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Functional and morphological graft monitoring after liver transplantation
Clinica Chimica Acta 310 Ž2001. 17–23 www.elsevier.comrlocaterclinchim
Functional and morphological graft monitoring after liver transplantation Francesco Paolo Russo a , Marco Bassanello b, Marco Senzolo a , Umberto Cillo b, Patrizia Burra a,) a
Department of Surgical and Gastroenterological Sciences, Gastroenterology Section, UniÕersity of Padua, 35128 Padua, Italy b Department of Surgical and Gastroenterological Sciences, Surgical Section I, UniÕersity of Padua, 35128 Padua, Italy
Abstract The development of effective immunosuppressive drugs and the refinement of surgical procedures have led to remarkable improvements in the long-term success of liver transplantation. This procedure is now widely recognised as an effective, preferable therapeutic option for the treatment of end-stage liver disease. The early diagnosis of dysfunction is an indispensable tool for the successful management of the hepatic allograft recipient. Liver function is usually assessed by biochemical and morphological examinations, usually based on coagulation factors Žfibrinogen, fibrinogen degradation peptide, factor V, prothrombin time and prolonged thromboplastin time., transaminases, g-GT, ALP, bilirubin and lactic acid, and histology. Liver biopsy is usually performed before the implantation of the graft to assess the viability of the liver and following liver transplantation, whenever clinical events warrant it or as part of a routine biopsy schedule. q 2001 Elsevier Science B.V. All rights reserved. Keywords: Liver transplantation; Liver histological features; Liver function monitoring
1. Introduction The development of effective immunosuppressive drugs and the refinement of surgical procedures have led to remarkable improvements in the long-term success of liver transplantation. This procedure is now widely recognised as an effective, preferable therapeutic option for the treatment of end-stage liver disease.
) Corresponding author. Tel.: q39-49-821-2892; fax: q39-49876-0820. E-mail address: [email protected] ŽP. Burra..
However, there is still the risk of graft failure after transplantation due to several factors, e.g. prior transplantation, hospitalisation, intensive care or life support at the time of the transplant, renal insufficiency with creatinine ) 2 mgrdl before the operation and the donor’s age. Factors associated with the risk of graft failure or the patient’s death are the recipient’s gender, racerethnic origin, metabolic disease and the grafting of a living donor liver. The 1and 5-year graft survival rates among adult recipients are 75–80% and 50–65%, respectively w1x. Liver function is usually assessed by biochemical and morphological examinations. The early diagnosis of dysfunction is an indispensable tool for the successful management of the hepatic allograft recipient.
0009-8981r01r$ - see front matter q 2001 Elsevier Science B.V. All rights reserved. PII: S 0 0 0 9 - 8 9 8 1 Ž 0 1 . 0 0 5 0 6 - X
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F.P. Russo et al.r Clinica Chimica Acta 310 (2001) 17–23
2. Functional monitoring Diagnosis and management of graft dysfunction following transplantation are usually based on biochemical tests, such as coagulation factors Žfibrinogen, fibrinogen degradation peptide, factor V, prothrombin time and prolonged thromboplastin time., transaminases, g-GT, ALP, bilirubin and lactic acid. Postoperative graft failure or primary non-function affects 7–10% of grafts and usually requires emergency retransplantation w2–6x. Poor graft function soon after liver transplantation is an important cause of morbidity and mortality. Deschenes et al. w7x defined early allograft dysfunction ŽEAD. by using readily available function indices and identified donor, graft, and pretransplantation recipient factors associated with this outcome. EAD was defined by the presence of at least one of the following factors between 2 and 7 days after transplantation: serum bilirubin ) 10 mgrdl, prothrombin time ŽPT. G 17 s, and hepatic encephalopathy. They reported EAD incidence in 23% of cases. Median intensive care unit ŽICU. and hospital stays were longer for recipients with than for those without EAD Ž4 days vs. 3 days, P s 0.0001; 24 vs. 15 days, P s 0.0001, respectively.. Three-year recipient and graft survivals were worse in those who had had EAD than in those who had not Ž68% vs. 83%, P s 0.0001; 61% vs. 79%, P s 0.0001.. A logistic regression model combining donor, graft, and recipient factors predicted EAD better than models examining these factors in isolation. Pretransplant recipient elevations in PT and bilirubin while awaiting a graft in hospital or in the ICU, donor age G 50 years, donor hospital stay ) 3 days, preprocurement acidosis, and cold ischemia time G 15 h were independently associated with EAD. The liver has a fundamental role in the clearance of many xenobiotic compounds. Dynamic tests consist in the clearance of administered compounds such as indocyanin green, bromosulphthalein, antipyrine, galactose, and caffeine. These tests usually require multiple blood samples over several hours, thus, limiting their routine clinical use. More advances in this field have been reached with the rate of formation and appearance of metabolites, e.g. 14 C-labeled CO from w14 Cx erythromycin or aminopyrine; in the latter group, the most used in clinical practice is the
lidocaine–monoethyl glycinexlidide test. Recently, the intraoperative quantification of hepatic microperfusion as a predictor of initial graft function has been developed. A Spanish group evaluated the importance of the cytoplasmatic redox state Ždetermined by the lactaterpyruvate ratio wLPRx. in the interpretation of hepatic metabolism in patients who have undergone an orthotopic liver transplantation w8x. After reperfusion of the graft, there is a significant increase in energy demand, by means of a hormone signal, via the two main energy pathways, i.e. glycolysis and oxidation of fatty acids w9x. The end products of glycolysis are lactate and NADH, but a surplus of the latter leads to inhibition of citrate synthetase and pyruvate dehydrogenase, blocking the Krebs cycle. The reduced status in the cytoplasm is reflected by high levels of lactate and LPR. The authors found that patients who need ) 4 days of ICU stay or ) 14 days of total hospital stay after transplantation show an increase in parameters that reflect a reduced state in the cytoplasm. These glycolytic parameters have also correlated well with evolution in patients who have undergone liver transplantation. As LPR is regulated by pyruvate levels, postoperative complications might be due, to a large extent, to systemic complications Žhigh levels of lactate with normal LPR.. In recent years, most researchers have concentrated on studying immunological graft monitoring. This kind of research investigates the role of cytokines, produced by both the recipient and the newly vascularised allograft, such as central mediators in the inflammatory response to allografted tissue. Boros et al. w10x examined the relationship between pre- and intra-operative levels of TNF, IL-1, IL-6, and IL-8 and hepatic allograft function in the early postoperative period and also determined which cytokines are produced in a significant amount by the newly vascularised allograft. Baseline levels of IL-6 and IL-8 tended to be higher in patients with more advanced disease and showed an increase during the anhepatic period. TNF and IL-1 remained stable from the baseline to the anhepatic phase. IL-1 showed an increase from portal vein to effluent samples, suggesting that the graft gives an important contribution to circulating IL-1 levels. Analysis of the data in the light of early graft performance revealed extremely high levels of IL-1, IL-6 and IL-8
F.P. Russo et al.r Clinica Chimica Acta 310 (2001) 17–23
effluent, and a prolonged elevation of the latter two cytokines in patients with poor early graft function. These findings demonstrate that sequential perioperative measurements of proinflammatory cytokines can be useful in monitoring graft function.
