The use of hepatitis C viral RNA levels in liver tissue to distinguish rejection from recurrent hepatitis C

Quantification of C4d deposition and hepatitis C virus RNA in tissue in cases of graft rejection and hepatitis C recurrence after liver transplantation

Histology is the gold standard for diagnosing acute rejection and hepatitis C recurrence after liver transplantation. However, differential diagnosis between the two can be difficult. We evaluated the role of C4d staining and quantification of hepatitis C virus (HCV) RNA levels in liver tissue. This was a retrospective study of 98 liver biopsy samples divided into four groups by histological diagnosis: acute rejection in patients undergoing liver transplant for hepatitis C (RejHCV+), HCV recurrence in patients undergoing liver transplant for hepatitis C (HCVTx+), acute rejection in patients undergoing liver transplant for reasons other than hepatitis C and chronic hepatitis C not transplanted (HCVTx-). All samples were submitted for immunohistochemical staining for C4d and HCV RNA quantification. Immunoexpression of C4d was observed in the portal vessels and was highest in the HCVTx- group. There was no difference in C4d expression between the RejHCV+ and HCVTx+ groups. However, tissue HCV RNA levels were higher in the HCVTx+ group samples than in the RejHCV+ group samples. Additionally, there was a significant correlation between tissue and serum levels of HCV RNA. The quantification of HCV RNA in liver tissue might prove to be an efficient diagnostic test for the recurrence of HCV infection.

Clinical value and safety of liver biopsies in patients transplanted for hepatitis C virus-related end-stage liver disease

BACKGROUND

Hepatitis C is the leading indication for liver transplantation. Differentiation between recurrent graft hepatitis C (RGH-C) and graft rejection (GR) is challenging. Liver biopsy is standard to diagnose both conditions; however, little information is available regarding this procedure in hepatitis C virus (HCV)-infected liver transplant recipients.

METHODS

Liver biopsies (n = 211) from all consecutive patients (n = 138) transplanted for hepatitis C at Hannover Medical School between January 2000 and October 2011 were screened, and a final cohort of 96 patients with 196 biopsies was included. Indications, histopathological findings, and biopsy-related complications were documented. Modifications in the treatment based on the biopsy result and the biochemical outcome were analyzed.

RESULTS

Most biopsies (196/211, 93%) were representative. Five patients (2.5%) developed non-fatal biopsy-related complications. Biopsy results were GR (35%), RGH-C (31%), and other diagnoses (34%). GR was independently associated with lower albumin (P = 0.025) and higher bilirubin levels (P = 0.011). Treatment was modified based on the biopsy result in 25% of cases. Alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), and bilirubin levels improved in 41%, 25%, and 31% of cases 4 weeks post biopsy respectively. ALT improvements were more significant in patients with GR than in those with RGH-C.

CONCLUSION

Liver biopsy in HCV-infected liver transplant recipients is safe and representative in >90% of cases. GR is independently associated with lower albumin and higher bilirubin levels.

Recurrent hepatitis C and acute allograft rejection: clinicopathologic features with emphasis on the differential diagnosis between these entities

Chronic hepatitis C virus infection is the leading etiology for liver transplantation in the United States. Recurrent hepatitis C occurs nearly universally in these patients and represents a serious posttransplantation complication. Despite the detailed characterization of the histologic features of both recurrent hepatitis C and acute cellular rejection (ACR) over the last decades, the pathologic distinction between these 2 conditions remains one of the greatest diagnostic challenges in liver pathology. An accurate diagnosis, nevertheless, plays an essential role in patient management, as different therapeutic strategies are used for these conditions. In this review, the clinicopathologic features of posttransplantation recurrent hepatitis C and ACR are discussed, with emphasis on distinguishing histopathologic features, morphologic variants, ancillary techniques, and diagnostic pitfalls.

ELISA-based detection of C4d after liver transplantation--a helpful tool for differential diagnosis between acute rejection and HCV-recurrence?

