Histopathology of early and late human hepatic allograft rejection: evidence of progressive destruction of interlobular bile ducts

Clinical Significance of Plasma Tenascin-C Levels in Recipients With Prolonged Jaundice After Living Donor Liver Transplantation

BACKGROUND

Focusing on tenascin-C (TNC), whose expression is enhanced during the tissue remodeling process, the present study aimed to clarify whether plasma TNC levels after living donor liver transplantation (LDLT) could be a predictor of irreversible liver damage in the recipients with prolonged jaundice (PJ).

METHODS

Among 123 adult recipients who underwent LDLT between March 2002 and December 2016, the subjects were 79 recipients in whom we could measure plasma TNC levels preoperatively (pre-) and on postoperative days 1 to 14 (POD1 to POD14). Prolonged jaundice was defined as serum total bilirubin level >10 mg/dL on POD14, and 79 recipients were divided into 2 groups: 56 in the non-PJ (NJ) group and 23 in the PJ group.

RESULTS

The PJ group had significantly increased pre-TNC; smaller grafts; decreased platelet counts POD14; increased TB-POD1, -POD7, and -POD14; increased prothrombin time-international normalized ratio on POD7 and POD14; and higher 90-day mortality than the NJ group. As for the risk factors for 90-day mortality, multivariate analysis identified TNC-POD14 as a single significant independent prognostic factor (P = .015). The best cut-off value of TNC-POD14 for 90-day survival was determined to be 193.7 ng/mL. In the PJ group, the patients with low TNC-POD14 (<193.7 ng/mL) had satisfactory survival, with 100.0 % at 90 days, while the patients with high TNC-POD14 (≥193.7 ng/mL) had significantly poor survival, with 38.5 % at 90 days (P = .004).

CONCLUSIONS

In PJ after LDLT, plasma TNC-POD14 is very useful for diagnosing postoperative irreversible liver damage early.

Molecular Mechanisms of Ischaemia-Reperfusion Injury and Regeneration in the Liver-Shock and Surgery-Associated Changes

Hepatic ischemia-reperfusion injury (IRI) represents a major challenge during liver surgery, liver preservation for transplantation, and can cause hemorrhagic shock with severe hypoxemia and trauma. The reduction of blood supply with a concomitant deficit in oxygen delivery initiates various molecular mechanisms involving the innate and adaptive immune response, alterations in gene transcription, induction of cell death programs, and changes in metabolic state and vascular function. Hepatic IRI is a major cause of morbidity and mortality, and is associated with an increased risk for tumor growth and recurrence after oncologic surgery for primary and secondary hepatobiliary malignancies. Therapeutic strategies to prevent or treat hepatic IRI have been investigated in animal models but, for the most part, have failed to provide a protective effect in a clinical setting. This review focuses on the molecular mechanisms underlying hepatic IRI and regeneration, as well as its clinical implications. A better understanding of this complex and highly dynamic process may allow for the development of innovative therapeutic approaches and optimize patient outcomes.

Stability Analysis of Geotechnical Landslide Based on GA-BP Neural Network Model

Rock and soil landslides, a regular geological disaster in engineering construction, endanger national property and, in severe circumstances, result in a huge number of casualties. A set of methods for landslide stability analysis and prediction has been established, with the academic idea of "geological process mechanism analysis-quantitative evaluation" at its core, combined with detailed field investigation of geological hazards, forming a relatively complete technical route for research on landslide stability analysis. The work of this paper can be summarized as follows: (1) Introduce the research status of geotechnical landslide stability at home and abroad and the current development trend of neural network. (2) Through the collected sample database, take the training function and the number of hidden layer neurons as variables to optimize the BP neural network, and combine the optimized BP neural network with the genetic algorithm to construct the GA-BP neural network. (3) The stability coefficients of the BP neural network, the genetic algorithm based back propagation neural network (GA-BPNN), and the limit equilibrium technique are analyzed and compared. The findings imply that landslide stability can be assessed using neural networks. GA-BPNN is a viable alternative to back propagation neural network (BPNN). The algorithm is more accurate, has a faster convergence rate, and is more stable.

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.

Estrogen-Estrogen Receptor α Signaling Facilitates Bilirubin Metabolism in Regenerating Liver Through Regulating Cytochrome P450 2A6 Expression

BACKGROUND

After living donor liver transplantation (LDLT), rising serum bilirubin levels commonly indicate insufficient numbers of hepatocytes are available to metabolize bilirubin into biliverdin. Recovery of bilirubin levels is an important marker of hepatocyte repopulation after LDLT. Cytochrome P450 (CYP) 2A6 in humans (or cyp2a4 in rodents) can function as "bilirubin oxidase." Functional hepatocytes contain abundant CYP2A6, which is considered a marker for hepatocyte function recovery. The aim of our study was to determine the impact of estradiol/estrogen receptor signaling on bilirubin levels during liver function recovery.

METHODS

We conducted a hospital-based cohort study of bilirubin levels after LDLT surgery in both liver graft donors and recipients, performed a transcriptome comparison of wild-type versus estrogen receptor (ER)α knockout mice and a bioinformatics analysis of transcriptome changes in their regenerating liver after two-third partial hepatectomy (PHx), and assayed in vitro expression of cytochrome (CYP2A6) in human hepatic progenitor cells (HepRG) treated with 17β-estradiol (E2).

RESULTS

The latency of bilirubin level reduction was shorter in women than in men, suggesting that a female factor promotes bilirubin recovery after liver transplantation surgery. In the PHx mouse model, the expression of the cyp2a4 gene was significantly lower in livers from the knockout ERα mice than in livers from their wild-type littermates; but the expression of other bilirubin metabolism-related genes were similar between these groups. Moreover, E2 or bilirubin treatments significantly promoted CYP2A6 expression in hepatocyte progenitor cells (HepRG cells). Sequence analysis revealed similar levels of aryl hydrocarbon receptor (AhR; bilirubin responsive nuclear receptor) and ESR1 binding to the promoter region of CYP2A6.

CONCLUSIONS

This is the first report to demonstrate, on a molecular level, that E2/ERα signaling facilitates bilirubin metabolism in regenerating liver. Our findings contribute new knowledge to our understanding of why the latency of improved bilirubin metabolism and thereby liver function recovery is shorter in females than in males.

Penis Allotransplantation in Beagle Dog

This is an original research of penis allotransplantation. The paper presents an experiment allogenic penis transplantation model in Beagles, with a focus on recovery of blood supply and changes in tissue architecture. Twenty adult Beagles were allocated to 10 pairs for penile transplantation. After operation, the skin and glans were observed. If adverse symptoms occurred, the transplanted penis was resected and pathologically examined. Frequency of urination, urinary stream, and patency level were recorded 7 days after transplantation. Cystourethrography was performed on Day 10. The transplanted penises were resected on Day 14 for pathological examination. The research showed that transplanted penises survived after allotransplantation, and the dogs regained urination ability. Penis autotransplantation in Beagles is feasible. This preliminary study shows a potential for application of this new procedure for penis transplantation in humans.