3. Morphological monitoring Liver biopsy is usually performed before the implantation of the graft to assess the viability of the liver. Following liver transplantation, biopsy can be performed whenever clinical events warrant it, e.g. a rise in transaminases, or as part of a routine biopsy schedule. At our Liver Transplant Unit, we routinely perform liver biopsy at 6 and 12 months and then yearly after liver transplantation or to confirm a clinical andror biochemical suspicion of acute or chronic rejection or recurrence of previous liver disease. Justification for doing protocol biopsies, rather than doing a biopsy when liver tests suggest graft dysfunction without identifying the cause, lies on the premise that w11x: Ø function tests are associated with poor sensitivity and specificity in the diagnosis of graft dysfunction; Ø liver function tests provide little information on the severity of graft damage; Ø graft function is better preserved if liver damage is diagnosed and treated early; Ø knowledge of the histological changes in the allograft in different clinical situations results in better management of the overall patient population. Liver dysfunction may depend on hepatocellular or biliary or endothelial damage. The histological changes of large-duct biliary obstruction include different features. Ž1. Portal edema, proliferation of ducts and ductules, zone 3 cholestasis Žbiliary obstruction.. Biliary complications are a common cause of morbidity following orthotopic liver transplantation. Complications involving the biliary tree occur in 6–34% of transplantations, usually within the first 3 months after transplantation. Bile leaks and biliary strictures are the most common biliary complications, but Oddi
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sphincter dysfunction, haemobilia, and biliary obstruction by stones, sludge, or casts have also been described. The risk of specific biliary complications is related to the type of biliary reconstruction performed at the time of transplantation w12x. Ž2. Non-zonal coagulation necrosis of hepatic tissue or zonal necrosis, involving zone 3 of the lobules Žischemic lesions.. The use of liver allografts with warm or cold ischemia, functional and morphological alterations in hepatocytes, sinusoidal endothelial cells and Kupffer cells was evaluated in a rat transplantation model w13x. All recipients of allografts with either 4 h of cold or 30 min of warm ischemia lived more than 22 days and were judged viable. On one hand, all recipients of grafts with 6 h of cold or 60 min of warm ischemia died within 2 days and were therefore judged to be non-viable. With these viable and non-viable allograft models, hepatocyte function was evaluated by the bile output and serum glutamic–oxaloacetic transaminase, serum glutamic–pyruvic transaminase, and serum lactate dehydrogenase levels; endothelial cell function was judged by the serum hyaluronic acid level, and Kupffer cell function was measured by an intravenous colloidal carbon clearance test. Hepatocyte injury was the prominent feature in warm ischemic grafts, especially in the non-viable ones. On the other hand, serum hyaluronic acid values were significantly higher in the non-viable cold ischemic group, compared with the viable counterpart, suggesting that the functional depression of endothelial cells was predominant in cold, non-viable livers. Histological findings coincided with the above results. The inflammatory activity of Kupffer cells was depressed by warm or cold ischemia, whereas the number of Kupffer cells was reduced in the warm ischemia group. The authors concluded that in liver allografts the main site of injury in warm ischemia is the hepatocyte and suggested that cold ischemia is associated with endothelial cell damage. Batts w14x demonstrated that in an animal model of ischemiareperfusion injury, hepatic sinusoidal congestion, liver necrosis, and apoptosis 30 min after reperfusion were significantly less evident in the group of pigs treated with L-arginine compared to controls. Ž3. Portal tract inflammation, bile duct damage, portal andror central endothelitis; cholestasis; parenchymal changes Žacute cellular rejection.; loss
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of small bile ducts within the portal tracts Žchronic rejection.. Hepatic allograft rejection has been divided into humoral Žor hyperacute., acute Žor cellular., and chronic Žor ductopenic. forms. Humoral rejection is extremely uncommon in the liver and is not graded. Acute rejection will occur in approximately 50% of liver allografts, is more common in the first few weeks after transplantation, and is defined by Snover’s triad of portal hepatitis, endothelialitis Žor endothelitis., and lymphocytic cholangitis. This form of rejection is generally reversible, either spontaneously or with additional immunosuppressive therapy, and can be reliably graded using a system with categories of mild, moderate, and severe rejection, associated with 37%, 48%, and 75% of unfavourable short-term and 1%, 12%, and 14% of unfavourable long-term outcomes, respectively. Chronic rejection is characterised histologically by progressive duct loss and a lipid-rich vasculopathy that can be difficult to diagnose in the early phases. Chronic rejection typically occurs several months to 1 year after transplantation, though exceptions exist w15x. Ž4. Presence of parenchymal micro-abscesses ŽMA. in liver transplant biopsies is frequently associated with cytomegalovirus ŽCMV. infection. However, other potential causes of MA have not been fully investigated. Lamps et al. w16x studied additional etiologies for MA via histological evaluation and clinicopathological correlation. Three hundred seventy-two liver transplant biopsies from 97 patients Žfrom 1991 to 1997. were reviewed and stained immunohistochemically for CMV. Numerous histological features were evaluated, including size and number of MA, lobular and portal inflammation, and cholestasis. Medical records were reviewed for radiographic, laboratory, and other clinical data from the time of biopsy. Sixty-two of 372 biopsies Ž17%. from 43 patients contained MA. Biopsies were obtained between 4 days and 2.3 years after the transplant Žmedian 14 days.. Nineteen percent of biopsies had CMV infection at the time of biopsy; 27% were associated with other bacterial, viral, or fungal infections; 10% had graft ischemia; 15% had biliary obstructionrcholangitis; 3% had a combination of ischemia and sepsis; and no explanation was found in 26% of biopsies. Numerous MA within a biopsy Ž) 9. correlated with CMV infection Ž P - 0.005.;