Hepatitis-C is the most common indication for liver transplantation. Recurrence of HCV is universal leading to graft failure in up to 40% of all patients. The differentiation between acute rejection and recurrent hepatitis-C is crucial as rejection treatments are likely to aggravate HCV-recurrence. Histological examination of liver biopsy remains the gold standard for diagnosis of acute rejection but has failed in the past to distinguish between acute rejection and recurrent hepatitis-C. In a retrospective study we have recently reported that C4d as a marker of the activated complement cascade is detectable in a hepatic specimen in acute rejection after liver transplantation and may serve as a valuable tool in differential diagnosis between ACR and HCV-recurrence. We performed a prospective analysis by ELISA measurement of C4d concentration in cryo-preserved liver biopsies of LTX patients who had either experienced acute rejection, hepatitis-C recurrence or displayed no pathological alterations (controls). Opposed to our immunohistologically based findings in paraffinized tissue we were unable to detect significant differences of C4d concentration in ELISA of cryo-preserved liver tissue. Consequently the role and potential value of C4d as a diagnostic marker may not be determined using ELISA-based tissue evaluation.

Real-time quantitative assay for routine testing of HCV RNA in formalin-fixed, paraffin-embedded liver samples

The assessment of hepatitis C virus (HCV) RNA in liver tissues is clinically relevant in cases where histology, liver function tests, and HCV serology are not sufficient for a definitive diagnosis of HCV-related hepatitis. We analyzed 215 formalin-fixed, paraffin-embedded liver needle biopsies from patients infected with HCV genotypes 1b and 2. HCV RNA extracted from paraffin sections were quantified by means of a TaqMan real-time reverse transcription-polymerase chain reaction method. The quantification of HCV RNA in liver tissue was correlated with the amount of HCV detected by immunohistochemistry (IHC) on paired frozen biopsies, the HCV RNA load in the serum, and the main serum tests of liver function and cholestasis. HCV RNA was detected by real-time reverse transcription-polymerase chain reaction in 169 liver biopsies (78.6%) with a mean value of 13.59+/-37.25 IU/ng. Tissue HCV RNA levels strongly correlated with the IHC results (P<0.001, Spearman test), HCV serum load (P<0.001), aspartate aminotransferase (P=0.001), gamma-glutamyl transpeptidase (P=0.012), and aspartate aminotransferase/alanine aminotransferase ratio (P=0.029). HCV RNA was amplified in up to 7-year-old archival tissue samples. Real-time HCV RNA quantification on archival liver tissue may be clinically relevant in case of "occult" HCV infection or for the diagnosis of patients with known HCV infection and hepatic dysfunction but seronegative for HCV RNA. The assessment of the levels of HCV RNA in the liver might also be important for monitoring the effectiveness of antiviral therapy and the progression of disease in patients with chronic HCV hepatitis.

Immunohistochemical staining of liver grafts with a monoclonal antibody against HCV-Envelope 2 for recurrent hepatitis C after living donor liver transplantation

AIM

We evaluated the expression of hepatitis C virus (HCV) antigen on liver grafts by immunohistochemical staining (IHS) using IG222 monoclonal antibody (mAb) against HCV-envelope 2 (E2).

METHODS

The study material was 84 liver biopsy specimens obtained from 28 patients who underwent living donor liver transplantation (LDLT) for HCV infection. The biopsy samples were examined histopathologically, and by IHS using IG222 mAb against HCV-E2. Serum HCV-RNA level was measured in all patients. The IHS grades were compared among the three groups classified according to the time elapsed from LDLT (at 1-30, 31-179 and > or =180 days post-LDLT) and among four post-transplant conditions, including acute cellular rejection (ACR).

RESULTS

Immunoreactivity to IG222 was detected in 78.6% of the specimens obtained during the first month after LDLT, and there were no significant differences on the IHS grades between the three groups classified according to the time elapsed from LDLT. The IHS grades were significantly stronger in definite recurrent HCV (n = 12) and probable recurrent HCV (n = 7) than in definite ACR (n = 7) and other complications (n = 8). There were no significant differences in serum HCV-RNA levels among the four post-transplant conditions. There was no significant correlation between the IHS grades using IG222 mAb and serum HCV-RNA levels when data of 84 liver biopsy specimens were analyzed.

CONCLUSIONS

Constant HCV-E2 expression was observed in liver biopsy specimens obtained 1 month or longer. The strong HCV-E2 expression on liver grafts were associated with recurrent hepatitis C after LDLT, but the serum HCV-RNA levels were not.