From immunosuppression to tolerance

The past three decades have seen liver transplantation becoming a major therapeutic approach in the management of end-stage liver diseases. This is due to the dramatic improvement in survival after liver transplantation as a consequence of the improvement of surgical and anaesthetic techniques, of post-transplant medico-surgical management and of prevention of disease recurrence and other post-transplant complications. Improved use of post-transplant immunosuppression to prevent acute and chronic rejection is a major factor in these improved results. The liver has been shown to be more tolerogenic than other organs, and matching of donor and recipients is mainly limited to ABO blood group compatibility. However, long-term immunosuppression is required to avoid severe acute and chronic rejection and graft loss. With the current immunosuppression protocols, the risk of acute rejection requiring additional therapy is 10-40% and the risk of chronic rejection is below 5%. However, the development of histological lesions in the graft in long-term survivors suggest atypical forms of graft rejection may develop as a consequence of under-immunosuppression. The backbone of immunosuppression remains calcineurin inhibitors (CNI) mostly in association with steroids in the short-term and mycophenolate mofetil or mTOR inhibitors (everolimus). The occurrence of post-transplant complications related to the immunosuppressive therapy has led to the development of new protocols aimed at protecting renal function and preventing the development of de novo cancer and of dysmetabolic syndrome. However, there is no new class of immunosuppressive drugs in the pipeline able to replace current protocols in the near future. The aim of a full immune tolerance of the graft is rarely achieved since only 20% of selected patients can be weaned successfully off immunosuppression. In the future, immunosuppression will probably be more case oriented aiming to protect the graft from rejection and at reducing the risk of disease recurrence and complications related to immunosuppressive therapy. Such approaches will include strategies aiming to promote stable long-term immunological tolerance of the liver graft.

Functional role of cellular senescence in biliary injury

Cellular senescence is a state of irreversible cell cycle arrest that has been involved in many gastrointestinal diseases, including human cholestatic liver disorders. Senescence may play a role in biliary atresia, primary sclerosing cholangitis, cellular rejection, and primary biliary cirrhosis, four liver diseases affecting cholangiocytes and the biliary system. In this review, we examine proposed mechanisms of senescence-related biliary diseases, including hypotheses associated with the senescence-associated phenotype, induction of senescence in nearby cells, and the depletion of stem cell subpopulations. Current evidence for the molecular mechanisms of senescence in the previously mentioned diseases is discussed in detail, with attention to recent advances on the role of pathways associated with senescence-associated phenotype, stress-induced senescence, telomere dysfunction, and autophagy.

Erratum: Differential expressed genes in ECV304 Endothelial-like Cells infected with Human Cytomegalovirus

BACKGROUND

Human cytomegalovirus (HCMV) is a virus which has the potential to alter cellular gene expression through multiple mechanisms.

OBJECTIVE

With the application of DNA microarrays, we could monitor the effects of pathogens on host-cell gene expression programmes in great depth and on a broad scale.

METHODS

Changes in mRNA expression levels of human endothelial-like ECV304 cells following infection with human cytomegalovirus AD169 strain was analyzed by a microarray system comprising 21073 60-mer oligonucleotide probes which represent 18716 human genes or transcripts.

RESULTS

The results from cDNA microarray showed that there were 559 differential expressed genes consisted of 471 upregulated genes and 88 down-regulated genes. Real-time qPCR was performed to validate the expression of 6 selected genes (RPS24, MGC8721, SLC27A3, MST4, TRAF2 and LRRC28), and the results of which were consistent with those from the microarray. Among 237 biology processes, 39 biology processes were found to be related significantly to HCMV-infection. The signal transduction is the most significant biological process with the lowest p value (p=0.005) among all biological process which involved in response to HCMV infection.

CONCLUSION

Several of these gene products might play key roles in virus-induced pathogenesis. These findings may help to elucidate the pathogenic mechanisms of HCMV caused diseases. [This corrects the article on p. 243 in vol. 13, PMID: 24235919.].

Global analysis of differential expressed genes in ECV304 Endothelial-like cells infected with human cytomegalovirus

BACKGROUND

Human cytomegalovirus (HCMV) is a virus which has the potential to alter cellular gene expression through multiple mechanisms.

OBJECTIVE

With the application of DNA microarrays, we could monitor the effects of pathogens on host-cell gene expression programmes in great depth and on a broad scale.

METHODS

Changes in mRNA expression levels of human endothelial-like ECV304 cells following infection with human cytomegalovirus AD169 strain was analyzed by a microarray system comprising 21073 60-mer oligonucleotide probes which represent 18716 human genes or transcripts.

RESULTS

The results from cDNA microarray showed that there were 559 differential expressed genes consisted of 471 upregulated genes and 88 down-regulated genes. Real-time qPCR was performed to validate the expression of 6 selected genes (RPS24, MGC8721, SLC27A3, MST4, TRAF2 and LRRC28), and the results of which were consistent with those from the microarray. Among 237 biology processes, 39 biology processes were found to be related significantly to HCMV-infection. The signal transduction is the most significant biological process with the lowest p value (p=0.005) among all biological process which involved in response to HCMV infection.

CONCLUSION

Several of these gene products might play key roles in virus-induced pathogenesis. These findings may help to elucidate the pathogenic mechanisms of HCMV caused diseases.

Ischemia-Reperfusion Injury and Ischemic-Type Biliary Lesions following Liver Transplantation

Ischemia-reperfusion (I-R) injury after liver transplantation (LT) induces intra- and/or extrahepatic nonanastomotic ischemic-type biliary lesions (ITBLs). Subsequent bile duct stricture is a significant cause of morbidity and even mortality in patients who underwent LT. Although the pathogenesis of ITBLs is multifactorial, there are three main interconnected mechanisms responsible for their formation: cold and warm I-R injury, injury induced by cytotoxic bile salts, and immunological-mediated injury. Cold and warm ischemic insult can induce direct injury to the cholangiocytes and/or damage to the arterioles of the peribiliary vascular plexus, which in turn leads to apoptosis and necrosis of the cholangiocytes. Liver grafts from suboptimal or extended-criteria donors are more susceptible to cold and warm I-R injury and develop more easily ITBLs than normal livers. This paper, focusing on liver I-R injury, reviews the risk factors and mechanisms leading to ITBLs following LT.

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.

Intrahepatic cholestasis after liver transplantation

Biochemical cholestasis after liver transplantation is common and often has no clinical significance if biliary anastomosis strictures and leaks have been excluded. There is no agreed upon definition for severe cholestasis, but it is associated with a worse mortality. There has been little evaluation on risk factors, but these include cryoprecipitate and platelet transfusion intraoperatively, nonidentical blood group, suboptimal graft appearance, inpatient status before transplant, and bacteremia within the first month. Associated causes considered as early (<6 months) include ischemia-reperfusion injury, primary nonfunction, small-for-size graft syndrome, infection, drugs and acute cellular rejection. Late causes include hepatic artery thrombosis, chronic rejection, biliary complications, recurrent viral and cholestatic disease, and posttransplant lymphoproliferative disorder.