no other histological features, including size of MA, correlated with the etiology of MA. Overall, 43 of 97 Ž44%. liver transplantation patients had biopsies demonstrating MA at some point in their post-transplantation course. CMV infection appears to be responsible for only a minority of cases. MA, though non-specific, are an important histological finding in numerous conditions that may have a significant impact on both graft survival and overall patient morbidity. Ž5. Recurrence of primary liver disease. The diagnosis of recurrent disease in the allograft has been a matter of controversy. The diseases at risk of recurrence are: primary biliary cirrhosis ŽPBC., autoimmune hepatitis ŽAIH., primary sclerosing cholangitis ŽPSC., HCV- and HBV-related disease. Recurrence of primary biliary cirrhosis ŽPBC. in liver allografts remains a controversial issue. Sebagh et al. w17x evaluated this risk and tried to determine the presence, if any, of a predictive histological feature. They reviewed the most recent and the 1-year protocol liver biopsies of 69 patients who received transplants for PBC vs. 53 control patients. Histological features consistent with PBC recurrence included non-suppurating destructive cholangitis, mixed portal infiltrate, fibrosis, and ductopenia. A complete evaluation was undertaken in each patient with these histological features, which occurred in six patients who received transplants for PBC Ž8.7% vs. 0% in the control group. from 1 to 8 years after transplantation. In five of the six patients, anti-mitochondrial-2 Žanti-M2. antibodies remained at high titers. Cholestasis was present in four patients, and clinical symptoms in two. All six patients were negative for HCV and HCV-RNA in their serum. None had bile duct obstruction. The presence of plasma cells in the portal infiltrate at 1 year after the transplant was predictive of this risk of recurrence. The risk of PBC recurrence is real Ž8.7%.. AIH may recur after liver transplantation and it is difficult to diagnose. Ayata et al. w18x defined the histopathology and factors related to AIH recurrence. Fourteen of 475 patients received LT for AIH; two died perioperatively. Liver specimens Žnative and post-transplant biopsies. from 12 other patients were reviewed and correlated with pre- and post-transplant clinical course and outcome. Recurrent AIH was seen in 5 of 12 patients, 35 to 280 days post-trans-
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plant as lobular hepatitis with acidophil bodies and lymphoplasmacytic infiltrate. Portalrinterface hepatitis was seen with disease progression and two of five patients developed cirrhosis. Of seven non-recurrent patients, one had acquired hepatitis C with lobularrportal hepatitis and none developed cirrhosis. Histology suggestive of overlap syndrome was seen in 3 of 12 native livers with no effect on post-transplant course or pathology. High-grade necro-inflammation was present in native livers at transplant in five of five cases with recurrent AIH and in one of seven without recurrence Ž P - 0.01.. Pre-transplant disease duration, donorrrecipient gender distribution, HLA studies, and rejection episodes did not correlate with AIH recurrence. The authors conclude that Ž1. recurrent AIH is not uncommon and was seen in 42% of patients with lymphoplasmacytic lobular, portal, and interface hepatitis; Ž2. acidophil bodies with lymphoplasmacytic cells are seen in early recurrent AIH; Ž3. recurrent AIH appears at variable times post-LT, and its progression is slow; Ž4. high-grade inflammation in native liver at LT is a strong predictor of recurrent AIH. Fibro-obliterative lesions and fibrous cholangitis are characteristic histological lesions of primary sclerosing cholangitis. To determine whether such lesions can be found in the liver allograft, and whether they represent recurrent disease, Harrison et al. w19x reviewed all consecutive histological material taken more than 6 months after transplantation in a 3-year period from a series of 207 liver transplantations Ž22 with primary sclerosing cholangitis, 185 controls without primary sclerosing cholangitis.. Because patients with primary sclerosing cholangitis have a biliary system reconstructed by means of a Roux loop, they compared the findings with those from a further control group of patients who had received a Roux loop for reasons other than primary sclerosing cholangitis. Of 22 patients receiving liver transplants for primary sclerosing cholangitis, 7 Ž32%. patients had biopsy specimens showing features of biliary obstruction, 6 Ž27%. showed fibrous cholangitis, and 3 Ž14%. showed classic fibro-obliterative lesions. These findings compared with 3 Ž14%., 1 Ž5%. and 0 of the 22 Roux controls, and 19 Ž10%., 4 Ž2%. and 0 of the 185 controls without primary sclerosing cholangitis, respectively. The three patients with fibro-obliterative lesions either had clinical episodes
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of cholangitis or had micro-organisms in the large bile ducts. However, both biliary obstructive features and fibrous cholangitis were more common in primary sclerosing cholangitis, and fibro-obliterative lesions were only found in patients who received transplants for primary sclerosing cholangitis, despite the presence of cholangitis and Roux loops in control patients. The time progression of allograft damage in patients with recurrent hepatitis C after orthotopic liver transplantation has not been precisely determined. Testa et al. w20x analysed the progression of disease recurrence and its impact on patient and graft survival. Data on 300 patients who underwent transplantation for hepatitis C were analyzed regarding the incidence of histological recurrence, risk factors, immunosuppressive regimen, rejection episodes, and survival. For patients with histological recurrence, the timing and risks for disease progression were analyzed. Data on 30 patients who underwent retransplantation were studied. Histological recurrence occurred in 40.3% of patients, 27.2% of whom progressed to bridging fibrosis or cirrhosis. Eighty-seven percent of the patients experienced recurrence of disease within 24 months of transplantation. Patients with histological recurrence within 6 months of liver transplantation had a greater risk for progression to cirrhosis than patients recurring later on Žrisk ratio, 2.3.. Recurrence within 1 year was associated with decreased patient and graft survival rates at 1 and 5 years Ž65.1% and 56.4% vs. 80.6% and 78.4%; P s 0.004 and P s 0.0008, respectively.. Patients with histological recurrence had a greater incidence of acute cellular rejection, as well as multiple episodes of rejection, steroid-resistant rejections, and greater cumulative doses of corticosteroids. Demetris et al. w21x evaluated the morphologic evolution of hepatitis B virus ŽHBV. liver disease in 45 hepatic allograft recipients who were HBV surface-antigen positive ŽHBs-Agq . at the time of liver replacement and who survived for more than 60 days. They were studied by routine histological and immunocytochemical analysis of serial pathology specimens. The findings in these patients were compared to a control group of 30 individuals who were immune to the HBV Žanti-HBs antibody positive., but required hepatic replacement for other reasons. Eight of the 45 Ž18%. HBsAg-positive patients had
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no serologic evidence of HBV re-infection after transplantation. All 37 remaining patients were re-infected; 21 Ž47%. developed chronic active hepatitis andror cirrhosis, 3 Ž7%. developed submassive necrosis, and 6 Ž14%. developed chronic lobular hepatitis. One patient lost her graft to chronic rejection, despite re-infection with the B virus. Four other patients Ž9%. developed a chronic carrier status. No long-term follow-up biopsies were available in the remaining two patients. The histological features associated with dysfunction related to recurrent HBV infection evolved from an acute to chronic phase and were similar to hepatitis B seen in non-allografted livers. Furthermore, HBV-related lesions could be separated from rejection using routine histology alone. The only exception to this conclusion was the occurrence of a peculiar HBV-related lesion in two recipients. Immunohistochemical analysis demonstrated the presence of viral antigens in almost all cases. Hepatic inflammation was also commonly present in HBV disease and consisted mostly of accessory cells and T lymphocytes. Analysis of the effect of major histocompatibility complex matching revealed no clear association between the number of class I or II matches or mismatches and the development, or pattern, of active hepatitis in the allograft. Peculiar pathological alterations in several of the biopsies and failed allografts after HBV re-infection suggest that, under certain circumstances, the B virus may be cytopathic.
