding secretory, proliferative and apoptotic activities. However, due to their technical difficulties for isolation and culture, the pathophysiology of cholangiocytes was poorly understood. Recently, cutting-edge technology, such as the microarray, has given the opportunity for investigating cholangiocytes. We have found the distinct expression profiles of two murine cholangiocytes lines, termed small and large, revealed by microarray analysis. The features of the two cholangiocyte cell lines, categorized partly according to gene ontology, indicate the specific physiological role of each cell line. Namely, large cholangiocytes are characterized as "transport" and "immune/inflammatory responses". In contrast to large, small cholangiocytes are associated with properties of limited physiological functional ability and proliferating/migratingpotential with specific molecules like Eph receptors, comparable to mesenchymal cells. Further analysis using other modern technology, such as proteomics, will provide more information to understand the pathophysiology of cholangiocytes. These novel methods enable us to investigate the key molecules and their mutual relationship. Although the evaluation of some important biological regulatory processes like protein modification requires methodologies other than microarray, microarray technology is anticipated to grow with the development of data-analysis theory for the comprehension of cellular cross-talk in the liver.

Bioinformatic approach for understanding the heterogeneity of cholangiocytes

It is remarkable that microarray technologies have nearly reached a pinnacle. Establishment of further analysis and management of enormous data derived from microarray technology is currently the highest priority. The heterogeneous functions of cholangiocytes regulate the pathophysiology of the biliary epithelium in relation to secretory, proliferative and apoptotic activities. Distinct expression profiles of two murine cholangiocyte lines, termed small and large have been revealed by microarray analysis. The features of the two cholangiocyte cell lines, categorized partly according to gene ontology, indicate the specific physiological role of each cell line. The large cholangiocytes are characterized as “transport” and “immune/ inflammatory responses”. In contrast, small cholangiocytes are associated with properties of limited physiological functional ability and proliferating/migrating potential with specific molecules like Eph receptors, comparable to mesenchymal cells. 'Omic study will be of great help in understanding the heterogeneity of cholangiocytes.

Macrophage activating syndrome is associated with lobular hepatitis and severe bile duct injury with cholestasis

Macrophage activating syndrome (MAS) is a rare hematological disorder associated with uncontrolled systemic T-cell activation. Persistent fever, fatigue and hepatosplenomegaly are frequent clinical manifestations, whereas hyperferritinemia, elevated serum lactate dehydrogenase levels and cytopenia are key criteria for the diagnosis of MAS. The nature of liver pathology in MAS has been partially elucidated but destructive biliary lesions have been rarely described. This report illustrates four cases of MAS developing marked cholestasis, leading to one case of biliary cirrhosis necessitating liver transplantation. Histologically, liver involvement was characterized in all cases by acute lobular hepatitis, marked hepatocyte apoptosis and small bile duct injury similar to the vanishing bile duct syndrome. Immuno-histological studies showed that the inflammatory changes and bile duct lesions were dominated by the presence of activated macrophages and T-cells, in particular CD8+ lymphocytes, and in part NK-cells. These findings suggest that in MAS, various T-cell triggers such as infection, autoimmune disease and malignancy might result in the release of cytokines, which in turn activate macrophages to trigger a systemic acute phase response and local tissue damage. This communication suggests that a macrophage, T- and NK-cell network is operational in the pathogenesis of the cholangiocyte, hepatocyte and sinus endothelial cell damage in MAS.

Tacrolimus-induced cholestatic syndrome following pediatric liver transplantation and steroid-resistant graft rejection

Several factors may contribute to post-transplant cholestatic complications after liver transplantation. These include ischemic reperfusion injury, hypoperfusion, bile duct strictures, and hepatotoxic drugs. Up to now, there have been no publications on tacrolimus cholestatic toxicity in clinical transplantation when the drug was used in therapeutic doses. We describe six pediatric liver graft recipients in whom cholestatic complications developed under a tacrolimus-based immunosuppression following liver transplantation and all of them suffered from previous steroid-resistant graft rejection. The overall incidence of cholestatic syndrome was 5.4% in children receiving tacrolimus. The immunosuppression was switched back to cyclosporine and prednisolone in all six patients resulting in completely resolved clinical signs and laboratory findings. We conclude from our observations that a cholestatic syndrome following pediatric liver transplantation may be caused by tacrolimus therapy following steroid-resistant graft rejection, even if given in therapeutic doses.