Postoperative hyperbilirubinemia and graft outcome in living donor liver transplantation

Little information is available on the characteristics and clinical significance of serum bilirubin level early after liver transplantation. The aim of this study was to clarify the risk factors for early graft loss and to assess the significance of postoperative hyperbilirubinemia as a predictor of graft outcome in living donor liver transplantation (LDLT). We retrospectively analyzed perioperative parameters in 68 patients who underwent LDLT. Graft loss within 1 year post-LDLT was confirmed in 9 patients (13.4%). Univariate analysis of risk factors showed that preoperative Model for End-Stage Liver Disease score, donor age, postoperative peak serum bilirubin level (p-BIL) within 28 days after LDLT, and surgical complications were significant determinants of early graft loss (<1 year post-transplant). Multivariate analysis identified p-BIL (odds ratio = 1.170, 95% confidence interval = 1.030-1.329, P = 0.016) as the only independent predictor of early graft loss. The incidence of such loss was high in patients with p-BIL over 27.0 mg/dL (area under the receiver operating characteristic curve = 0.988). In conclusion, serum bilirubin level is a useful predictor of short-term (<1 year) graft outcome and for considering retransplantation in a timely fashion.

Distinguishing between recurrent primary sclerosing cholangitis and chronic rejection

1. Recurrent primary sclerosing cholangitis (PSC) is extremely difficult, if not impossible, to distinguish from other causes of biliary strictures or sclerosing cholangitis in allografts using needle biopsy evaluation alone. Technical problems with biliary reconstruction, long cold ischemic times, non-heart beating donors, ABO blood group incompatibility, antibody-mediated rejection, and small-for-size syndrome in reduced-size or living donor livers can also cause similar manifestations in a peripheral core biopsy. 2. Some difficulties in distinguishing between sclerosing cholangitis and chronic rejection (CR) arise because: a) at risk populations are similar; b) both can cause "cholestatic" elevation of liver injury tests; and c) both can lead to intrahepatic cholestasis and small bile duct loss. 3. Etiopathogenesis and pathology of CR and sclerosing cholangitis have some overlapping features, but show distinct differences that result in significantly different and discriminating pathologic manifestations. 4. Clues in the clinical history, evaluation of serial biopsies, and histopathology can be used to distinguish with confidence between sclerosing cholangitis and CR. 5. Potential discriminating features include liver size and gross appearance, and histopathology findings in the arterial tree, hilar lymph nodes, large and small bile ducts, interface zone, lobular, and perivenular regions.

Incidence and risk factors for the development of prolonged and severe intrahepatic cholestasis after liver transplantation

Predictive factors for intrahepatic cholestasis after orthotopic liver transplantation (OLT) have not yet been established. We sought to identify the incidence and risk factors associated with prolonged severe intrahepatic cholestasis (PSIC) after OLT. We assessed 428 consecutive patients undergoing their first OLT. PSIC was diagnosed if a serum bilirubin concentration was greater than 100 micromol/L and/or a 3-fold increase of alkaline phosphatase occurred within the first month after OLT and was sustained for at least 1 week in the absence of biliary complications. Multivariable logistic regression identified factors independently associated with PSIC. PSIC developed in 107 patients (25%). Independent risk factors by multivariable analysis were intraoperative transfusion of cryoprecipitate and platelets; nonidentical blood group status; suboptimal organ appearance; inpatient status before transplantation; and bacteraemia in the first month after transplantation. In contrast, acute liver failure, older age, and higher levels of serum sodium and serum potassium were all associated with a reduced likelihood of developing PSIC in the first month. There were 47 deaths in the PSIC group (44%) as opposed to 65 deaths in the non-PSIC group (20%) after OLT. A poor preoperative clinical status in conjunction with a suboptimal graft was associated with PSIC after OLT. Avoidance of suboptimal livers and ABO nonidentical grafts for young patients with poor synthetic function and for pretransplant inpatients may lessen this complication and reduce the associated early mortality.

The role of TNF in hepatic histopathological manifestations and hepatic CD8+ T cell alloresponses in murine MHC class I disparate GVHD

Transfer of B6 T cells to major histocompatibility complex (MHC) class I disparate bm1 x B6 F1 mice leads to the development of hepatic graft-versus-host disease (GVHD) characterized by an active hepatitis with portal and lobular inflammation as well as bile duct inflammation and venulitis. The present studies determined the role of tumor necrosis factor (TNF) in hepatic GVHD. B6 responder cells were cultured with irradiated MHC class I disparate bm1 or syngeneic spleen cells (SpC) in the presence or absence of TNF receptor inhibitor [TNFR-immunoglobulin (Ig)]. Recipient bm1 x B6 F1 mice were irradiated (600 cGy) and reconstituted with 5 x 10(6) T cell-depleted B6 bone marrow cells and 1 x 10(7) B6 SpC. Mice were injected with an adenovirus encoding TNFR-Ig [TNF inhibitor-encoding adenovirus (Adv-TNFi)] or beta-galactosidase (Adv-betagal). Severity of liver GVHD was assessed by a composite histopathological score consisting of the sum of scores for venulitis, lobular hepatitis, and bile duct inflammation. Addition of TNFR-Ig reduced cell proliferation in mixed lymphocyte cultures using B6 responder SpC by 71% +/- 12.8% and interferon-gamma responses by 78% +/- 18%. GVHD-induced "wasting disease" was reduced in Adv-TNFi recipients [4.4%+/-5.2% weight loss (n=11)] compared with Adv-betagal recipients [16.1%+/-7.6% weight loss (n=11; P=0.0004)] 9 days post-transplant. Composite histopathological scores and individual venulitis scores were reduced with the addition of Adv-TNFi. Hepatic CD8+ T cells in the recipients of Adv-TNFi were reduced as compared with recipients of Adv-betagal. In conclusion, Adv-TNFi reduces MHC class I disparate alloproliferative responses and hepatic GVHD.

Four-year follow-up of a prospective randomized trial of mycophenolate mofetil with cyclosporine microemulsion or tacrolimus following liver transplantation

BACKGROUND

This is a 4-yr follow-up of a trial using mycophenolate mofetil (MMF) induction in orthotopic liver transplantation (OLT). The goal of this study was to evaluate a multidrug approach that would reduce both early and long-term morbidity related to immunosuppression while maintaining an acceptable freedom from rejection.

METHODS

This was a prospective, randomized, intent to treat study designed to compare the primary endpoints of rejection and infection, and secondary endpoints of liver function, renal function, bone marrow function, cardiovascular risk factors, and the recurrence of hepatitis C. Ninety-nine consecutive patients with end stage liver disease who underwent OLT were randomized to receive either cyclosporine microemulsion (N) (50 patients) or tacrolimus (FK) (49 patients) starting on postoperative day 2, with MMF and an identical steroid taper begun preoperatively.