Minichromosome maintenance protein-2-positive portal tract lymphocytes distinguish acute cellular rejection from hepatitis C virus recurrence after liver transplantation

Hepatitis C virus (HCV) is a leading indication for liver transplantation worldwide, but graft infection with HCV frequently leads to hepatic fibrosis. Acute cellular rejection (ACR) can be difficult to distinguish confidently from HCV, even with histology, but accurate diagnosis is critical because treatment of ACR may accelerate HCV-related graft injury. Immunohistochemistry was undertaken on 99 liver biopsies from 31 patients with HCV graft infection, 22 patients with ACR, and 11 patients with HCV infection and unexplained graft dysfunction to investigate whether lymphocyte expression of minichromosome maintenance protein-2 (Mcm-2), a marker of licensed cell cycle entry, assessed in a novel semiautomated system could distinguish between ACR and graft infection with HCV. The portal tract area was greater in ACR than in HCV graft infection (P = 0.027), but there was considerable overlap. However, both the number of Mcm-2-positive lymphocytes per portal tract and the number of Mcm-2-positive lymphocytes per millimeter squared of portal tract distinguished between ACR and HCV graft infection (P < 0.0001). A cutoff value of 107 positive cells per portal tract had a sensitivity of 81.8% and a specificity of 91.9% (positive predictive value of 66.67% and negative predictive value of 95.75%). Of 11 HCV-infected patients with an uncertain diagnosis, 7 were deemed ultimately to have HCV graft infection, and 4 had superimposed corticosteroid-responsive ACR. The number of Mcm-2-positive cells per portal tract and per millimeter squared of portal tract again distinguished clearly between the groups (P = 0.012). In conclusion, lymphocyte Mcm-2 expression is a useful adjunct to histology in differentiating between HCV graft infection and ACR. Patients with a low number of Mcm-2-positive portal tract lymphocytes are less likely to have ACR.

Tissue hepatitis C virus RNA quantification and protein expression help identify early hepatitis C virus recurrence after liver transplantation

We compared tissue hepatitis C virus (HCV) RNA polymerase chain reaction quantification and HCV immunohistochemistry (IHC) to histology in biopsy tissues in order to differentiate between acute rejection and HCV hepatitis recurrence early after orthotopic liver transplantation (OLT). We analyzed the first biopsy performed because of alteration of serum aminotransferases in 65 consecutive OLT patients with HCV genotype 1b. In the histological analysis, we quantified the portal tracts, Councilman bodies, Councilman body/portal tract (CP) ratio, steatosis, and Knodell and Ishak scores. The 52 patients (80%) with histological HCV recurrence [recurrence-positive (Rec+)] were separated from the 6 (9%) with acute rejection and the 7 (11%) with undetermined pathological features [recurrence-negative (Rec-)]. HCV RNA strongly correlated with HCV IHC, regardless of the histological diagnosis (P < 0.001). Both HCV RNA and HCV IHC were significantly associated with CP ratio (P = 0.041 and P = 0.008). No statistical correlation was found between HCV RNA, HCV IHC, and the other histopathologic features or the hepatitis scores. HCV RNA, HCV IHC, and CP ratio were the only variables able to discriminate between Rec+ and Rec- patients (Mann-Whitney test P < 0.001, P < 0.001, P = 0.014). In conclusion, a combined evaluation of histology, tissue HCV RNA, and HCV IHC significantly discriminated between OLT patients with or without HCV recurrence.

[Clinical outcome after living donor liver transplantation in patients with hepatitis C virus-associated cirrhosis]

BACKGROUND AND AIMS

Hepatitis C virus (HCV)-associated cirrhosis is an increasingly frequent indication for liver transplantation (LT). However, HCV recurrence is universal and this immediately occurs following LT, which endangers both the graft and patient survival. We investigated the frequency of posttransplant recurrence of HCV infection and the patient-graft survival, and we analyzed the responses to ribavirin and interferon therapy in the patients with recurrent HCV infection after living donor liver transplantation (LDLT).

METHODS

We retrospectively reviewed the clinical outcomes of 39 HCV-associated cirrhosis patients who underwent LDLT at Asan Medical Center between August 1992 and June 2006. In this study, the diagnosis of recurrent HCV was made on the basis of increased transaminases and serum HCV RNA levels greater than 10 million IU/mL because protocol liver biopsy was not performed.