A rat model of chronic allograft liver rejection

INTRODUCTION

The aim of this study was to develop a rat model of chronic irreversible rejection, which is a major causes of late graft loss and retransplantation after orthotopic liver allotransplantation.

METHODS

Allogeneic liver transplantation was performed in a rat combination of Dark Agouti (DA) to Brown Norway (BN). Group A was left without treatment, group B received cyclosporine' (CsA; 1 mg/kg/d) and group C, CsA (4 mg/kg/d). Animals were followed for 6 months. Liver tissue was harvested to construct a time course of histological changes after liver transplantation using histopathological and morphometric techniques. We compared the total histological score of rejection activity index and survival rates.

RESULTS

In untreated animals, irreversible acute rejection developed, all animals died within 15 days. In the low-dose CsA group, all animals that survived more than 30 days developed moderate to severe manifestations of chronic liver rejection, with graft infiltration, ductular damage or proliferation, obliterative arteriopathy, and liver fibrosis. No apparent histological alterations were observed in group C. Survival analysis showed significant differences between the three groups.

CONCLUSIONS

In the rat strain combination of DA --> BN with low-dose immunosuppression, early mild inflammation was followed by the development of chronic rejection.

Tacrolimus in liver transplantation

Tacrolimus has been in clinical use for ten years. It was launched in a hail of publicity following the successful treatment of cases with apparently irreversible rejection using conventional immunosuppressive therapies. Since that time, the overall experience with the drug has increased considerably. The purpose of this article is to review tacrolimus comprehensively, including evidence derived from major clinical trials, to enable the reader to become familiar with its clinical role, including a comparison with its main competitor, cyclosporin. Tacrolimus was discovered in 1984, it predominantly acts via inhibition of T-cell mediated immunity, and to a lesser extent B-cell humoral immunity. The agent was introduced into clinical medicine in 1989 and was soon shown to be a highly effective immunosuppressive agent, receiving approval in 1994 by the Food and Drug Administration (FDA) for primary immunosuppression in adult and paediatric liver transplantation. Tacrolimus has proved to be a major development in transplantation. Whilst the available data have been hindered to some extent by deficiencies of trial design in the major studies, there is still more comparative clinical data available for tacrolimus than for any of its predecessors. The overall balance of risk benefit is considered by many to be tipped in favour of tacrolimus; it is likely that with more long-term follow-up results becoming available in liver and other solid organ transplants, the benefits will appear clearer.

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.

Switching monitoring of emulsified cyclosporine from trough level to 2-hour level in stable liver transplant patients

After orthotopic liver transplantation (OLT) many patients use emulsified cyclosporine. Recent data showed that blood levels 2 hours after dosing (C-2) better reflect systemic exposure to the drug (area under the blood concentration time curve) than trough levels (C-0) do. We investigated difference in dosage, creatinine clearance (CrCl), blood pressure (BP), freedom from rejection, and relation of C-2, C-0, and AUC while switching 31 stable patients more than 6 months after OLT from C-0 to C-2 monitoring. With C-0 between 90 and 150 ng/mL we collected 24-hour urine, while blood samples were taken at t = 0, 1, 2, 3, 4, 6, and 8 hours after dosing to measure cyclosporine, creatinine, liver tests, and blood pressure and calculated AUC and CrCl. Target AUC was calculated based on C-0. Then the dose was adjusted to two subsequent C-2 values of 600 ng/mL +/- 15%, the above was repeated, and the differences were assessed. Cyclosporine dose was reduced in 21/31 patients (68%) and remained unchanged in 10/31 patients (32%) after conversion. Mean lowering was 69 mg daily (26.9 %, P < 0.0001). After dose reduction the mean increase of CrCl was 7.93 ml/min (11.6%, P = 0.016). Only systolic and mean morning BP decreased slightly but significantly. C-2 correlated better with AUC0-12 (r2 = 0.75) than C-0 (r2 = 0.64). However, 13/21 patients had a second AUC below target AUC and 2 of these 13 patients developed rejection after conversion to C-2 levels. In conclusion, while C-0 monitoring frequently results in overdosing and more renal dysfunction, C-2 monitoring may lead to episodes of underdosing and rejection. Therefore better ways of monitoring cyclosporine dosing need to be devised.