RESULTS

Ninety of 99 patients (N 46, FK 44) completed the 4-yr follow-up. The overall 4-yr patient and graft survivals were 93 and 89%, respectively. There was no significant difference in 4-yr patient (N 96% vs. FK 90%, p = ns) or graft (N, 90% vs. FK, 88%, p = ns) survival between groups. The 4-yr rejection rate was not significantly different in either arm (N = 34%, FK = 24%; p = 0.28). There were no differences in infection rates in either arm. The patients with hepatitis C had no differences in the viral titers or Knodell biopsy scores between groups. However, in the hepatitis C subgroup (37 patients), the FK patients had a significantly lower rejection rate (p = 0.0097) and a significantly lower clinically recurrent hepatitis C rate (p = 0.05) than the N patients. No difference was seen in the percent of patients weaned off of steroids after 4 yr (N 51%, FK 49%). There were no differences in the incidences of diabetes mellitus and hypertension. When renal dysfunction was analyzed, a significant difference in the number of patients whose creatinine had increased twofold since transplant was seen (N 63%, FK 38%, p = 0.04).

CONCLUSIONS

Use of MMF induction and maintenance following OLT in conjunction with either N or FK and an identical steroid taper, resulted in an acceptable long-term incidence of rejection and infection, without an increase in long-term graft or patient morbidity.

Are preformed antibodies to biliary epithelial cells of clinical importance in liver transplantation?

During acute liver allograft rejection, most of the tissue damage to bile duct epithelium is thought to occur as a consequence of direct immunologic injury by T-cell-mediated immune effector mechanisms. However, the role of antibodies to biliary epithelial cells (BECs) in liver transplant rejection is not known. We therefore investigated cross-match sera obtained immediately before liver transplantation from 95 patients for the presence of BEC-reactive antibodies to determine their association with acute rejection. BECs were isolated from one normal healthy liver. Antibody binding was detected by using flow cytometric analysis. Donor lymphocyte-specific cross-matches using complement-dependent cytotoxicity (CDC) and flow cytometric assays also were performed. The 2-year patient survival rate in this study was 86.3%. Eleven patients were positive for either CDC or flow cytometric cross-matches. BEC antibodies were detected in 41 serum samples (43.2%). Patients with BEC antibodies experienced acute rejection more frequently (65.9%) compared with 42.5% without antibodies (P <.03). HLA specificity determinations indicated that in 5 of 41 cases, anti-BEC reactivity was caused by HLA antibodies. No correlations between the presence of BEC antibodies and patient survival and the occurrence of cholangitis and nonsurgical bile duct strictures were found within 2 years of follow-up. In conclusion, preformed antibodies to BECs are associated with acute rejection. Thus, the presence of these antibodies before transplantation may facilitate acute liver graft rejection.

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.

Overview of pediatric liver transplantation

Liver transplantation is a successful and useful therapy for children with chronic or end-stage liver disease and those with a variety of extrahepatic metabolic diseases that can be corrected by liver replacement. Major developments in medical management, donor availability and procurement, operative techniques, and post-operative management all contributed to the dramatic improvement in outcome and growth of liver transplantation from its inception in 1963 [1,7,21]. The excellent long-term outcomes that have been achieved are the product of the coordinated efforts of liver transplant surgeons, specialists in pediatric hepatology and other medical areas, nurses, local practitioners, and the patients and their families. Future advances in transplant immunobiology, organ availability and infection control are likely to lead to still greater improvements in short and long-term outcome [34].

The human cytomegalovirus

Human cytomegalovirus (HCMV), a betaherpesvirus, represents the major infectious cause of birth defects, as well as an important pathogen for immunocompromised individuals. The viral nucleocapsid containing a linear double-stranded DNA of 230 kb is surrounded by a proteinaceous tegument, which is itself enclosed by a loosely applied lipid bilayer. Expression of the HCMV genome is controlled by a cascade of transcriptional events that leads to the synthesis of three categories of viral proteins designated as immediate-early, early, and late. Clinical manifestations can be seen following primary infection, reinfection, or reactivation. About 10% of infants are infected by the age of 6 months following transmission from their mothers via the placenta, during delivery, or by breastfeeding. HCMV is a significant post-allograft pathogen and contributes to graft loss independently from graft rejection. Histopathologic examination of necropsy tissues demonstrates that the virus enters via the epithelium of the upper alimentary, respiratory, or genitourinary tracts. Hematogenous spreading is typically followed by infection of ductal epithelial cells. Infections are kept under control by the immune system. However, total HCMV clearance is rarely achieved, and the viral genome remains at selected sites in a latent state. Virological and molecular detection of HCMV, as well as serological demonstration of a specific immune response, are used for diagnosis. Treatment of HCMV infections is difficult because there are few options. The presently available drugs produced a significant clinical improvement, but suffer from poor oral bioavailability, low potency, development of resistance in clinical practice, and dose-limiting toxicities.

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

BACKGROUND

The Banff schema is the internationally accepted standard for grading acute liver-allograft rejection, but it has not been prospectively tested.

METHODS

Complete Banff grading was prospectively applied to 2,038 liver-allograft biopsies from 901 adult tacrolimus-treated primary hepatic allograft recipients between August 1995 and September 2001. Histopathologic data was melded with demographic, clinical, and laboratory data into a database on an ongoing basis using locally developed software.

RESULTS

Acute rejection developed in 575 of 901 (64%) patients and the worst grade was mild in 422 of 575 (73%). At least one episode of moderate or severe acute rejection developed in 153 of 901 (17%) patients and most episodes, irrespective of severity, occurred within the first year after transplantation. Patients with moderate or severe acute rejection showed higher alanine aminotransferase (P =0.007) and aspartate aminotransferase ( P=0.07) levels and were more likely to develop perivenular fibrosis on follow-up biopsies (P =0.001) and graft failure from acute or chronic rejection ( P=0.004) than those with mild rejection. Regardless of severity, 80% of patients with acute rejection did not develop significant fibrosis in follow-up biopsies, and graft failure from acute or chronic rejection occurred in only 11 of 901 (1%) allografts.

CONCLUSIONS

Most acute-rejection episodes are mild and do not lead to clinically significant architectural sequelae. When tested prospectively under real-life and -time conditions, the Banff schema can be used to identify those few patients who are potentially at risk for more significant problems. Creation, capture, and integration of non-free text, or "digital," pathology data can be used to prospectively conduct outcomes-based research in transplantation.

A prospective randomized trial of mycophenolate mofetil with neoral or tacrolimus after orthotopic liver transplantation

BACKGROUND

The success of liver transplantation in this decade has become the stimulus to extend the donor and recipient pool. Reducing early posttransplant morbidity to maintain our success, as we expand our frontiers, has led us to focus on balanced testing of multidrug immunosuppression regimens.

METHODS

A prospective trial in orthotopic liver transplantation using Mycophenolate Mofetil and an identical steroid taper with randomization of patients to Neoral (N) or Tacrolimus (FK) is the basis of this report. This was an intent-to-treat study designed to compare the 6-month primary endpoints of rejection and infection and to compare the 6-month secondary endpoints of liver function, renal function, bone marrow function, hypertension, and serum cholesterol levels.