4. Conclusion Morphological monitoring of graft function following liver transplantation relies mainly on histopathological evaluation since liver biopsy is the gold standard to make the diagnosis of hepatic damage. Biochemical andror instrumental examinations should be performed to complete the clinical assessment in the early- and long-term liver function follow-up.
References w1x Smith CM, Davies DB, McBride, MA. Liver transplantation in the United States: a report from the UNOS Liver Transplant Registry Clinical Transplantation 1999;23–34.
w2x Mokowka L, Gordon RD, Todo S, et al. Analysis of donor criteria for the prediction of outcome in clinical liver transplantation. Transplant Proc 1987;19:2378–82. w3x Howard TK, Klintman GB, Cofer JB, Husberg BS, Goldstein RM, Gonwa TA. The influence of preservation injury on rejection in the hepatic transplant recipient. Transplantation 1990;49:103–7. w4x Ploeg RJ, D’Alessandro AM, Knechtle SJ, et al. Risk factors for primary dysfuncion after liver transplantation: a multivariate analysis. Transplantation 1993;55:807–13. w5x Gonzalez FX, Rimola A, Grande L, et al. Predictive factors of early postoperative graft function in human liver transplantation. Hepatology 1994;20:565–73. w6x Strasberg SM, Howard TK, Molmenti EP, Hertl M. Selecting the donor liver: risk factors for poor function after orthotopic liver transplantation. Hepatology 1994;20:829–38. w7x Deschenes M, Belle SH, Krom RAF, Zetterman RK, Lake JR. Early allograft dysfunction after liver transplantation. Transplantation 1998;66Ž3.:302–10. w8x Igea J, Nuno J, Lopez-Hervas P, et al. Evaluation of glycolytic parameters and cytoplasmatic redox status as markers of hepatic function in liver transplantation. Transplant Proc 1999;31:2443–4. w9x Nakatani T, Ozawa K, Asano M, Ukikusa M, Kamiyama Y, Tobe T. Changes in predominant energy substrate after hepatectomy. Life Sci 1981;28Ž3.:257–64. w10x Boros P, Suehiro T, Curtiss S, et al. Differential contribution of graft and recipient to perioperative TNF-alpha, IL-1 beta, IL-6 and IL-8 levels and correlation with early graft function in clinical liver transplantation. Clin Transplant 1997;11: 588–92. w11x Neuberger J, Wilson P, Adams D. Protocol liver biopsies: the case in favour. Transplant Proc 1998;30:1497–9. w12x Tung BY, Kimmey MB. Biliary complications of orthotopic liver transplantation. Dig Dis Sci 1999;17Ž3.:133–44. w13x Ikeda T, Yanaga K, Kishikawa K, Kazikoe S, Shimada M, Sugimachi K. Ischemic injury in liver transplantation: difference in injury site between warm and cold ischemia in rats. Hepatology 1992;16Ž2.:454–61. Aug. w14x Batts KP. Acute and chronic hepatic allograft rejection: pathology and classification. Liver Transplant Surg 1999; 5Ž4.:S21–9. Suppl. 1. w15x Burra P, Chirizzi L, Cadrobbi R, et al. Evaluation of liver function and morphology following ischemia-reperfusion injury in pigs. Transplant Proc 1997;29:3515–7. w16x Lamps LW, Pinson CW, Rainford DS, Shyr Y, Scott MA, Washington MK. The significance of microabscesses in liver transplant biopsies: a clinicopathological study. Hepatology 1998;28Ž6.:1532–7. Dec. w17x Sebagh M, Farges O, Dubel L, Samuel D, Bismuth H, Reynes M. Histological features predictive of recurrence of primary biliary cirrhosis after liver transplantation. Transplantation 1998;65Ž10.:1328–33. w18x Ayata G, Gordon FD, Lewis WD, et al. Liver transplantation for autoimmune hepatitis: a long-term pathologic study. Hepatology 2000;32Ž2.:185–92. w19x Harrison RF, Davies MH, Neuberger JM, Hubscher S. Fibrous and obliterative cholangitis in liver allograft: evidence
F.P. Russo et al.r Clinica Chimica Acta 310 (2001) 17–23 of recurrent primary sclerosing cholangitis? Hepatology 1994;20Ž2.:356–61. w20x Testa G, Crippin JS, Netto GJ, et al. Liver transplantation for hepatitis C: recurrence and disease progression in 300 patients. Liver Transplant 2000;6Ž5.:553–61.