Total fibrous obliteration of main portal vein and portal foam cell venopathy in chronic hepatic allograft rejection

CONTEXT

Chronic hepatic allograft rejection is characterized by arteriopathy and bile duct loss. Pathology of the portal vein or its branches is not considered to play a major role in chronic rejection.

OBJECTIVE

A recent case of chronic rejection with total fibrous obliteration of the portal vein at the hilum and graft loss prompted us to retrospectively analyze cases of failed allografts for portal vein changes.

DESIGN

Six cases of failed hepatic allograft recorded in our files from 1994 to 1998 were selected for the study. For comparison, 4 cases of hepatitis C cirrhosis were included. Clinical features, including arteriograms or Doppler studies, were reviewed whenever available. Sections taken from the hilum and random parenchyma stained with routine hematoxylin-eosin, elastic van Gieson, and Masson trichrome were examined by 3 experienced liver pathologists in a randomized, blinded fashion.

RESULTS

Significant hepatic artery occlusion with foam cell change and bile duct loss was seen in all cases of chronic rejection (3/3), but not in the other cases. Foam cell change in the portal vein at the hilum (3/3) and occasionally into the distal branches (2/3) with variable occlusion of the lumen was seen only in cases of chronic hepatic allograft rejection. Mild luminal narrowing was observed in all the cases of cirrhosis (4/4) as a result of phlebosclerosis, most likely representing a change secondary to portal hypertension. Total obliteration of the portal vein at the hilum was seen in the index case (case 1) only.

CONCLUSION

Portal venopathy can be a significant finding in chronic hepatic allograft rejection and may contribute to graft dysfunction or failure. Two-vessel disease must be considered in cases of chronic hepatic allograft rejection, and pathologists should thoroughly examine the hilum in explanted hepatic allografts.

Intrahepatic cholestasis after liver transplantation

Cholestasis is a common sequela of liver transplantation. Although the majority of cases remain subclinical, severe cholestasis may be associated with irreversible liver damage, requiring retransplantation. Therefore, it is essential that clinicians be able to identify and treat the syndromes associated with cholestasis. In this review, we consider causes of intrahepatic cholestasis. These may be categorized by time of occurrence, namely, within 6 months of liver transplantation (early) and thereafter (late), although there may be an overlap in their causes. The causes of intrahepatic cholestasis include ischemia/reperfusion injury, bacterial infection, acute cellular rejection, cytomegalovirus infection, small-for-size graft, drugs for hepatotoxicity, intrahepatic biliary strictures, chronic rejection, hepatic artery thrombosis, ABO blood group incompatibility, and recurrent disease. The mechanisms of cholestasis in each category and the clinical presentation, diagnosis, treatment, and outcome are discussed in detail.