RESULTS

Ninety-seven patients completed the 6-month follow-up period (N=49, FK=48). The actual 6-month patient and graft survival rates were 98% and 94%, respectively. There was no difference in the number of patients with rejection episodes (N=11, FK=8) (P=0.61). There were 24 infections (3 cytomegalovirus) in the FK group and 30 infections (9 cytomegalovirus) in the N group. The cholesterol levels at 6 months were not significantly different (P=0.07) between the groups. The other secondary 6-month endpoints were not significantly different, except total bilirubin, which was lower in the FK arm (P=0.02).

CONCLUSIONS

The use of Mycophenolate Mofetil with N or FK and an identical steroid taper after orthotopic liver transplantation is associated with excellent graft and patient survival, and at 6 months, only 191% of the patients experienced rejection, with a 48% overall infection rate.

High incidence of antitissue antibodies in patients experiencing chronic liver allograft rejection

BACKGROUND

The precise immunologic mechanisms responsible for chronic rejection of liver allografts are unknown. We have recently shown in a rodent model that recipients of liver allografts developed non-major histocompatibility complex antitissue antibodies. The aim of the present study was to test this hypothesis in the clinical setting.

METHODS

Posttransplant sera of 14 patients undergoing chronic rejection and of 48 control patients (12 liver transplant patients with chronic active hepatitis or liver cirrhosis related to hepatitis C virus [HCV] infection and without chronic rejection, 10 with sclerosing cholangitis, and 26 with normal liver function tests and liver biopsy) were tested for the presence of antitissue antibodies by indirect immunofluorescence. Pretransplant sera of all these patients lacked antitissue antibodies.

RESULTS

Antitissue antibodies were detected in 71% of patients who developed chronic rejection (before or at the time of chronic rejection). This incidence was significantly greater than that observed in patients not undergoing rejection (HCV-related chronic active hepatitis, 16%; sclerosing cholangitis, 0%; normal liver biopsy, 7%). All these autoantibodies were directed against the smooth muscle and/or the nucleus. In two patients, anti-smooth muscle antibodies had an antiactin or antivimentin specificity.

CONCLUSIONS

These results show a strong association between chronic allograft rejection and the development of antitissue antibodies and suggest that these antibodies could be used to identify patients at high risk of developing chronic rejection after liver transplantation.

Immune cholangitis: liver allograft rejection and graft-versus-host disease

A pronounced similarity exists between liver allograft rejection and graft-versus-host disease (GVHD) in the damage and eventual destruction of small intrahepatic bile ducts. Although an immunologic reaction has an important role, precisely identifying the target antigens or reason for persistence of the immune response has been difficult. An important difference between GVHD and liver rejection is the development of obliterative arteriopathy only in rejection. The three main histopathologic features of acute rejection are a predominantly mononuclear but mixed portal inflammation, subendothelial inflammation of portal or terminal hepatic veins (or both), and bile duct inflammation and damage. In acute rejection, a controversial issue is determining when therapeutic intervention is needed. The recommended approach is to base treatment on a combination of histopathologic changes and liver injury or dysfunction. Chronic rejection, which usually does not occur before 2 months after transplantation, is characterized by two main histopathologic features: (1) damage and loss of small bile ducts and (2) obliterative arteriopathy. Acute GVHD begins within the first month after transplantation and most commonly involves the skin, gastrointestinal tract, and liver, whereas chronic GVHD usually develops more than 80 to 100 days after liver transplantation and affects 30 to 50% of long-term survivors. Recognition of the early, cellular stages of chronic GVHD is important in preventing irreversible damage.

Cytomegalovirus infection is associated with increased inflammation and severe bile duct damage in rat liver allografts

It has been suggested that cytomegalovirus (CMV) infection is involved in allograft rejection. In liver transplantation, it has been suggested that CMV is associated with the development of vanishing bile duct syndrome (VBDS), and persistent CMV has been found in liver grafts that develop chronic rejection. In this experimental study, the effect of rat CMV (RCMV) infection on intragraft changes was investigated in a rat model of acute liver allograft rejection. Liver transplantations were performed in a rat strain combination of PVG (RT1c) --> BN (RT1n). No immunosuppression was given. One group of animals was infected with RCMV Maastricht Strain (10(5) plaque-forming units, intraperitoneally), and another group was left uninfected. The grafts were examined histologically after the rats were killed on postoperative days 7 through 9 at the early phase and days 20 through 30 at the late phase of rejection. Immunohistochemical studies were performed to demonstrate the immunological activation markers major histocompatibility complex class II and interleukin 2 receptors, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), and their ligands. RCMV infection was demonstrated from the grafts by culture and direct antigen detection. In liver allografts undergoing acute rejection, CMV significantly increased portal inflammation and caused more severe bile duct damage than in the uninfected grafts. CMV was also linked to the induction of VCAM-1 in the endothelial cells. The ongoing infection was found to vary over time in the different structures of the liver grafts, including the vascular endothelium and bile ducts. Our results support an association between CMV infection and the immunological mechanisms of rejection, as well as the role of CMV in the development of bile duct damage in liver allografts.

Expression of the membrane attack complex of complement and its inhibitors during human liver allograft transplantation

BACKGROUND/AIMS

In order to test the possible role of activated complement in human liver allograft rejection, we evaluated the expression of the membrane attack complex of complement, its soluble inhibitors clusterin and vitronectin and its membrane inhibitor protectin during the evolution of liver transplants.

METHODS

An indirect immunoperoxidase technique was applied to biopsy specimens obtained from liver allografts in 16 patients without complications, nine with acute rejection, four with chronic rejection and five with biliary complications.

RESULTS

Two types of membrane attack complex deposition were observed: (a) extracellular deposits in portal tracts and perisinusoidal matrix, associated with clusterin and vitronectin, similar to those found in the normal liver; and (b) intra-portal vascular deposits, devoid of clusterin and vitronectin. Vascular membrane attack complex deposition was detected in four clinically stable patients, three patients with chronic rejection and two patients with biliary complications. In clinically stable patients, vascular membrane attack complex deposition was restricted to large portal vessels and was detected in a minority of portal tracts. In patients with chronic rejection or biliary complications, vascular membrane attack complex deposition was detected along both large and small portal vessels and was present in the majority of portal tracts. Protectin induction on hepatocytes was detected in 33 cases.

CONCLUSIONS

Our results suggest that membrane attack complex deposition is unlikely to play a major role in the pathogenesis of acute liver allograft rejection but may contribute to the vascular and biliary lesions observed in chronic rejection.

Efficacy of tacrolimus as rescue therapy for chronic rejection in orthotopic liver transplantation: a report of the U.S. Multicenter Liver Study Group

BACKGROUND

A study was performed by 17 different U.S. liver transplantation centers to determine the safety and efficacy of conversion from cyclosporine to tacrolimus for chronic allograft rejection.