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w21x Demetris AJ, Todo S, Van Thiel DH, et al. Evaluation of hepatitis B virus liver disease after hepatic replacement. Practical and theoretical considerations. Am J Pathol 1990;137Ž3.:667–76.
Functional and morphological graft monitoring after liver transplantation Francesco Paolo Russo a , Marco Bassanello b, Marco Senzolo a , Umberto Cillo b, Patrizia Burra a,) a
Department of Surgical and Gastroenterological Sciences, Gastroenterology Section, UniÕersity of Padua, 35128 Padua, Italy b Department of Surgical and Gastroenterological Sciences, Surgical Section I, UniÕersity of Padua, 35128 Padua, Italy
Abstract The development of effective immunosuppressive drugs and the refinement of surgical procedures have led to remarkable improvements in the long-term success of liver transplantation. This procedure is now widely recognised as an effective, preferable therapeutic option for the treatment of end-stage liver disease. The early diagnosis of dysfunction is an indispensable tool for the successful management of the hepatic allograft recipient. Liver function is usually assessed by biochemical and morphological examinations, usually based on coagulation factors Žfibrinogen, fibrinogen degradation peptide, factor V, prothrombin time and prolonged thromboplastin time., transaminases, g-GT, ALP, bilirubin and lactic acid, and histology. Liver biopsy is usually performed before the implantation of the graft to assess the viability of the liver and following liver transplantation, whenever clinical events warrant it or as part of a routine biopsy schedule. q 2001 Elsevier Science B.V. All rights reserved. Keywords: Liver transplantation; Liver histological features; Liver function monitoring
1. Introduction The development of effective immunosuppressive drugs and the refinement of surgical procedures have led to remarkable improvements in the long-term success of liver transplantation. This procedure is now widely recognised as an effective, preferable therapeutic option for the treatment of end-stage liver disease.
) Corresponding author. Tel.: q39-49-821-2892; fax: q39-49876-0820. E-mail address: [email protected] ŽP. Burra..
However, there is still the risk of graft failure after transplantation due to several factors, e.g. prior transplantation, hospitalisation, intensive care or life support at the time of the transplant, renal insufficiency with creatinine ) 2 mgrdl before the operation and the donor’s age. Factors associated with the risk of graft failure or the patient’s death are the recipient’s gender, racerethnic origin, metabolic disease and the grafting of a living donor liver. The 1and 5-year graft survival rates among adult recipients are 75–80% and 50–65%, respectively w1x. Liver function is usually assessed by biochemical and morphological examinations. The early diagnosis of dysfunction is an indispensable tool for the successful management of the hepatic allograft recipient.
0009-8981r01r$ - see front matter q 2001 Elsevier Science B.V. All rights reserved. PII: S 0 0 0 9 - 8 9 8 1 Ž 0 1 . 0 0 5 0 6 - X
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2. Functional monitoring Diagnosis and management of graft dysfunction following transplantation are usually based on biochemical tests, such as coagulation factors Žfibrinogen, fibrinogen degradation peptide, factor V, prothrombin time and prolonged thromboplastin time., transaminases, g-GT, ALP, bilirubin and lactic acid. Postoperative graft failure or primary non-function affects 7–10% of grafts and usually requires emergency retransplantation w2–6x. Poor graft function soon after liver transplantation is an important cause of morbidity and mortality. Deschenes et al. w7x defined early allograft dysfunction ŽEAD. by using readily available function indices and identified donor, graft, and pretransplantation recipient factors associated with this outcome. EAD was defined by the presence of at least one of the following factors between 2 and 7 days after transplantation: serum bilirubin ) 10 mgrdl, prothrombin time ŽPT. G 17 s, and hepatic encephalopathy. They reported EAD incidence in 23% of cases. Median intensive care unit ŽICU. and hospital stays were longer for recipients with than for those without EAD Ž4 days vs. 3 days, P s 0.0001; 24 vs. 15 days, P s 0.0001, respectively.. Three-year recipient and graft survivals were worse in those who had had EAD than in those who had not Ž68% vs. 83%, P s 0.0001; 61% vs. 79%, P s 0.0001.. A logistic regression model combining donor, graft, and recipient factors predicted EAD better than models examining these factors in isolation. Pretransplant recipient elevations in PT and bilirubin while awaiting a graft in hospital or in the ICU, donor age G 50 years, donor hospital stay ) 3 days, preprocurement acidosis, and cold ischemia time G 15 h were independently associated with EAD. The liver has a fundamental role in the clearance of many xenobiotic compounds. Dynamic tests consist in the clearance of administered compounds such as indocyanin green, bromosulphthalein, antipyrine, galactose, and caffeine. These tests usually require multiple blood samples over several hours, thus, limiting their routine clinical use. More advances in this field have been reached with the rate of formation and appearance of metabolites, e.g. 14 C-labeled CO from w14 Cx erythromycin or aminopyrine; in the latter group, the most used in clinical practice is the
lidocaine–monoethyl glycinexlidide test. Recently, the intraoperative quantification of hepatic microperfusion as a predictor of initial graft function has been developed. A Spanish group evaluated the importance of the cytoplasmatic redox state Ždetermined by the lactaterpyruvate ratio wLPRx. in the interpretation of hepatic metabolism in patients who have undergone an orthotopic liver transplantation w8x. After reperfusion of the graft, there is a significant increase in energy demand, by means of a hormone signal, via the two main energy pathways, i.e. glycolysis and oxidation of fatty acids w9x. The end products of glycolysis are lactate and NADH, but a surplus of the latter leads to inhibition of citrate synthetase and pyruvate dehydrogenase, blocking the Krebs cycle. The reduced status in the cytoplasm is reflected by high levels of lactate and LPR. The authors found that patients who need ) 4 days of ICU stay or ) 14 days of total hospital stay after transplantation show an increase in parameters that reflect a reduced state in the cytoplasm. These glycolytic parameters have also correlated well with evolution in patients who have undergone liver transplantation. As LPR is regulated by pyruvate levels, postoperative complications might be due, to a large extent, to systemic complications Žhigh levels of lactate with normal LPR.. In recent years, most researchers have concentrated on studying immunological graft monitoring. This kind of research investigates the role of cytokines, produced by both the recipient and the newly vascularised allograft, such as central mediators in the inflammatory response to allografted tissue. Boros et al. w10x examined the relationship between pre- and intra-operative levels of TNF, IL-1, IL-6, and IL-8 and hepatic allograft function in the early postoperative period and also determined which cytokines are produced in a significant amount by the newly vascularised allograft. Baseline levels of IL-6 and IL-8 tended to be higher in patients with more advanced disease and showed an increase during the anhepatic period. TNF and IL-1 remained stable from the baseline to the anhepatic phase. IL-1 showed an increase from portal vein to effluent samples, suggesting that the graft gives an important contribution to circulating IL-1 levels. Analysis of the data in the light of early graft performance revealed extremely high levels of IL-1, IL-6 and IL-8
F.P. Russo et al.r Clinica Chimica Acta 310 (2001) 17–23
effluent, and a prolonged elevation of the latter two cytokines in patients with poor early graft function. These findings demonstrate that sequential perioperative measurements of proinflammatory cytokines can be useful in monitoring graft function.