Different immunosuppressive regimens and recurrence of primary sclerosing cholangitis after liver transplantation

Primary sclerosing cholangitis (PSC) is the fourth leading diagnosis in liver transplant recipients in the United States. The disease is known to recur in 15% to 30% of liver transplant recipients. We set out to investigate how different immunosuppression regimens affected natural history of PSC after liver transplantation at our center. We reviewed records of all patients who underwent a liver transplantation at our institution in between 1988 and 2000 and had a diagnosis of PSC at the time of liver transplantation. Primary sclerosing cholangitis recurred in 15 of 71 patients (21.1%) who had complete records and survived more than 30 days after liver transplantation. Although recurrence of primary sclerosing cholangitis was most often seen (but not statistically significantly so) in patients who received maintenance corticosteroids, the time to recurrence was not significantly different between those who were treated with maintenance, those who were not successfully weaned, and those who successfully weaned off corticosteroids within 3 months after liver transplantation. Orthoclone (OKT3) therapy (Ortho-Biotech, Inc., Raritan, NJ) was associated with a higher risk of primary sclerosing cholangitis recurrence (29% versus 10%, P <.05). Recurrence was not influenced by immunosuppression with either cyclosporine or tacrolimus. Coexistent inflammatory bowel disease was a cause of failure to wean off corticosteroids, was associated with a shorter time to recurrence of sclerosing cholangitis, and was responsible for significant comorbidity (colon cancer in 7.3%). Primary sclerosing cholangitis recurrence is commonly seen after liver transplantation. More immunosuppression seems to be detrimental to the outcome of our patients with sclerosing cholangitis: use of OKT3 was associated with a greater incidence of recurrence. Length of corticosteroid use did not affect timing or risk of recurrence, and because it has been proven that early corticosteroid withdrawal after liver transplantation is beneficial, we continue to recommend this practice.

The management of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic hepatobiliary disease that usually progresses to biliary cirrhosis and liver failure; it also predisposes to cholangiocarcinoma. The cause of PSC is unknown, although evidence suggests that the tissue damage is mediated by the immune system. There is an unexplained close association between PSC and inflammatory bowel disease, particularly in ulcerative colitis, which coexists in the majority of patients with PSC. No medical therapy has been proven to halt or reverse disease progression; however, recent preliminary evidence suggests that ursodeoxycholic acid (UDCA) in a high dose of 20 to 25 mg/kg may slow the disease process. Evidence from a pilot study suggests that the combination of UDCA and immunosuppressive therapy, such as prednisolone or azathioprine, may also increase efficacy. For patients with end-stage PSC, liver transplantation remains the only effective therapy, although there is clear evidence that PSC may recur in the liver allograft.

Hepatic expression of IL-15 mRNA is associated with liver graft acceptance

BACKGROUND

Acute allograft rejection continues to be a major cause of morbidity following organ transplantation. The aim of this study was to investigate the local expression of a range of immunomodulatory molecules which may be mediating rejection of, or tolerance to, liver allografts.

METHODS

RNA was extracted from 31 protocol liver biopsies taken 7-10 days post-transplantation, reverse transcribed and screened by a sensitive RT-PCR for a wide range of cytokines and other immunomodulatory molecules. The mRNA profile of each biopsy was subsequently related to the histological and clinical status of the graft. Samples of RNA isolated from activated leukocytes and T cell clones, and from normal liver, were used as controls to compare to the 'immunological snapshot' obtained from the biopsies.

RESULTS

Presence of tumour necrosis factor-alpha, fas ligand, granzyme B and perforin mRNA in most of the liver biopsies reflected the occurrence of cell-mediated immune reactions. However, the expression of only one cytokine, interleukin-15 (IL-15), was significantly more frequent in allografts that showed no histological or biochemical signs of rejection during the early post-transplant period. Using an in vitro model it was demonstrated that recombinant IL-15 expands tenfold the number of CD3(+)CD56(+) (natural T; NT) cells from peripheral blood mononuclear cells cultures. Conditioning with IL-15 also increased cytotoxic activity of lymphocytes against leukaemic target cells.

CONCLUSIONS

Although considerable evidence for cell-mediated immunity was shown for all liver allografts, the only clinical association was for IL-15 mRNA expression and graft acceptance. An in vitro model suggested that IL-15 may be enhancing the numbers and the activity of local regulatory cells, in particular resident NT cells in the liver, which may have a role in killing activated lymphocytes such as graft-reactive host T cells.