METHODS

Ninety-one patients were converted to tacrolimus a mean of 319 days after liver transplantation. The indication for conversion was ongoing chronic rejection confirmed by biochemical and histologic criteria. Patients were followed for a mean of 251 days until the end of the study.

RESULTS

Sixty-four patients (70.3%) were alive with their initial hepatic allograft at the conclusion of the study period and were defined as the responder group. Twenty-seven patients (29.7%) failed to respond to treatment, and 20 of them required a second liver graft. The actuarial graft survival for the total patient group was 69.9% and 48.5% at 1 and 2 years, respectively. The actuarial patient survival at 1 and 2 years was 84.4% and 81.2%, respectively. Two significant positive prognostic factors were identified. Patients with a total bilirubin of < or = 10 mg/dl at the time of conversion had a significantly better graft and patient survival than patients converted with a total bilirubin > 10 mg/dl (P=0.00002 and P=0.00125, respectively). The time between liver transplantation and conversion also affected graft and patient survival. Patients converted to tacrolimus < or = 90 days after transplantation had a 1-year actuarial graft and patient survival of 51.9% and 65.9%, respectively, compared with 73.2% and 87.7% for those converted > 90 days after transplantation. The mean total bilirubin level for the responder group was 7.1 mg/dl at the time of conversion and decreased significantly to a mean of 3.4 mg/dl at the end of the study (P=0.0018). Thirteen patients (14.3%) died during the study. Sepsis was the major contributing cause of death in most of these patients.

CONCLUSIONS

Our results suggest that conversion to tacrolimus for chronic rejection after orthotopic liver transplantation represents an effective therapeutic option. Conversion to tacrolimus before development of elevated total bilirubin levels showed a significant impact on long-term outcome.

Patterns of intermediate filaments, VLA integrins and HLA antigens in a new human biliary epithelial cell line sensitive to interferon-gamma

BACKGROUND/AIMS

Intra-hepatic bile ducts are the primary site of damage in several immunologically mediated liver diseases. However, immunological processes underlying biliary epithelial cell recognition by T lymphocytes are poorly understood. Therefore, a convenient in vitro model that could mimic these immunologic disorders would be of great interest.

METHODS

A human cell line (HuGB) was established from a metastasis of gallbladder adenocarcinoma in the liver. Intermediate filament expression was analysed by immunostaining, and gamma-glutamyl transpeptidase and albumin secretion were measured. VLA integrin expression pattern, expression of HLA class I and II antigens and ICAM-1 protein were analysed by flow cytometry and their modulation by interferon-gamma was quantitated using a QIFIKIT commercial kit.

RESULTS

Histological analysis showed high similarity between the initial gallbladder adenocarcinoma and the established cell line. Cytokeratins 8 and 19 and vimentin showed strong positive staining in the established cell line. Gamma-glutamyl transpeptidase was secreted by these cells while albumin expression was negative. HuGB cells also expressed VLA-alpha2, VLA-alpha3, VLA-alpha6, VLA-beta1, but not VLA-alpha1, VLA-alpha4 and NCAM, a pattern of adhesion molecule expression compatible with the biliary epithelium. Also, similar to the biliary epithelium found in normal liver, HuGB cells expressed abundant HLA class I but few HLA class II antigens. We found that the expression of HLA antigens and ICAM-1 protein were increased during interferon-gamma treatment of HuGB cell line.

CONCLUSIONS

Both phenotypic and morphological characteristics of HuGB cells suggested their biliary origin. Sensitivity of HuGB cells to interferon-gamma suggests that this new cell line could represent a suitable model to investigate the up-regulation of membrane antigens occurring in immune diseases involving biliary epithelial cells.

Persistent cytomegalovirus in liver allografts with chronic rejection

Cytomegalovirus (CMV) infection is one of the suggested risk factors for chronic allograft rejection. Clinical and experimental studies have shown that CMV is somehow implicated in rejection mechanisms and in the generation of graft arteriosclerosis, characteristic of chronic rejection. In liver transplantation, there is also evidence of an association between CMV and vanishing bile duct-syndrome (VBDS), which is characteristic of chronic liver allograft rejection. In this study, the role of posttransplant CMV infection and of acute rejection in the patients with irreversible, histologically confirmed chronic liver rejection with VBDS and vasculopathy was analyzed. Ten of 200 (5%) consecutive liver transplants were lost due to chronic rejection, from between 5 and 28 months from transplantation. In these 10 patients, acute rejections were frequent, and nine of ten patients had at least one episode of rejection early after transplantation. All patients (10 of 10) had a history of CMV infection usually following acute rejection. To investigate the role of CMV in chronic rejection, nine available removed grafts were examined for the presence of the CMV genome by DNA-hybridization in situ using a biotinylated CMV-DNA probe. Persistent CMV-DNA was found in all of those available grafts with chronic rejection. CMV-DNA was strongly expressed in the remaining bile ducts and moderately expressed in the endothelial cells of the vascular structures, the CMV positivity of hepatocytes varied from graft to graft. Thus, persistent CMV genome was found in those structures that are the major targets of the chronic rejection process in the liver. These findings support the previous suggestion of an association between CMV and chronic allograft rejection.

Fibrosis in chronic rejection of human liver allografts: expression patterns of transforming growth factor-TGFbeta1 and TGF-beta3

Activation and transformation of lipocytes (Ito cells, stellate cells) into alpha-actin-positive myofibroblast-like cells is an essential step in the initiation of liver fibrosis. Transforming growth factor-beta (TGF-beta) is considered an important mediator of this process. In order to determine mechanisms of fibrotic deposition in a hepatic transplant setting, we analyzed 10 chronically rejected human liver allografts for the expression of extracellular matrix (ECM) molecules, myofibroblast-like cells (alpha-actin), macrophages, and TGF-beta1 and -beta3. Using single- and double-immunohistochemical staining techniques, all specimens investigated showed increased deposition of the ECM proteins fibronectin, tenascin, undulin, and collagen VI with a characteristic densification especially in pericentral areas. Likewise, strong accumulation of alpha-actin-positive cells and TGF-beta1-expressing macrophages was observed in the same fields, supporting the concept of lipocyte activation/transformation and subsequent ECM production fostered by macrophage-derived TGF-beta1. In contrast, TGF-beta3 was found to be mainly expressed by a markedly increased number of lipocytes. Interestingly, distribution of TGF-beta3 corresponded to that of tenascin, an ECM molecule known to be involved in early matrix organization, suggesting that TGF-beta3 may likewise act mainly in early stages of fibrogenesis. Furthermore, TGF-beta3 restriction to high numbers of a single cell type (i.e., lipocytes) implied a possible role in cell proliferation through autocrine loops. In conclusion, fibrosis in chronic rejection seems to follow similar mechanisms as in non-transplanted livers but additionally suggests differential temporal and functional roles for the TGF-beta isoforms 1 and 3 in the course of a multistep process leading to lipocyte transformation and ECM production.

