Deficiency of BSEP in PFIC with hepatocellular malignancy.
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Bile Acids and Salts↗
Biomedical subjects
B C Portmann
Publications and source records attributed to B C Portmann.
Anti-interleukin 2 receptor antibodies and mycophenolate mofetil for treatment of steroid-resistant rejection in adult liver transplantation.
BACKGROUND: Steroid-resistant rejection (SRR) results in significant morbidity and mortality from the adverse effects of rescue therapy and in graft loss from chronic rejection. In our knowledge, the efficacy and safety of anti-interleukin (IL) 2r antibodies (daclizumab and basiliximab) for the treatment of SRR in adult liver transplantation has not previously been evaluated. METHODS: Twenty-five patients received either daclizumab or basiliximab as rescue therapy for SRR. Outcome and biochemical parameters were recorded before and after treatment with an anti-IL-2r antibody. RESULTS: The median time from transplantation to SRR was 25 days. Secondary immunosuppression included mycophenolate mofetil in 18 patients. Twelve patients (48%) had complete resolution of SRR. Aspartate transaminase levels normalized at a median of 37 days (range, 1-168 days). In 13 patients (52%) progressive hepatic dysfunction developed. Four of these patients received another transplant, and 6 patients had chronic rejection. Three patients died with graft failure. Of 16 patients with acute cellular rejection, 12 (75%) had resolution, 2 had chronic rejection, 1 required a repeat transplantation, and 1 died with graft failure. In contrast, all 9 patients with established chronic rejection in their pretreatment biopsy continued to have significant graft dysfunction, with 4 having persistent chronic graft dysfunction, 3 requiring repeat transplantation, and 2 dying with graft failure. CONCLUSION: Twelve (48%) of 25 patients who received an anti-IL-2r antibody because of SRR were successfully treated. All successfully treated patients had ongoing acute cellular rejection at liver biopsy (75%), whereas patients with histologic evidence of chronic rejection responded poorly.
Adolescent↗
Characteristics of autoimmune hepatitis in patients who are not of European Caucasoid ethnic origin.
BACKGROUND: Significant diversity in disease severity has been identified for autoimmune disorders among different ethnic groups but there is a lack of data on autoimmune hepatitis (AIH) in populations other than those of European Caucasoid (EC) or Japanese extraction. AIMS: To assess the clinical features, response to therapy, and eventual outcome in AIH patients of non-EC ethnicity. METHODS: A retrospective review of a regularly updated database of patients with AIH referred to liver outpatient clinics at King's College Hospital, London, since 1983. RESULTS: Twelve patients were identified (10 female; six African, five Asian, one Arabic; median age at presentation 30 years (range 12-58)) who satisfied international criteria for type 1 (11 cases) or type 2 (one case) AIH. Nine (75%) had cholestatic serum biochemistry and three (25%) had mild biliary changes on liver biopsy without definitive features of primary biliary cirrhosis or cholangiographic evidence of primary sclerosing cholangitis. Four showed a complete biochemical response to standard prednisolone with or without azathioprine therapy, three partial, and five no response. Four have required liver transplantation for intractable disease. By comparison with 180 EC patients with definite AIH attending during the same period, the non-EC patients were younger (p<0.05), presented with cholestatic biochemistry (p=0.014), and morphological biliary features more frequently (p<0.0005) and showed a poorer initial response to standard therapy (p<0.0005). CONCLUSIONS: Clinical expression of AIH in non-EC patients seems to differ in important respects from that in EC or Japanese patients. Management of such patients is challenging and may require alternative or more aggressive treatment strategies.
Adolescent↗
Randomized trial of lamivudine versus hepatitis B immunoglobulin for long-term prophylaxis of hepatitis B recurrence after liver transplantation.