Management of primary sclerosing cholangitis

Guidelines for clinical practice are intended to indicate preferred approaches to medical problems as established by scientifically valid research. Double blind, placebo-controlled studies are preferable, but reports and expert review articles are also utilized in a thorough review of the literature conducted through the National Library of Medicine's MEDLINE. When only data that will not withstand objective scrutiny are available, a recommendation is identified as a consensus of experts. Guidelines are applicable to all physicians who address the subject, without regard to specialty training or interests, and are intended to indicate the preferable but not necessarily the only acceptable approach to a specific problem. Guidelines are intended to be flexible and must be distinguished from standards of care that are inflexible and rarely violated. Given the wide range of specifics in any health care problem, the physician must always choose the course best suited to the individual patient and the variables in existence at the moment of decision. Guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee and approved by the Board of Trustees. Each has been intensely reviewed and revised by the Committee, other experts in the field, physicians who will use them, and specialists in the science of decision of analysis. The recommendations of each guideline are therefore considered valid at the time of their production based on the data available. New developments in medical research and practice pertinent to each guideline will be reviewed at an established time and indicated at publication to assure continued validity.

Histologic and biochemical changes during the evolution of chronic rejection of liver allografts

Criteria for histologic diagnosis of chronic rejection (CR) are based on changes seen late in the disease process that are likely to be irreversible and unresponsive to treatment. Changes occurring during the evolution of CR are less clearly defined. The serial biopsy specimens, failed allografts, and biochemical profiles of 28 patients who underwent retransplantation for CR were examined with the aim of identifying histologic and biochemical features that were present during the early stages of CR. For each case, a point of acute deterioration in liver function tests (LFTs) was identified ("start time" [ST]) that subsequently progressed to graft failure. Biopsy specimens before, at the time of ("start biopsy" [SB]), and after the ST were assessed histologically, and findings were correlated with the biochemical changes. CR resulted from acute rejection (AR) that did not resolve. Centrilobular necroinflammation (CLNI) associated with an elevated aspartate transaminase (AST) level and portal tract features of AR were present at the start. Portal AR features resolved, CLNI persisted, AST level remained elevated, and bilirubin and alkaline phosphatase levels progressively increased throughout the evolution of CR. Portal tracts also showed a loss of small arterial and bile duct branches, with arterial loss occurring early and bile duct loss as a later progressive lesion. Foam cell arteriopathy was rarely seen in needle biopsy specimens. In conclusion, findings from this study may help identify patients at risk of progressing to graft loss from CR at a stage when the disease process is potentially reversible and amenable to treatment.

Mast cell hyperplasia in chronic rejection after liver transplantation

The pathogenesis of chronic hepatic allograft rejection is poorly understood. Recent studies suggested that hepatic mast cells may be involved in the pathogenesis of chronic cholestatic liver disease. Because chronic rejection after liver transplantation is predominantly a cholestatic process, the aim of this study is to determine whether hepatic mast cells are involved in its pathogenesis. Biopsy specimens from (1) normal livers (n = 5), (2) transplanted livers with end-stage chronic rejection (n = 8), and (3) transplanted livers with acute cellular rejection (mild, n = 7; moderate, n = 5; severe, n = 7) were studied. Biopsy specimens were stained immunohistochemically for mast cells with human antitryptase antibody. Mast cell density was significantly increased in the chronic-rejection group (4.9 +/- 0.6/mm2) compared with controls (2.9 +/- 0.5/mm2; P <.05). The percentage of portal tracts containing mast cells was significantly greater in chronic-rejection (89% +/- 8%) than control biopsy specimens (69% +/- 5%; P <.05), as was the average number of mast cells per portal tract (5.4 +/- 0.9 v 1.9 +/- 0.4 cells; P <.01). In chronic rejection, tissue mast cells frequently were seen surrounding damaged bile ducts in inflamed portal tracts. Neither mast cell density nor distribution was significantly different from controls in posttransplantation biopsy specimens with acute cellular rejection of mild, moderate, or severe degree. The finding of mast cells infiltrating portal tracts and surrounding damaged bile ducts in chronic rejection suggests that hepatic mast cells may be important effector cells in the pathogenesis of chronic rejection.