The impact of a positive crossmatch upon outcome after liver transplantation

Recent reports have shown that liver allografts transplanted against a positive lymphocytotoxic crossmatch (CDC+) are susceptible to an increased frequency of rejection, and decreases in patient and graft survival. The implication of a positive flow cytometric crossmatch (FCXM+) in liver transplantation remains controversial. The purpose of this study was to determine what impact a pretransplant IgG crossmatch due to CDC+ or FCXM+ had upon the clinical outcome following liver transplantation. Preoperative crossmatch status was determined prospectively in 110 consecutive liver transplants performed between July 1991 and January 1995. Allografts were divided into three groups: negative crossmatch (NXM), positive flow cytometric crossmatch FCXM+, and positive lymphocytotoxic crossmatch CDC+. Crossmatch status did not impact patient or graft survival. Actuarial patient survival was similar between groups at 12 months (88% vs. 95% vs. 92%, NXM vs. FCXM+ vs. CDC+) and 24 months (81% vs. 93% vs. 92%, NXM vs. FCXM+ vs. CDC+) (P=0.1938). Actuarial allograft survival was similar between groups at 12 months (76% vs. 93% vs. 85%, NXM vs. FCXM+ vs. CDC+) and 24 months (76% vs. 89% vs. 85%, NXM vs. FCXM+ vs. CDC+) (P=0.0738). CDC+ allografts had a significant increase in early rejection episodes compared with NXM (46% vs. 7%, CDC+ vs. NXM) (P=0.003) or FCXM+ allografts (46% vs. 10%, CDC+ vs. FCXM+) (P=0.006). CDC+ allografts experienced significantly more rejection episodes per year than NXM (53% vs. 20%, CDC+ vs. NXM) (P=0.015) or FCXM+ allografts (53% vs. 23%, CDC+ vs. FCXM+) (P=0.02). CDC+ allografts had a significant increase in numbers of additional nonconventional therapeutic interventions compared to NXM allografts (0.9+/-0.5 vs. 0.2+/-0.1, CDC+ vs. NXM) (P=0.039). The presence of cytotoxic antibodies pretransplantation is associated with increased incidences of early rejection, and rejection episodes per year. With careful monitoring and aggressive therapeutic interventions the presence of cytotoxic antibodies are not deleterious to patient or liver allograft survival.

Contributions of donor CD4 and CD8 cells to liver injury during murine graft-versus-host disease

We have determined the capacity of donor CD4 and CD8 T cells to mediate liver injury in the B10.D2 (donor) into BALB/c (host) chronic graft-versus-host disease (GVHD) model. First, we compared the effects of treating GVHD mice with anti-CD4 or anti-CD8 versus no treatment on the liver histology scores and elevated serum IgE levels in this model. We also examined the abilities of purified donor total T, CD4, and CD8 cells to mediate hepatic GVHD lesions. Anti-CD4 and anti-CD8 treatments caused profound depletion of peripheral CD4+ and CD8+ cells, respectively, and produced a relative enrichment of the CD8+ and CD4+ cells in the liver. Hepatic GVHD lesions and elevated serum IgE concentrations were both suppressed by anti-CD4 treatment. Anti-CD8 treatment had no effect on the severity of hepatic lesions and caused a significant increase in serum IgE levels. Attempts to induce hepatic GVHD with purified donor CD4 and CD8 cells were inconclusive because the onset of liver lesions was delayed and the lesions in both groups were contaminated by the opposite subset. Altogether, our results indicate that both hepatic lesions and elevated serum IgE concentrations in this GVHD model are dependent on donor CD4 cells. Donor CD4 cells mediated hepatic GVHD in the absence of CD8 cells. Donor CD8 cells did not produce hepatic GVHD in the absence of CD4 cells and appeared to be dependent on CD4 cells.

Duct-to-duct biliary reconstruction following liver transplantation for primary sclerosing cholangitis

The biliary complications in patients undergoing biliary reconstruction by duct-to-duct (D-D) anastomosis or with a Roux-en-Y loop (RL) at the time of liver transplantation for primary sclerosing cholangitis (PSC, 16 D-D, 10RL) or primary biliary cirrhosis (PBC, 31 D-D, 1 RL) were reviewed and compared. Patients were followed up for a mean period of 32 months. Extrahepatic biliary strictures occurred in 18.7%, 10% and 9.7% of DD-PSC, RL-PSC and DD-PBC patients, respectively, leaks in 6.2%, 20% and 6.4% DD-PSC, RL-PSC and DD-PBC patients, respectively (P = NS). Four intrahepatic biliary abnormalities developed in the PSC group. Duct-to-duct anastomosis did not significantly increase the risk of stricture formation or bile leaks in PSC patients compared to PBC patients. We conclude that duct-to-duct biliary reconstruction following liver transplantation for PSC is satisfactory unless the distal common bile duct is strictured.

Hepatitis C virus infection as a possible risk factor for ductopenic rejection (vanishing bile duct syndrome) after liver transplantation

Irreversible ductopenic rejection (DR) after orthotopic liver transplantation (OLT) is a major cause of late hepatic allograft failure. A variety of risk factors for DR have been postulated, but they are controversial. All transplant recipients at our institution with graft survival of more than 1 month (n = 120) were examined retrospectively with a view to possible risk factors for DR. These factors included age, sex, underlying liver disease, hepatitis B and C infections, donor-recipient CMV status, post-OLT CMV infections, immunosuppressive regimen, ABO blood type, and HLA class I and class II mismatches. Statistical analysis was performed with the univariate chi-square test or the two-tailed Fischer's exact test. Ten patients (8.3%) developed DR. Seventeen patients had HCV infections after OLT. In this group, the incidence of DR was highest (4 of 17, or 23.5%). This was significantly higher than for all other OLT groups (6 of 103 patients, or 5.8%; P < 0.03). The other factors analyzed did not reach statistical significance, including those that other authors found important for the development of DR. It may well be that hepatitis C infection predisposes one to the development of DR after OLT.

Early intragraft inflammatory events of liver allografts leading to chronic rejection

In this retrospective study, we have investigated the early intragraft inflammatory events of 12 liver allografts leading to chronic rejection. The cytological findings and clinical follow-up were analyzed in detail. Nine patients underwent at least one typical lymphoid activation of acute rejection, and three of them were treated more than once. Diagnosis of rejection was based on biopsy histology, cytology and liver dysfunction. In addition to the acute rejections, cytological analysis demonstrated in 11 of 12 grafts an unidentified lymphoid episode that differed from that of rejection. These lymphoid responses were associated with viral infections; cytomegalovirus (CMV) infection in 10 of 12 patients, hepatitis C virus (HCV) infection in 2 of 12 patients, 1 combined with CMV, and hepatitis B virus (HBV) infection in 1 patient. Graft dysfunction was still seen at the end of the follow-up. Thus, intragraft inflammation caused either by acute rejection or by viral infections may be involved in the induction of chronic rejection.