3. Morphological monitoring Liver biopsy is usually performed before the implantation of the graft to assess the viability of the liver. Following liver transplantation, biopsy can be performed whenever clinical events warrant it, e.g. a rise in transaminases, or as part of a routine biopsy schedule. At our Liver Transplant Unit, we routinely perform liver biopsy at 6 and 12 months and then yearly after liver transplantation or to confirm a clinical andror biochemical suspicion of acute or chronic rejection or recurrence of previous liver disease. Justification for doing protocol biopsies, rather than doing a biopsy when liver tests suggest graft dysfunction without identifying the cause, lies on the premise that w11x: Ø function tests are associated with poor sensitivity and specificity in the diagnosis of graft dysfunction; Ø liver function tests provide little information on the severity of graft damage; Ø graft function is better preserved if liver damage is diagnosed and treated early; Ø knowledge of the histological changes in the allograft in different clinical situations results in better management of the overall patient population. Liver dysfunction may depend on hepatocellular or biliary or endothelial damage. The histological changes of large-duct biliary obstruction include different features. Ž1. Portal edema, proliferation of ducts and ductules, zone 3 cholestasis Žbiliary obstruction.. Biliary complications are a common cause of morbidity following orthotopic liver transplantation. Complications involving the biliary tree occur in 6–34% of transplantations, usually within the first 3 months after transplantation. Bile leaks and biliary strictures are the most common biliary complications, but Oddi
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sphincter dysfunction, haemobilia, and biliary obstruction by stones, sludge, or casts have also been described. The risk of specific biliary complications is related to the type of biliary reconstruction performed at the time of transplantation w12x. Ž2. Non-zonal coagulation necrosis of hepatic tissue or zonal necrosis, involving zone 3 of the lobules Žischemic lesions.. The use of liver allografts with warm or cold ischemia, functional and morphological alterations in hepatocytes, sinusoidal endothelial cells and Kupffer cells was evaluated in a rat transplantation model w13x. All recipients of allografts with either 4 h of cold or 30 min of warm ischemia lived more than 22 days and were judged viable. On one hand, all recipients of grafts with 6 h of cold or 60 min of warm ischemia died within 2 days and were therefore judged to be non-viable. With these viable and non-viable allograft models, hepatocyte function was evaluated by the bile output and serum glutamic–oxaloacetic transaminase, serum glutamic–pyruvic transaminase, and serum lactate dehydrogenase levels; endothelial cell function was judged by the serum hyaluronic acid level, and Kupffer cell function was measured by an intravenous colloidal carbon clearance test. Hepatocyte injury was the prominent feature in warm ischemic grafts, especially in the non-viable ones. On the other hand, serum hyaluronic acid values were significantly higher in the non-viable cold ischemic group, compared with the viable counterpart, suggesting that the functional depression of endothelial cells was predominant in cold, non-viable livers. Histological findings coincided with the above results. The inflammatory activity of Kupffer cells was depressed by warm or cold ischemia, whereas the number of Kupffer cells was reduced in the warm ischemia group. The authors concluded that in liver allografts the main site of injury in warm ischemia is the hepatocyte and suggested that cold ischemia is associated with endothelial cell damage. Batts w14x demonstrated that in an animal model of ischemiareperfusion injury, hepatic sinusoidal congestion, liver necrosis, and apoptosis 30 min after reperfusion were significantly less evident in the group of pigs treated with L-arginine compared to controls. Ž3. Portal tract inflammation, bile duct damage, portal andror central endothelitis; cholestasis; parenchymal changes Žacute cellular rejection.; loss
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of small bile ducts within the portal tracts Žchronic rejection.. Hepatic allograft rejection has been divided into humoral Žor hyperacute., acute Žor cellular., and chronic Žor ductopenic. forms. Humoral rejection is extremely uncommon in the liver and is not graded. Acute rejection will occur in approximately 50% of liver allografts, is more common in the first few weeks after transplantation, and is defined by Snover’s triad of portal hepatitis, endothelialitis Žor endothelitis., and lymphocytic cholangitis. This form of rejection is generally reversible, either spontaneously or with additional immunosuppressive therapy, and can be reliably graded using a system with categories of mild, moderate, and severe rejection, associated with 37%, 48%, and 75% of unfavourable short-term and 1%, 12%, and 14% of unfavourable long-term outcomes, respectively. Chronic rejection is characterised histologically by progressive duct loss and a lipid-rich vasculopathy that can be difficult to diagnose in the early phases. Chronic rejection typically occurs several months to 1 year after transplantation, though exceptions exist w15x. Ž4. Presence of parenchymal micro-abscesses ŽMA. in liver transplant biopsies is frequently associated with cytomegalovirus ŽCMV. infection. However, other potential causes of MA have not been fully investigated. Lamps et al. w16x studied additional etiologies for MA via histological evaluation and clinicopathological correlation. Three hundred seventy-two liver transplant biopsies from 97 patients Žfrom 1991 to 1997. were reviewed and stained immunohistochemically for CMV. Numerous histological features were evaluated, including size and number of MA, lobular and portal inflammation, and cholestasis. Medical records were reviewed for radiographic, laboratory, and other clinical data from the time of biopsy. Sixty-two of 372 biopsies Ž17%. from 43 patients contained MA. Biopsies were obtained between 4 days and 2.3 years after the transplant Žmedian 14 days.. Nineteen percent of biopsies had CMV infection at the time of biopsy; 27% were associated with other bacterial, viral, or fungal infections; 10% had graft ischemia; 15% had biliary obstructionrcholangitis; 3% had a combination of ischemia and sepsis; and no explanation was found in 26% of biopsies. Numerous MA within a biopsy Ž) 9. correlated with CMV infection Ž P - 0.005.;