RESULTS

HCV recurrence was seen in 26 of the 39 LDLT patients (66.7%). 86.7% of recurrence occurred within the first postoperative year. Antiviral treatment was used for all patients with recurrence of HCV. None of the 10 patients receiving ribavirin alone and 9 of 16 patients who received combination therapy with pegylated interferon alpha-2a plus ribavirin became HCV RNA negative and they remained persistently negative during the median follow-up of 24.9 months. Our data indicates that there is no significant factor influencing HCV recurrence except for the recipient's age. The 2-year patient survival for the HCV patients with HCC and those patients without HCC were 81.2% and 81.3%, respectively (P=0.85) and the 2-year graft survival rates were 81.2% and 68.2%, respectively (P=0.29). No patient died from HCV recurrence during the follow-up period.

CONCLUSIONS

Combination therapy with ribavirin and interferon appears to improve the outcome of recurrent HCV infected patients after LDLT.

Blood eosinophilia after living donor liver transplantation for hepatitis C virus-related cirrhosis

BACKGROUND

Differentiating between acute cellular rejection (ACR) and recurrent hepatitis C virus after liver transplantation in hepatitis C virus-positive patients is difficult, but vital for preventing graft loss.

METHODS

The blood eosinophil counts 3 days before or on the day of biopsy were retrospectively reviewed to evaluate their value for predicting ACR in 91 biopsy samples from 45 patients.

RESULTS

Eosinophil counts on the day of biopsy were significantly higher in the ACR group (n = 20) than in the non-ACR (n = 71) group, although the difference was negligible 3 days before the biopsy. A relative eosinophil count of 2% or an absolute eosinophil count of 200 cells/mm(3) predicted ACR with a specificity of 94% or 96%, respectively.

CONCLUSIONS

Blood eosinophil count on the day of biopsy can be helpful in the diagnosis of ACR in patients who underwent living donor liver transplantation for hepatitis C virus-related cirrhosis.

Acute rejection in HCV-infected liver transplant recipients: The great conundrum

1. In hepatitis C virus (HCV)-infected patients, treatment of acute rejection is associated with worse outcomes (increased risk of allograft cirrhosis and mortality). 2. Whether patients with HCV are at higher risk for rejection remains controversial. 3. The mechanisms mediating acute rejection and recurrence of HCV are distinct, and as such, it should be possible to develop techniques based on these molecular differences that are diagnostically useful. 4. Liver biopsy is considered the gold-standard for diagnosing acute rejection and recurrent HCV; however, given histopathological similarities between the two conditions, discrimination can be extremely difficult. 5. At the present time, there are no reliable, noninvasive tools available to distinguish between HCV recurrence alone and acute rejection plus HCV recurrence. 6. Mild rejection per se is not associated with graft loss and treatment of rejection with steroids and OKT3 is associated with worse outcome in HCV; thus, it seems logical that we should no longer treat mild rejection.

Detection of HCV antigens in liver graft: relevance to the management of recurrent post-liver transplant hepatitis C

The aim of this study was to evaluate how the immunohistochemical detection of liver hepatitis C virus (HCV) antigens (HCV-Ag) could support the histologic diagnosis and influence the clinical management of post-liver transplantation (LT) liver disease. A total of 215 liver specimens from 152 HCV-positive patients with post-LT liver disease were studied. Histologic coding was: hepatitis (126), rejection (34), undefined (24; coexisting rejection grade I and hepatitis), or other (31). The percentage of HCV-Ag infected hepatocytes were evaluated, on frozen sections, by an immunoperoxidase technique. HCV-Ag were detectable early in 57% of cases within 30 days post-LT, 92% of cases between 31 and 180 days, and 74% of cases after more than 180 days. Overall, HCV-Ag were detected more frequently in histologic hepatitis as compared to rejection (P < 0.0001) with a higher percentage of positive hepatocytes (P < 0.00001). In 16 patients with a high number of HCV-Ag-positive hepatocytes (65%; range 40-90%) a clinical diagnosis of recurrent hepatitis (RHC) was made despite inconclusive histopathologic diagnosis. Multivariate analysis identified the percentage of HCV-Ag-positive hepatocytes and the time post-LT as independent predictors for RHC (P = 0.008 and P = 0.041, respectively) and the number of HCV-Ag-positive hepatocytes >/=50% as the only independent predictor for nonresponse (P < 0.001) in 26 patients treated with alpha-interferon plus ribavirin. In conclusion, HCV reinfection occurs early post-LT, reaching its peak within 6 months. Immunohistochemical detection of post-LT HCV reinfection support the diagnosis of hepatitis when the histologic features are not conclusive. A high number of infected cells, independently from the genotype, represents a negative predictive factor of response to antiviral treatment.