BACKGROUND/AIMS: The long-term prophylaxis of hepatitis B after liver transplantation requires further optimization. In a randomized trial we investigated a regimen where the initially given hepatitis B immunoglobulin (HBIg) is replaced by long-term lamivudine treatment. METHODS: Twenty-four liver transplant recipients (all HBsAg-positive/HBV DNA-negative before transplantation), who had received HBIg for at least 6 months without HBV recurrence, were randomized to receive lamivudine (n = 12) or HBIg (n = 12) for 52 weeks. The efficacy criteria involved seronegativity for HBsAg and undetectable HBsAg/ HBcAg in the liver. RESULTS: Twenty-one of 24 patients completed the study without hepatitis B virus (HBV) recurrence (11 on HBIg, ten on lamivudine), while three patients became HBsAg-positive. Amongst those without HBV recurrence HBV DNA was detectable only by polymerase chain reaction, intermittently in serum and lymphocytes, and in liver specimens from six of eight patients receiving HBIg and five of seven receiving lamivudine. YMDD variant was found in four cases with no viral antigen expression. Eight patients continued lamivudine after the study and during an additional 6-22 months remained HBsAg-negative with normal graft function. CONCLUSIONS: Substitution of HBIg with lamivudine is effective for prevention of HBV recurrence in low-risk liver transplant recipients and offers a convenient and cost-effective alternative for long-term HBV prophylaxis.
Adult↗
Graft dysfunction mimicking autoimmune hepatitis following liver transplantation in adults.
In children, a type of graft dysfunction associated with autoimmune features has been described. We have identified 7 adult liver-transplant (LT) recipients from a series of over 1,000 consecutive transplant recipients who presented between 0.3 years and 7.2 years following transplantation with characteristic symptoms, autoantibody profiles, and histologic findings of autoimmune disease. The indications for transplantation were Ecstasy overdose, alcohol-related cirrhosis, primary sclerosing cholangitis (PSC) (2), primary biliary cirrhosis (PBC), hepatitis C cirrhosis, and cryptogenic cirrhosis. Two patterns of de novo autoantibody development were noted; anti-liver-kidney-microsome (LKM) antibody development at high titer in association with an aspartate transaminase (AST) > 500 and antinuclear (ANA) and antismooth muscle (AMA) antibody development at titers >1/80 with lower AST levels. All cases had elevated IgG. Liver biopsies showed changes of an autoimmune-type hepatitis with portal and periportal hepatitis in association with a marked infiltrate of plasma cells, lymphocytes, and bridging collapse. Two patients lost their grafts because of the disease. Patients were treated with reintroduction of steroids and azathioprine in cases in which it had been withdrawn. Major histocompatibility class I and II mismatching did not incur risk. Eight of 12 liver allografts were acquired from either DRB*0301- or DRB*0401-positive donors, and 4 recipients were DRB*0301-positive. This series illustrates that both symptoms and histologic findings of graft dysfunction compatible with autoimmune hepatitis (AIH) exist in adult LT recipients. Graft loss may be a consequence. This entity may represent a specific type of rejection that should currently be classified as "graft dysfunction mimicking autoimmune hepatitis."
Adult↗
Immunopathogenesis of hepatitis B virus recurrence after liver transplantation.
BACKGROUND AND AIMS: Hepatitis B virus (HBV) recurrence after orthotopic liver transplantation is associated with inflammatory graft changes, despite immunosuppression and donor/recipient HLA mismatch. We investigated whether immune mechanisms are involved in the pathogenesis of hepatitis B after liver transplantation. METHODS: The virus-specific T helper (Th) cell response, activation of Th1/Th2 subpopulations, donor/recipient HLA, and expression of tumor necrosis factor (TNF)-alpha/TNF receptors were determined in 28 patients who underwent transplantation for HBV-related cirrhosis (17 with HBV recurrence and 11 without recurrence) in comparison to 30 nontransplant patients with chronic hepatitis B. RESULTS: Orthotopic liver transplantation recipients with HBV recurrence showed significant hepatitis B core antigen-specific T-cell proliferation, comparable to nontransplant patients, which was not present in transplant recipients without recurrence. In addition, hepatic and serum interleukin (IL)-2, interferon-gamma, and TNF-alpha were enhanced, without changes in IL-4 and IL-10. Phenotypically, hepatic infiltrates in allografts with HBV recurrence were comprised of CD4+ lymphocytes and macrophages with a correlation between interferon-gamma- and TNF-alpha-producing cells and the degree of necroinflammatory activity. There was a marked up-regulation of both TNF-alpha receptors, significantly greater than in nontransplant patients. CONCLUSIONS: These findings suggest that despite immunosuppression, HLA class I-independent immune mechanisms have a significant pathogenic role in liver damage associated with HBV recurrence after liver transplantation.
Adult↗
The canals of Hering and hepatic stem cells in humans.