no other histological features, including size of MA, correlated with the etiology of MA. Overall, 43 of 97 Ž44%. liver transplantation patients had biopsies demonstrating MA at some point in their post-transplantation course. CMV infection appears to be responsible for only a minority of cases. MA, though non-specific, are an important histological finding in numerous conditions that may have a significant impact on both graft survival and overall patient morbidity. Ž5. Recurrence of primary liver disease. The diagnosis of recurrent disease in the allograft has been a matter of controversy. The diseases at risk of recurrence are: primary biliary cirrhosis ŽPBC., autoimmune hepatitis ŽAIH., primary sclerosing cholangitis ŽPSC., HCV- and HBV-related disease. Recurrence of primary biliary cirrhosis ŽPBC. in liver allografts remains a controversial issue. Sebagh et al. w17x evaluated this risk and tried to determine the presence, if any, of a predictive histological feature. They reviewed the most recent and the 1-year protocol liver biopsies of 69 patients who received transplants for PBC vs. 53 control patients. Histological features consistent with PBC recurrence included non-suppurating destructive cholangitis, mixed portal infiltrate, fibrosis, and ductopenia. A complete evaluation was undertaken in each patient with these histological features, which occurred in six patients who received transplants for PBC Ž8.7% vs. 0% in the control group. from 1 to 8 years after transplantation. In five of the six patients, anti-mitochondrial-2 Žanti-M2. antibodies remained at high titers. Cholestasis was present in four patients, and clinical symptoms in two. All six patients were negative for HCV and HCV-RNA in their serum. None had bile duct obstruction. The presence of plasma cells in the portal infiltrate at 1 year after the transplant was predictive of this risk of recurrence. The risk of PBC recurrence is real Ž8.7%.. AIH may recur after liver transplantation and it is difficult to diagnose. Ayata et al. w18x defined the histopathology and factors related to AIH recurrence. Fourteen of 475 patients received LT for AIH; two died perioperatively. Liver specimens Žnative and post-transplant biopsies. from 12 other patients were reviewed and correlated with pre- and post-transplant clinical course and outcome. Recurrent AIH was seen in 5 of 12 patients, 35 to 280 days post-trans-
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plant as lobular hepatitis with acidophil bodies and lymphoplasmacytic infiltrate. Portalrinterface hepatitis was seen with disease progression and two of five patients developed cirrhosis. Of seven non-recurrent patients, one had acquired hepatitis C with lobularrportal hepatitis and none developed cirrhosis. Histology suggestive of overlap syndrome was seen in 3 of 12 native livers with no effect on post-transplant course or pathology. High-grade necro-inflammation was present in native livers at transplant in five of five cases with recurrent AIH and in one of seven without recurrence Ž P - 0.01.. Pre-transplant disease duration, donorrrecipient gender distribution, HLA studies, and rejection episodes did not correlate with AIH recurrence. The authors conclude that Ž1. recurrent AIH is not uncommon and was seen in 42% of patients with lymphoplasmacytic lobular, portal, and interface hepatitis; Ž2. acidophil bodies with lymphoplasmacytic cells are seen in early recurrent AIH; Ž3. recurrent AIH appears at variable times post-LT, and its progression is slow; Ž4. high-grade inflammation in native liver at LT is a strong predictor of recurrent AIH. Fibro-obliterative lesions and fibrous cholangitis are characteristic histological lesions of primary sclerosing cholangitis. To determine whether such lesions can be found in the liver allograft, and whether they represent recurrent disease, Harrison et al. w19x reviewed all consecutive histological material taken more than 6 months after transplantation in a 3-year period from a series of 207 liver transplantations Ž22 with primary sclerosing cholangitis, 185 controls without primary sclerosing cholangitis.. Because patients with primary sclerosing cholangitis have a biliary system reconstructed by means of a Roux loop, they compared the findings with those from a further control group of patients who had received a Roux loop for reasons other than primary sclerosing cholangitis. Of 22 patients receiving liver transplants for primary sclerosing cholangitis, 7 Ž32%. patients had biopsy specimens showing features of biliary obstruction, 6 Ž27%. showed fibrous cholangitis, and 3 Ž14%. showed classic fibro-obliterative lesions. These findings compared with 3 Ž14%., 1 Ž5%. and 0 of the 22 Roux controls, and 19 Ž10%., 4 Ž2%. and 0 of the 185 controls without primary sclerosing cholangitis, respectively. The three patients with fibro-obliterative lesions either had clinical episodes
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of cholangitis or had micro-organisms in the large bile ducts. However, both biliary obstructive features and fibrous cholangitis were more common in primary sclerosing cholangitis, and fibro-obliterative lesions were only found in patients who received transplants for primary sclerosing cholangitis, despite the presence of cholangitis and Roux loops in control patients. The time progression of allograft damage in patients with recurrent hepatitis C after orthotopic liver transplantation has not been precisely determined. Testa et al. w20x analysed the progression of disease recurrence and its impact on patient and graft survival. Data on 300 patients who underwent transplantation for hepatitis C were analyzed regarding the incidence of histological recurrence, risk factors, immunosuppressive regimen, rejection episodes, and survival. For patients with histological recurrence, the timing and risks for disease progression were analyzed. Data on 30 patients who underwent retransplantation were studied. Histological recurrence occurred in 40.3% of patients, 27.2% of whom progressed to bridging fibrosis or cirrhosis. Eighty-seven percent of the patients experienced recurrence of disease within 24 months of transplantation. Patients with histological recurrence within 6 months of liver transplantation had a greater risk for progression to cirrhosis than patients recurring later on Žrisk ratio, 2.3.. Recurrence within 1 year was associated with decreased patient and graft survival rates at 1 and 5 years Ž65.1% and 56.4% vs. 80.6% and 78.4%; P s 0.004 and P s 0.0008, respectively.. Patients with histological recurrence had a greater incidence of acute cellular rejection, as well as multiple episodes of rejection, steroid-resistant rejections, and greater cumulative doses of corticosteroids. Demetris et al. w21x evaluated the morphologic evolution of hepatitis B virus ŽHBV. liver disease in 45 hepatic allograft recipients who were HBV surface-antigen positive ŽHBs-Agq . at the time of liver replacement and who survived for more than 60 days. They were studied by routine histological and immunocytochemical analysis of serial pathology specimens. The findings in these patients were compared to a control group of 30 individuals who were immune to the HBV Žanti-HBs antibody positive., but required hepatic replacement for other reasons. Eight of the 45 Ž18%. HBsAg-positive patients had
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no serologic evidence of HBV re-infection after transplantation. All 37 remaining patients were re-infected; 21 Ž47%. developed chronic active hepatitis andror cirrhosis, 3 Ž7%. developed submassive necrosis, and 6 Ž14%. developed chronic lobular hepatitis. One patient lost her graft to chronic rejection, despite re-infection with the B virus. Four other patients Ž9%. developed a chronic carrier status. No long-term follow-up biopsies were available in the remaining two patients. The histological features associated with dysfunction related to recurrent HBV infection evolved from an acute to chronic phase and were similar to hepatitis B seen in non-allografted livers. Furthermore, HBV-related lesions could be separated from rejection using routine histology alone. The only exception to this conclusion was the occurrence of a peculiar HBV-related lesion in two recipients. Immunohistochemical analysis demonstrated the presence of viral antigens in almost all cases. Hepatic inflammation was also commonly present in HBV disease and consisted mostly of accessory cells and T lymphocytes. Analysis of the effect of major histocompatibility complex matching revealed no clear association between the number of class I or II matches or mismatches and the development, or pattern, of active hepatitis in the allograft. Peculiar pathological alterations in several of the biopsies and failed allografts after HBV re-infection suggest that, under certain circumstances, the B virus may be cytopathic.