HBV and HCV infections and acute rejection differentially modulate CD95 and CD28 expression on peripheral blood lymphocytes after liver transplantation

Hepatitis B virus (HBV) and hepatitis C virus (HCV) generally reinfect liver graft early posttransplantation and lead to poorer graft and patient survivals. In the present study the influence of acute rejection (AR), HBV and HCV infections, and human leukocyte antigen (HLA) class-I compatibility on the expression of CD28 (in 237 liver recipients) and CD95 (in 114 liver recipients) on peripheral blood cells were evaluated by flow cytometry during the first month after transplantation. HBV/HCV infections induced strong CD95 upregulation on CD3+ lymphocytes. Maximal CD95 upmodulation was found in infected recipients showing partial HLA class-I compatibility. AR and virus reinfection could be distinguished because CD28 was upregulated on CD4+ lymphocytes only in recipients with AR, irrespective of their status regarding HBV/HCV infections. In conclusion, cytometric co-evaluation of CD95 and CD28 expression on peripheral blood lymphocytes could be useful to discriminate AR from cellular activation induced by viral reinfection of the liver graft.

C4d in acute rejection after liver transplantation--a valuable tool in differential diagnosis to hepatitis C recurrence

Hepatitis C is the most common indication for liver transplantation. Recurrence of HCV is universal leading to graft failure in up to 40% of all patients. The differentiation between acute rejection and recurrent hepatitis C is crucial as rejection treatments are likely to aggravate HCV recurrence. Histological examination of liver biopsy remains the gold standard for diagnosis of acute rejection but has failed in the past to distinguish between acute rejection and recurrent hepatitis C. We have recently reported that C4d as a marker of the activated complement cascade is detectable in hepatic specimen in acute rejection after liver transplantation. In this study, we investigate whether C4d may serve as a specific marker for differential diagnosis in hepatitis C reinfection cases. Immunohistochemical analysis of 97 patients was performed. A total of 67.7% of patients with acute cellular rejection displayed C4d-positive staining in liver biopsy whereas 11.8% of patients with hepatitis C reinfection tested positive for C4d. In the control group, 6.9% showed C4d positivity. For the first time we were able to clearly demonstrate that humoral components, represented by C4d deposition, play a role in acute cellular rejection after LTX. Consequently C4d may be helpful to distinguish between acute rejection and reinfection after LTX for HCV.

Low Incidence of Acute Rejection after Living-Donor Liver Transplantation: Immunologic Analyses by Mixed Lymphocyte Reaction using a Carboxyfluorescein Diacetate Succinimidyl Ester Labeling Technique

BACKGROUND

To monitor antidonor alloreactivity for accurate diagnosis of acute rejection after living-donor liver transplantation (LDLT), we used a mixed lymphocyte reaction (MLR) assay using an intracellular fluorescent dye carboxyfluorescein diacetate succimidyl ester (CFSE)-labeling technique (CFSE-MLR) in 29 consecutive patients who underwent adult-to-adult LDLT.

METHODS

For patients who developed moderate or severe disorders in liver function, CFSE-MLR was performed together with needle biopsy of the liver allografts immediately after liver dysfunction had occurred. CFSE-labeled peripheral blood mononuclear cells (PBMC) from recipients and irradiated autologous, donor, or third-party PBMC were cultured, and then proliferation and CD25 expression in each of the CD4+ and CD8+ T cell subsets were analyzed by flow cytometry.

RESULTS

Twelve (41.4%) of the 29 patients developed moderate or severe disorders in liver function within 6 months after LDLT. Eight of the 12 patients (overall incidence of 27.6%) suffering from liver function disorder were diagnosed on the basis of liver biopsy results as having mild or moderate acute rejection. However, only 4 of the 12 patients (overall incidence of 13.8%) showed remarkable proliferation of CD8+ T cells in association with CD25 expression on antidonor CFSE-MLR. The other eight patients were eventually diagnosed as having recurrence of original hepatitis, drug-induced hepatotoxicity, or congestion of the anterior segment of the liver allograft by further extensive examinations or in retrospect.

CONCLUSIONS

The results of CFSE-MLR assays, which could be used for rigorously monitoring rejection, provided evidence of low incidence of acute rejection after LDLT.