Small, extraportal, hepatic parenchymal cells, positive for biliary-type cytokeratins, may represent hepatic stem cells, canals of Hering (CoH), and/or ductal plate remnants. We evaluated these cells 3 dimensionally in normal human liver and massive necrosis. Tissues from normal human livers and from 1 liver with acetaminophen-induced massive necrosis were serially sectioned, immunostained for cytokeratin 19 (CK19), and sequentially photographed. Images were examined to determine 3-dimensional relationships among CK19-positive cells. Immunostains for other hepatocyte and progenitor cell markers were examined. In normal livers, intraparenchymal CK19-positive cells lined up as linear arrays in sequential levels. One hundred of 106 (94.3%) defined, complete arrays within levels examined, most having 1 terminus at a bile duct, the other in the lobule, beyond the limiting plate. In massive necrosis, there were 767 individual CK19-positive cells or clusters around a single portal tract, 747 (97.4%) of which were spatially related forming arborizing networks connected to the interlobular bile duct by single tributaries. C-kit was positive in normal CoH. CK19 co-expressed with HepPar1, c-kit, and alpha-fetoprotein (AFP) in parenchymal cells in massive necrosis. Small, extraportal, biliary-type parenchymal cells represent cross-sections of the CoH that radiate from the portal tract, usually extending past the limiting plate into the proximate third of the hepatic lobule. The 3-dimensional structure of ductular reactions in massive necrosis suggests that these reactions are proliferations of the cells lining the CoH. Therefore, the CoH consist of, or harbor, facultative hepatic stem cells in humans.
Acetaminophen↗
p53 mutations in british patients with hepatocellular carcinoma: clustering in genetic hemochromatosis.
BACKGROUND & AIMS: Environmental factors are important in the etiology of hepatocellular carcinoma (HCC). Aflatoxin B1 causes a specific point mutation in the p53 tumor-suppressor gene in exposed individuals. In Western populations, mutations of this gene seem to be less frequent. We have investigated the role of p53 mutations in tumorigenesis in British patients with HCC. The aim of this study was to determine the frequency and mutational spectrum of the p53 gene in HCCs from British patients. METHODS: DNA from 170 HCCs, of well-defined etiology, in British patients was analyzed by single-stranded conformational polymorphism using the polymerase chain reaction technique. Mutations were then characterized by direct sequencing. RESULTS: Twenty-nine percent of tumors had p53 mutations. Ten of 14 (71%) hemochromatotic cancers had mutations within the p53 gene, and clustering of these mutations at codon 220 (A-G) was found in 5 cases; 3 others had T-A mutations. No clustering was found in HCCs with other etiologies. CONCLUSIONS: p53 mutations are more common than was thought in Northern European HCCs. This is the first demonstration of p53 mutational clustering in HCCs from hemochromatotic subjects.
Aged↗
Hepatic angiomyolipoma: a clinicopathologic study of 30 cases and delineation of unusual morphologic variants.
Hepatic angiomyolipoma (AML) is frequently misdiagnosed. HMB-45 is a promising immunomarker for this tumor that leads to recognition of some AMLs with unusual morphology. The purpose of this collaborative study is to better define the morphologic variations of AML. Thirty AMLs were examined, including four biopsy specimens and two fine-needle aspirates. The diagnosis was confirmed by the presence of HMB-45-positive myoid cells. Almost half the cases were originally misdiagnosed as carcinomas or sarcomas. There was marked female predominance (25:5), and the mean age was 48.7 years (range 29-68). Three patients (10%) had evidence of tuberous sclerosis and all had renal AML. According to the line of differentiation and predominance of tissue components, the tumors was subcategorized into mixed, lipomatous (> or = 70% fat), myomatous (< or = 10% fat), and angiomatous type. The mixed type was the most common (11 resected cases), comprising sheets of epithelioid muscle cells admixed with islands of adipocytes, abnormal vessels, and frequently, hematopoietic cells. Six tumors (including three from biopsy specimens) were heavily fatty and showed predominantly adipocytes with epithelioid and short spindle myoid cells webbed between fat cells. Of 10 myomatous AMLs, five tumors showed a pure sinusoidal trabecular pattern and comprised mainly epithelioid cells. Typically, mature adipocytes were absent or scanty, but fat was seen as fine droplets within cytoplasm or as occasional large globules in sinusoids. Pelioid and inflammatory pseudotumor-like patterns were identified focally. Regarding cellular features of the myoid cells, most of the epithelioid cells were either eosinophilic or clear with spiderweb cell morphology. Three AMLs showed an almost purely oncocytic appearance with scanty fat. Large pleomorphic epithelioid cells existed as small foci. Spindle cells arranged in long fascicles were uncommon. D-PAS-positive globules were common around pelioid areas. Brown pigments with staining characteristics of hemosiderin and/or melanin were noted. In conclusion, we propose HMB-45-positive myoid cells as the defining criterion of hepatic AML, which is a tumor capable of dual myomatous and lipomatous differentiation and melanogenesis. Because of its protean morphologic appearance, recognition of the various variant patterns and cell types is important for a correct diagnosis, assisted by immunohistochemical confirmation with HMB-45. Trabecular and oncocytic cell tumors appear to stand out as distinctive subtypes.