Primary Sclerosing Cholangitis

There is no proven medical therapy for primary sclerosing cholangitis. The goal of management should be treatment of symptoms and complications of cholestasis, as well as attempts at treating the underlying disease process. In addition, efforts should be made to recognize and treat or prevent the known complications of primary sclerosing cholangitis, such as fat-soluble vitamin deficiency, osteopenia, dominant biliary strictures, and cholangiocarcinoma. Although some medical therapy has been shown to improve serum liver test or histology results, there has been no effect on survival or time to liver transplantation. However, preliminary data on high-dosage ursodeoxycholic acid have been encouraging. Liver transplantation remains the only effective treatment and is recommended for patients with end-stage liver disease and symptomatic portal hypertension, liver failure, and recurrent or intractable bacterial cholangitis.

FK 506 rescue therapy for intractable liver allograft rejection

Intractable liver allograft rejection remains an important cause of graft loss. In this present study, we evaluated the role of oral FK 506 in 30 rejection episodes resistant to conventional cyclosporin-based triple immunosuppression in a series of 28 patients. Rejection was reversed in 11 (91.7%) of 12 patients for intractable acute rejection and in 10 (58.8%) of 17 patients for chronic rejection. A progressive decline in serum bilirubin was observed within 14 days in those successfully salvaged and a serum bilirubin of less than 200 micromol/l at the time of FK 506 conversion in the chronic rejection subgroup was found to be good predictor of response (specificity 100%, sensitivity 60%). New onset diabetes mellitus (29%) and reversible renal impairment (32%) were the commonest adverse events observed. Eleven (52%) of the responding patients successfully discontinued corticosteroid medication and are currently on FK 506 monotherapy. FK 506 therapy has a significant impact in the control of both intractable acute and chronic allograft rejection with an acceptable toxicity profile.

Cholestatic syndrome with bile duct damage and loss in renal transplant recipients with HCV infection

BACKGROUND/AIMS

Bile duct cells are known to be susceptible to hepatitis B and C virus, while it has been recently suggested that hepatitis B virus (HBV) and hepatitis C virus (HCV) infection may have a direct role in the pathogenesis of vanishing bile duct syndrome (VBDS) after liver transplantation. We report the development of a cholestatic syndrome associated with bile duct damage and loss in four HCV-infected renal transplant recipients.

METHODS

All four patients were followed up biochemically, serologically and with consecutive liver biopsies. Serum HCV RNA was quantitatively assessed and genotyping was performed.

RESULTS

Three patients were anti-HCV negative and one was anti-HCV/HBsAg positive at the time of transplantation and received the combination of methylprednisolone, azathioprine and cyclosporine A. Two patients became anti-HCV positive 1 year and one patient 3 years post-transplantation. Elevation of the cholestatic enzymes appeared simultaneously with seroconversion, or 2-4 years later, and was related to lesions of the small-sized interlobular bile ducts. Early bile duct lesions were characterized by degenerative changes of the epithelium. Late and more severe bile duct damage was associated with bile duct loss. The progression of the cholestatic syndrome coincided with high HCV RNA serum levels, while HCV genotype was 1a and 1b. Two patients (one with HBV co-infection) developed progressive VBDS and died of liver failure 2 and 3 years after biochemical onset. One patient, despite developing VBDS within a 10-month period, showed marked improvement of liver function after cessation of immunosuppression because of graft loss. The fourth patient, who had mild biochemical and histological bile duct changes, almost normalized liver function tests after withdrawal of azathioprine.

CONCLUSION

A progressive cholestatic syndrome due to bile duct damage and loss may develop in renal transplant patients with HCV infection. The occurrence of the lesions after the appearance of anti-HCV antibodies and the high HCV RNA levels are indicative of viral involvement in the pathogenesis. Withdrawal of immunosuppressive therapy may have a beneficial effect on the outcome of the disease.