Reliability of histopathologic assessment for the differentiation of recurrent hepatitis C from acute rejection after liver transplantation

Histopathologic assessment is considered essential for the differentiation of recurrent hepatitis C (RHC) from acute cellular rejection (ACR) after liver transplantation (LT); however, there is limited information regarding its reliability. The aim of this study was to determine the interobserver and intraobserver agreement of the histopathologic diagnosis of RHC vs. ACR, and to determine the reliability of specific histopathologic features for the differentiation of RHC from ACR. Liver biopsy specimens from 105 consecutive patients transplanted for hepatitis C virus (HCV)-related liver disease were studied retrospectively. All the biopsies were performed for evaluation of abnormal liver enzymes within the 1st year after LT. The slides were blindly coded and assessed by 5 liver-transplant pathologists, practicing at 3 medical centers. The pathologists were asked to render a diagnosis, and determine the severity of the disease. Four of the pathologists were asked to determine the presence and severity of 36 histopathologic features. A total of 34 of the samples were then blindly resubmitted to each of the 4 pathologists to determine the intraobserver agreement. There was a slight agreement (kappa = .12) among the 5 pathologists on the histopathologic diagnosis. All 5 pathologists were in agreement on the diagnosis of RHC in only 5 patients (5%) and on the diagnosis of ACR in only 2 patients (2%). The best agreement among any 4 pathologists was fair (kappa = .20). Slight to moderate agreement occurred on the main histological features considered to be important in the diagnosis of ACR. Intraobserver agreement ranged from slight (kappa = .19) to moderate (kappa = .42) among 4 pathologists. In conclusion, the histopathologic differentiation of RHC from ACR after LT had relatively low interobserver and intraobserver agreement rates, and hence showed low reliability. Histopathologic assessment should be used cautiously for the differentiation of RHC from ACR post-LT.

Outcomes of acute rejection after interferon therapy in liver transplant recipients

Interferon alfa has been increasingly used against recurrent hepatitis C (HCV) disease in post-liver transplant (LT) recipients. A serious potential adverse effect is acute rejection. We reviewed our experience using interferon-based therapy (interferon or pegylated interferon with or without ribavirin) for treating recurrent HCV in LT recipients. Forty-four LT recipients were treated with interferon for recurrent HCV. Five of the 44 patients developed acute rejection during interferon-based therapy. These 5 patients started treatment of 42.4 +/- 33.89 months (mean +/- SD) after LT. Mean (+/- SD) histological activity index and fibrosis scores before initiating antiviral therapy were 8.8 (+/- 1.92) and 2.6 (+/- 0.55), respectively. Patients were treated for 3.3 +/- 2.28 months (mean +/- SD) prior to rejection. At the time of rejection, HCV load was not detectable in 4 of the 5 recipients. All 5 patients had tolerated interferon therapy, and none had stopped therapy because of adverse effects. The rejection was successfully treated in 3 patients. In 2 of those 3 patients, cirrhosis eventually developed. In the 2 patients who did not respond to rejection treatment, immediate graft failure occurred, leading to re-LT in 1 patient and death from sepsis in the other. In conclusion, the results indicate that further studies are needed to assess the safety of interferon in LT recipients. Interferon-based therapy may lead to acute rejection and subsequent graft loss and should therefore be used with caution. Treated recipients may also develop progressive cirrhosis despite achieving a sustained virological response.

Recurrent Hepatitis C in Liver Allografts

RATIONALE AND DESIGN

The accuracy of a prospective histopathologic diagnosis of rejection and recurrent hepatitis C (HCV) was determined in 48 HCV RNA-positive liver allograft recipients enrolled in an "immunosuppression minimization protocol" between July 29, 2001 and January 24, 2003. Prospective entry of all pertinent treatment, laboratory, and histopathology results into an electronic database enabled a retrospective analysis of the accuracy of histopathologic diagnoses and the pathophysiologic relationship between recurrent HCV and rejection.

RESULTS

Time to first onset of acute rejection (AR) (mean, 107 days; median, 83 days; range, 7-329 days) overlapped with the time to first onset of recurrent HCV (mean, 115 days; median, 123 days; range, 22-315 days), making distinction between the two difficult. AR and chronic rejection (CR) with and without co-existent HCV showed overlapping but significantly different liver injury test profiles. One major and two minor errors occurred (positive predictive values for AR = 91%; recurrent HCV = 100%); all involved an overdiagnosis of AR in the context of recurrent HCV. Retrospective analysis of the mistakes showed that major errors can be avoided altogether and the impact of unavoidable minor errors can be minimized by strict adherence to specific histopathologic criteria, close clinicopathologic correlation including examination of HCV RNA levels, and a conservative approach to the use of additional immunosuppression. In addition, histopathologic diagnoses of moderate and severe AR and CR were associated with relatively low HCV RNA levels, whereas relatively high HCV RNA levels were associated with a histopathologic diagnosis of hepatitis alone, particularly the cholestatic variant of HCV.