Adult↗
Recurrence of primary biliary cirrhosis after transplantation. The pathologist's view.
There is now good evidence that primary biliary cirrhosis can recur after transplantation. The diagnosis rests on the liver histology which may be difficult to interpret in the setting of a grafted liver where specific markers are lacking. The triggering factor(s), rate of recurrence and the precise role of immunosuppression remain to be determined.
Diagnosis, Differential↗
A randomized study comparing ribavirin and interferon alfa monotherapy for hepatitis C recurrence after liver transplantation.
Hepatitis C virus (HCV) infection usually recurs after orthotopic liver transplantation (OLT), and most patients develop graft damage. This study compared the efficacy of interferon alfa (IFN-alpha) and ribavirin monotherapies in liver transplant recipients with chronic hepatitis C in the graft. Thirty OLT recipients with chronic hepatitis C were randomized to receive either IFN-alpha (3 MU three times a week) or ribavirin (up to 1.2 g daily) for 24 weeks. Virological, biochemical, and histological responses to treatment were assessed. Twenty-eight patients completed the treatment regimen, two ribavirin-treated patients being withdrawn because of severe hemolysis. Normalization of serum aspartate aminotransferase was achieved in 13 of 14 patients receiving ribavirin (93%) and 6 of 14 patients receiving IFN-alpha (43%; P=.01). Lobular inflammation was reduced in 9/14 ribavirin-treated (64%) and 3 of 14 IFN-alpha-treated patients (21%; P=.05), each of whom had a biochemical response. However, the total histological activity index did not improve in either the interferon (P=.43) or the ribavirin (P=.96) group. Posttreatment viremia levels were significantly reduced in IFN-alpha-treated (P=.05) but not in ribavirin-treated (P=.88) patients. Hemolysis occurred in all ribavirin-treated patients, with serum hemoglobin decreasing to < 10 g/dL in 50%. Total leukocyte and lymphocyte counts decreased significantly during ribavirin treatment (P=.02 and P=.004, respectively). We concluded that in patients with chronic hepatitis C after OLT, IFN-alpha retains an antiviral effect whereas ribavirin is superior in achieving normalization of serum aspartate aminotransferase levels and reducing lobular inflammation, but not the total histological activity index. These findings provide a rationale for combination therapy in the post-OLT setting, although patients must be carefully monitored for hemolysis.
Adult↗
Autoimmune hepatitis overlapping with primary sclerosing cholangitis in five cases.
OBJECTIVE: We report five cases (four male; median age 20 yr, range 14-38 yr) of an autoimmune hepatitis/primary sclerosing cholangitis overlap syndrome. The patients presented with jaundice, elevated serum aminotransferase and alkaline phosphatase activities, hyperglobulinemia with high immunoglobulin G (IgG) levels, circulating antinuclear and/or smooth muscle autoantibodies (> or = 1:40), and moderate to severe interface hepatitis on liver biopsy (with biliary features in four). METHODS: All five fulfilled criteria for diagnosis of "definite" autoimmune hepatitis and showed marked responses to prednisolone and azathioprine therapy, with relapses occurring during reduction or withdrawal of treatment. Cholangiographic features of primary sclerosing cholangitis were found in three patients at presentation and after intervals of 7 and 14 yr in the other two. Only two had evidence of inflammatory bowel disease. Diagnostic criteria for identifying those patients who may benefit from immunosuppressive therapy were reviewed. RESULTS: Review of the literature revealed only 11 similar cases that were sufficiently well described for comparison. However, in contrast to these and the present cases, preliminary data from other studies have suggested a marked association with ulcerative colitis and a poor response to immunosuppressive therapy. CONCLUSIONS: It is recommended that the possibility of an autoimmune hepatitis/primary sclerosing cholangitis overlap syndrome responsive to immunosuppressive therapy should be considered in any patient presenting with a hepatitic illness with hyperglobulinemia, antinuclear or smooth muscle autoantibodies, and biliary changes on liver biopsy. Cholangiography should be considered in such patients.