4. Conclusion Morphological monitoring of graft function following liver transplantation relies mainly on histopathological evaluation since liver biopsy is the gold standard to make the diagnosis of hepatic damage. Biochemical andror instrumental examinations should be performed to complete the clinical assessment in the early- and long-term liver function follow-up.
References w1x Smith CM, Davies DB, McBride, MA. Liver transplantation in the United States: a report from the UNOS Liver Transplant Registry Clinical Transplantation 1999;23–34.
w2x Mokowka L, Gordon RD, Todo S, et al. Analysis of donor criteria for the prediction of outcome in clinical liver transplantation. Transplant Proc 1987;19:2378–82. w3x Howard TK, Klintman GB, Cofer JB, Husberg BS, Goldstein RM, Gonwa TA. The influence of preservation injury on rejection in the hepatic transplant recipient. Transplantation 1990;49:103–7. w4x Ploeg RJ, D’Alessandro AM, Knechtle SJ, et al. Risk factors for primary dysfuncion after liver transplantation: a multivariate analysis. Transplantation 1993;55:807–13. w5x Gonzalez FX, Rimola A, Grande L, et al. Predictive factors of early postoperative graft function in human liver transplantation. Hepatology 1994;20:565–73. w6x Strasberg SM, Howard TK, Molmenti EP, Hertl M. Selecting the donor liver: risk factors for poor function after orthotopic liver transplantation. Hepatology 1994;20:829–38. w7x Deschenes M, Belle SH, Krom RAF, Zetterman RK, Lake JR. Early allograft dysfunction after liver transplantation. Transplantation 1998;66Ž3.:302–10. w8x Igea J, Nuno J, Lopez-Hervas P, et al. Evaluation of glycolytic parameters and cytoplasmatic redox status as markers of hepatic function in liver transplantation. Transplant Proc 1999;31:2443–4. w9x Nakatani T, Ozawa K, Asano M, Ukikusa M, Kamiyama Y, Tobe T. Changes in predominant energy substrate after hepatectomy. Life Sci 1981;28Ž3.:257–64. w10x Boros P, Suehiro T, Curtiss S, et al. Differential contribution of graft and recipient to perioperative TNF-alpha, IL-1 beta, IL-6 and IL-8 levels and correlation with early graft function in clinical liver transplantation. Clin Transplant 1997;11: 588–92. w11x Neuberger J, Wilson P, Adams D. Protocol liver biopsies: the case in favour. Transplant Proc 1998;30:1497–9. w12x Tung BY, Kimmey MB. Biliary complications of orthotopic liver transplantation. Dig Dis Sci 1999;17Ž3.:133–44. w13x Ikeda T, Yanaga K, Kishikawa K, Kazikoe S, Shimada M, Sugimachi K. Ischemic injury in liver transplantation: difference in injury site between warm and cold ischemia in rats. Hepatology 1992;16Ž2.:454–61. Aug. w14x Batts KP. Acute and chronic hepatic allograft rejection: pathology and classification. Liver Transplant Surg 1999; 5Ž4.:S21–9. Suppl. 1. w15x Burra P, Chirizzi L, Cadrobbi R, et al. Evaluation of liver function and morphology following ischemia-reperfusion injury in pigs. Transplant Proc 1997;29:3515–7. w16x Lamps LW, Pinson CW, Rainford DS, Shyr Y, Scott MA, Washington MK. The significance of microabscesses in liver transplant biopsies: a clinicopathological study. Hepatology 1998;28Ž6.:1532–7. Dec. w17x Sebagh M, Farges O, Dubel L, Samuel D, Bismuth H, Reynes M. Histological features predictive of recurrence of primary biliary cirrhosis after liver transplantation. Transplantation 1998;65Ž10.:1328–33. w18x Ayata G, Gordon FD, Lewis WD, et al. Liver transplantation for autoimmune hepatitis: a long-term pathologic study. Hepatology 2000;32Ž2.:185–92. w19x Harrison RF, Davies MH, Neuberger JM, Hubscher S. Fibrous and obliterative cholangitis in liver allograft: evidence
F.P. Russo et al.r Clinica Chimica Acta 310 (2001) 17–23 of recurrent primary sclerosing cholangitis? Hepatology 1994;20Ž2.:356–61. w20x Testa G, Crippin JS, Netto GJ, et al. Liver transplantation for hepatitis C: recurrence and disease progression in 300 patients. Liver Transplant 2000;6Ž5.:553–61.
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w21x Demetris AJ, Todo S, Van Thiel DH, et al. Evaluation of hepatitis B virus liver disease after hepatic replacement. Practical and theoretical considerations. Am J Pathol 1990;137Ž3.:667–76.