CONCLUSIONS

Liver allograft biopsy interpretation can rapidly and accurately distinguish between recurrent HCV and AR/CR. In addition, the histopathologic observations suggest that the immune mechanism responsible for HCV clearance overlap with those leading to significant rejection.

The natural history and outcome of liver transplantation in hepatitis C virus-infected recipients

1. Recurrence of hepatitis C infection is universal and immediate after liver transplantation. 2. Graft and patient survival is reduced in liver transplantation recipients with recurrent hepatitis C virus infection compared with hepatitis C virus-negative recipients. 3. The natural history of chronic hepatitis C is accelerated after liver transplantation compared with nontransplantation chronic hepatitis C; 20% to 40% of patients progress to allograft cirrhosis within 5 years, compared with less than 5% of nontransplantation patients. 4. The rate of fibrosis progression is not uniform and may change over time. 5. The rate of progression from cirrhosis to decompensation is accelerated after liver transplantation. The rate of decompensation is >40% at 1 year and >60% at 3 years, compared with <5% and <10%, respectively, in immunocompetent patients. 6. The rate of progression from decompensation to death is also accelerated after liver transplantation. The 3-year survival is <10% after the onset of hepatitis C virus-related allograft failure, compared with 60% after decompensation in immunocompetent patients.

Immunosuppression in hepatitis B virus and hepatitis C virus transplants: special considerations

The management of the immunosuppression treatment must take account its consequences on viral replication. Such treatment operates on the emerging balance between the recurrence of the virus on the graft and the immune response of the host. Randomized and prospective trials are currently ongoing with the purpose of determining the opportunity and relevance of each immunosuppressive agent in the treatment. In HBV patients, good control of HBV reinfection by prophylactic strategies using HBIG, lamivudine, or both have decreased the impact of immunosuppression on HBV recurrence. In contrast, HCV recurrence is now a major problem. The mechanisms of viral recurrence need to be deepened thus requiring new studies. The absence of in vitro and in vivo systems to study HCV reinfection is a lack in the comprehension of the relation between HCV and immunosuppression. It will allow adapting the effectiveness of the immunosuppression treatment. The treatment's primary target is to avoid graft rejection, and its secondary objective is to limit the risk of viral recurrence.

Increasing serum levels of IgM anti-HCV are diagnostic of recurrent hepatitis C in liver transplant patients with ALT flares

Recurrent hepatitis and acute rejection share common features which make difficult for diagnosis in liver transplant hepatitis C virus (HCV) positive patients. We studied the usefulness of quantitative monitoring of HCV RNA and immunoglobulin (Ig)M anti-HCV in the differential diagnosis between recurrent hepatitis and acute rejection in 98 consecutive anti-HCV positive liver transplant patients. Aminotransferase levels, serum HCV RNA and IgM anti-HCV were measured at the time of transplantation and monthly thereafter. A liver biopsy (LB) was obtained when serum aminotransferase levels increased to twice or more than normal. During a mean follow-up of 16 months 86 aminotransferase flares were observed. Histology was compatible with recurrent hepatitis C in 44 cases and with acute rejection in 28, doubtful in 14. The fluctuations of HCV RNA serum levels were not significantly different in the three groups. Serum IgM anti-HCV levels increased (from negative to positive or with value variations > or = 0.18) in 36 of 44 cases with recurrent hepatitis C at the time of alanine aminotransferase (ALT) flare. IgM anti-HCV remained unchanged in all rejection cases (P < 0.001), but increased in 10 of 11 histologically doubtful cases that were diagnosed as hepatitis at the second LB. Increasing serum levels of IgM anti-HCV at the time of ALT flares are significantly associated with recurrent hepatitis C in liver transplant patients. The quantitative monitoring of IgM anti-HCV appears to be an additional diagnostic tool for distinguishing recurrent hepatitis C from acute graft rejection with a 100% specificity; 100% positive predictive value and 88.9% diagnostic accuracy.