Hepatitis C virus infection as a possible risk factor for ductopenic rejection (vanishing bile duct syndrome) after liver transplantation

Irreversible ductopenic rejection (DR) after orthotopic liver transplantation (OLT) is a major cause of late hepatic allograft failure. A variety of risk factors for DR have been postulated, but they are controversial. All transplant recipients at our institution with graft survival of more than 1 month (n = 120) were examined retrospectively with a view to possible risk factors for DR. These factors included age, sex, underlying liver disease, hepatitis B and C infections, donor-recipient CMV status, post-OLT CMV infections, immunosuppressive regimen, ABO blood type, and HLA class I and class II mismatches. Statistical analysis was performed with the univariate chi-square test or the two-tailed Fischer's exact test. Ten patients (8.3%) developed DR. Seventeen patients had HCV infections after OLT. In this group, the incidence of DR was highest (4 of 17, or 23.5%). This was significantly higher than for all other OLT groups (6 of 103 patients, or 5.8%; P < 0.03). The other factors analyzed did not reach statistical significance, including those that other authors found important for the development of DR. It may well be that hepatitis C infection predisposes one to the development of DR after OLT.

Apoptosis and hepatobiliary disease

In this review we have attempted to summarize recent information on the role of apoptosis in normal liver biology and as a pathophysiological mechanism of cell death during hepatobiliary disease. Apoptosis is an important mechanism of cell injury and death in pathogenic settings as diverse as cell-mediated cytotoxicity, drug and chemical toxicity, carcinogenesis, viral disease, and autoimmune disease. Several factors account for the widespread attention and flurry of investigative activity into the phenomenon of apoptosis including the following: (1) realization that apoptosis is an important component of the behavior of all cells; (2) increasing evidence supporting a role for apoptotic cell death in diverse pathological settings; (3) elucidation of the biochemical pathways and insight into the genetic and molecular regulation of the process; and (4) development of new techniques to identify cells undergoing apoptosis. Recognition of the importance and role of apoptosis in hepatobiliary disease should stimulate interest and promote basic research toward understanding the mechanisms involved. Subsequent investigation into defining the cellular regulatory mechanisms and biochemical processes involved will be fertile ground for future research that may ultimately lead to novel therapeutic approaches for autoimmune diseases, malignancies, and viral disease.

Degeneration of intrahepatic bile duct with lymphocyte infiltration into biliary epithelial cells in biliary atresia

Degenerative changes of intrahepatic bile ducts with lymphocytic infiltration into portal areas have been recognized as the characteristic histopathologic features in the liver with biliary atresia (BA). Occasionally, lymphocytic infiltration into biliary ductal epithelium was noted and has been thought to be mostly the result of nonspecific chronic inflammation. However, this histological presentation looks quite similar to that of acute graft-versus-host disease (GVHD) after bone marrow transplantation (BMT) or acute cellular rejection (ACR) after orthotopic liver transplantation (OLTx). According to this histological similarity, we presumed that the degeneration of intrahepatic bile ducts (DIBD) might have developed with lymphocytic infiltration into biliary epithelial cells (LIBE) as some part of an immunologic reaction, and focused on the DIBD with LIBE in the patients with BA. Liver specimens obtained from 31 patients with BA at the time of primary Kasai operation and 3 patients at the time of reoperation were reviewed histologically, and investigated DIBD with LIBE. Nine patients with choledochal cyst (CBD) and 5 patients with neonatal hepatitis (NH) were added to this study as a control population. All patients with BA presented with DIBD with LIBE. On the other hand, only 2 patients with CBD presented with DIBD with LIBE, and no patients with NH presented with DIBD with LIBE. The DIBD with LIBE is not limited to patients with BA, but it seems to be much more serious in this group. These findings may suggest that some sort of immunologic factors contribute to the persistent DIBD in the patients with BA.(ABSTRACT TRUNCATED AT 250 WORDS)

Structural integrity and identification of causes of liver allograft dysfunction occurring more than 5 years after transplantation

The clinicopathologic features of liver allograft dysfunction occurring in 51 symptomatic recipients after more than 5 years' survival (mean 7.1 years) with the same hepatic allograft were compared with those of a similar group of 14 asymptomatic patients (mean survival, 9.9 years) who underwent a nonclinically indicated protocol liver biopsy evaluation. Predictably, patients who had clinically indicated biopsies more frequently showed histopathologic alterations (76% versus 36%, p < 0.002). After detailed clinicopathologic correlation, the changes in the symptomatic patients were attributed primarily to definite or presumed viral hepatitis in 17 of 51 (33%) patients, 11 of whom had recurrent viral disease; seven of 51 (14%) had nonviral recurrent original disease, three (6%) had obstructive cholangiopathy, and 11 (22%) had acute and/or chronic rejection. In 13 of 51 (25%) of the symptomatic patients, the clinical and pathologic abnormalities were minimal. Long-term liver allograft survival in nine of 14 (64%) of the asymptomatic patients was associated with minimally abnormal histologic alterations. Two of the asymptomatic patients had obstructive cholangiopathy; two others has recurrence of the original disease and one has possible viral hepatitis. Viral hepatitis types B and C, alcoholic liver disease, autoimmune hepatitis, granulomatous hepatitis (not otherwise specified), and probably primary biliary cirrhosis and primary sclerosing cholangitis were shown to recur after hepatic transplantation. The histopathologic changes associated with acute and chronic rejection frequently overlapped with other syndromes causing late dysfunction, such as chronic viral or autoimmune hepatitis, primary biliary cirrhosis, or primary sclerosing cholangitis; more than one insult could be identified in 15 cases, which made the differential diagnosis of causes of late liver allograft dysfunction much more difficult than early after hepatic transplantation. It is important to correlate the biopsy findings with the liver injury tests, the results of viral and autoimmune antibody serologic studies, and review of previous biopsies and to be aware of the original disease, recent changes in immunosuppression, and results of therapeutic intervention(s) to identify correctly the causes of liver allograft dysfunction in this patient population.

Apoptosis of bile duct epithelial cells in hepatic allograft rejection

Liver biopsy remains the 'gold standard' for monitoring rejection in liver transplant patients. Portal inflammation, bile duct damage and endothelialitis are recognized features of hepatic allograft rejection. The pathogenesis of the bile duct injury during rejection, however, remains unclear. To define the mechanism of bile duct damage, we studied the light- and electronmicroscopic appearance of hepatic tissue from selected patients in whom allograft failure was solely due to rejection. Of the 25 orthotopic liver transplant rejection cases examined, 17 were mild, seven were moderate and one was severe rejection. Light microscopy examination of the damaged bile duct epithelium revealed evidence of apoptosis which was confirmed by electronmicroscopy. Furthermore, there appeared to be a positive correlation between the grade of rejection and the number of apoptotic cells. Also included in the study were 13 cases of chronic active hepatitis and 10 normal livers which showed the least apoptotic cells. We conclude that the identification of apoptotic cells in damaged bile ducts in allograft biopsies might be helpful in the diagnosis of rejection and in assessment of the severity of rejection.