Adolescent↗
Use of extracorporeal liver assist device and auxiliary liver transplantation in fulminant hepatic failure.
The case history of a 14-year-old boy with fulminant hepatic failure secondary to non-A, non-B hepatitis who fulfilled selection criteria for orthotopic liver transplantation is described. Two forms of liver support were used (extracorporeal liver assist device and an auxiliary partial orthotopic liver transplantation) to provide additional time to allow spontaneous recovery to occur. During the 66 h of extracorporeal haemoperfusion through the device, haemodynamic stability was maintained along with improvements in serum bilirubin (555 to 381 mumol/l), and international normalized ratio (INR) (3.7 to 2.9). Deterioration in these parameters was observed following cessation of treatment and 10 h later, after a donor liver had become available, an auxiliary transplant was performed. Clinical recovery, though initially slow, was eventually complete, with histopathological and scintigraphic evidence of full liver regeneration at 3 months. Withdrawal of his immunosuppressive drugs began at 6 months and was complete by 14 months after auxiliary transplantation. He has since remained well with normal liver function tests. Temporary liver support may provide additional time for spontaneous recovery of the native liver to occur in selected cases of fulminant hepatic failure, even when criteria are fulfilled for orthotopic liver grafting.
Adolescent↗
Long-term outcome of hepatitis C infection after liver transplantation.
BACKGROUND: End-stage cirrhosis related to hepatitic C virus (HCV) is a common reason for liver transplantation, although viremia ia known to persist in most cases. We investigated the impact of persistent HCV infection after liver transplantation on patient and graft survival and the effects of the HCV genotype and the degree of HLA matching between donor and recipient on the severity of recurrent hepatitis. METHODS: A group of 149 patients with HCV infection who received liver transplants between January 1982 and April 1994 were followed for a median of 36 months; 623 patients without HCV infection who underwent liver transplantation for end-stage chronic liver disease were used as a control group. A total of 528 liver-biopsy specimens from the HCV-infected recipients were reviewed, including 82 obtained one year after transplantation as scheduled and 39 obtained at five years as scheduled. In addition, biopsy specimens were obtained from 91 of the HCV-negative patients five years after transplantation. RESULTS: Cumulative survival rates for the 149 patients with HCV infection were 79 percent after one year, 74 percent after three years, and 70 percent after five years, as compared with rates of 75 percent, 71 percent, and 69 percent, respectively, in the HCV-negative transplant recipients (P=0.12). Of the 130 patients with hepatitis C infection who survived more than 6 months after transplantation, 15 (12 percent) had no evidence of chronic hepatitis on their most recent liver biopsy (median followup, 20 months), 70 (54 percent) had mild chronic hepatitis (median, 35 months), 35 (27 percent) had moderate chronic hepatitis (median, 35 months), and 10 (8 percent) had cirrhosis (median, 51 months). Graft loss occurred after a median of 303 days in 27 of the 149 patients, including 5 with HCV-related cirrhosis and 3 with HCV-related cholestatic hepatitis. Infection with HCV genotype 1b was associated with more severe graft injury, whereas the primary immunosuppressive regimen used and the extent of HLA mismatching between donors and recipients had no significant effect on this variable. CONCLUSIONS: After liver transplantation for HCV-related cirrhosis, persistent HCV infection can cause severe graft damage, and such damage is more frequent in patients infected with HCV genotype 1b than with other genotypes. After five years, the rates of graft and overall survival are similar between patients with and those without HCV infection.
Adult↗
Abnormal intracellular distribution of O6-alkylguanine-DNA-alkyltransferase in hepatitis B cirrhotic human liver: a potential cofactor in the development of hepatocellular carcinoma.
The expression of O6-alkylguanine-DNA-alkyltransferase (ATase), which is responsible for repair of the promutagenic and cytotoxic DNA lesion O6-alkylguanine, was examined by immunostaining in a series of liver sections from normal and hepatitis-B cirrhosis patients using a polyclonal anti-human ATase antiserum. In 10 normal liver sections, the ATase staining was predominantly nuclear and very intense in the majority of the hepatocytes with a panacinar distribution. In contrast, in 15 hepatitis-B sections, the ATase was located mainly in the cytoplasm of the majority of the hepatocytes and had a perinuclear distribution. Scattered hepatocytes showed a more intense staining involving all or part of their cytoplasm; nuclear staining, however, was reduced in intensity, being inconspicuous in seven and patchy and weak in eight. ATase activity in extracts of 10 of the hepatitis-B livers varied from approximately 90 to 360 fmoles/mg protein and there was no apparent relationship between these levels and the cellular distribution of the enzyme. The sequestration of the ATase protein in the cytoplasm, away from its site of action in the cell nucleus suggests that in hepatitis-B cirrhosis, the repair of O6-alkylguanine lesions by ATase may be less efficient than in normal hepatocytes. The abnormal cellular distribution of ATase may thus be an additional cofactor in the development of hepatitis-B-associated hepatocellular carcinoma.
Adult↗
A longitudinal analysis of hepatitis C virus replication following liver transplantation.
BACKGROUND & AIMS: The pathogenesis of graft injury in liver transplant recipients with recurrent hepatitis C virus (HCV) infection remains poorly understood. In this study, the relationship between HCV replication, genotype, and the evolution of graft damage was investigated. METHODS: HCV RNA was quantified in 184 protocol sera from 25 patients transplanted for HCV cirrhosis. HCV isolates were genotyped, and hepatic expression of core and NS4 antigens was sought in protocol allograft biopsy specimens. RESULTS: Acute lobular hepatitis was accompanied by a steep increase in HCV RNA levels and the appearance of core and NS4 antigens in the graft. Methylprednisolone treatment for acute rejection led to a 4-100-fold increase in serum HCV RNA. At the end of follow-up, HCV RNA levels were 3-112 times pretransplant levels and were higher in patients with more severe hepatitis. Progressive liver damage developed in 7 of 14 patients with HCV genotype 1b and in 1 of 11 patients infected with other genotypes (P = 0.03). CONCLUSIONS: Peak viremia levels and the initial detection of HCV antigens in hepatocytes suggests increased viral replication at the time of acute HCV hepatitis in the graft. Genotype 1b and higher viremia levels were associated with more severe chronic graft damage.
Adult↗
Importance of concomitant viral infection during late acute liver allograft rejection.
We have determined accompanying events and reviewed the management and outcome of late acute cellular rejection episodes in 384 consecutive liver recipients. A significant proportion of patients experienced concomitant viral infection (group 1, n = 15 [41%]), with CMV infection comprising the largest group and smaller contributions from other viruses (CMV, 30%; HSV, 5%; EBV, 3%; varicella zoster virus, 3%). Thirteen (35%) patients (group 2) developed late rejection associated with low maintenance immunosuppression, and in a further 10 patients (group 3), no accompanying factor could be identified. Refractory rejection was higher in late compared with early rejection episodes in our series (29% vs. 9.2%, P < 0.05). Antiviral chemotherapy administered in rejection episodes with concomitant viral infection, either as sole treatment in cases with accompanying hepatitis or as adjunctive therapy to further supplemental immunosuppression in episodes of steroid-resistant rejection, controlled the rejection process in all treated patients.
Adolescent↗
Intrahepatic expression of hepatitis C virus antigens in chronic liver disease.
Localization of hepatitis C virus (HCV) antigens was studied in fresh frozen and formalin-fixed, paraffin-embedded liver tissue by immunoperoxidase using monoclonal antibodies to nucleocapsid protein and polyclonal human immunoglobulin G purified from plasma containing antibodies to structural and non-structural antigens of hepatitis C virus. The results observed using monoclonal antibody to HCV core were similar to those of polyclonal IgG against HCV antigens in the majority of cases and both correlated well with HCV status as defined by 'nested' polymerase chain reaction. HCV antigens were detected in both hepatocytes and mononuclear cells. Using polyclonal human IgG, a small proportion of biliary epithelial cells were also positive in 6/29 patients. In most of the specimens examined, relatively few cells (1-5 per cent) were found to be positive for HCV antigens. The cryostat sections, using polyclonal IgG against HCV antigens, exhibited greater immunohistochemical staining, suggesting that the fixation and processing of the tissue may be a major factor in the conservation and the outcome of HCV antigen(s) findings. However, the results using monoclonal antibodies may reflect the specificity of antigen expression.
Antibodies, Monoclonal↗