Case report

A 62 year old UK born Caucasian male and retired hospital porter, who had contracted HBV during his work, was referred in September 1997 because of hepatic encephalopathy, ascites, spontaneous bacterial peritonitis, and poor synthetic liver function. His serum was positive for hepatitis B surface antigen (HBsAg), HBeAg, HBV DNA, positive intermittently for IgM antibody to hepatitis B core antigen but negative for antibodies to hepatitis B e antigen (anti-HBe), anti-hepatitis D virus (HDV), and anti-hepatitis C virus. Liver biopsy confirmed cirrhosis with hepatitis B core antigen (HBcAg) staining of hepatocytes. The concentration of α fetoprotein was 46 IU/l (normal <10) but no focal lesion was seen on pretransplant imaging with ultrasound scan, computed tomography, or hepatic arteriography.

The patient underwent orthotopic liver transplantation without complications. Both donor and recipient were cytomegalovirus antibody negative. He was immunosuppressed initially with tacrolimus (target trough plasma level 5–15 μg/l), azathioprine (1 mg/kg), and prednisolone 20 mg daily. Examination of the liver explant confirmed HBV related cirrhosis without hepatoma. Immunohistochemistry showed extensive cytoplasmic staining for HBsAg while 5–10% of hepatocytes showed nuclear and occasional cytoplasmic HBcAg staining.

The patient received 5000 IU of HBIg perioperatively and this dose was repeated three times during the first week after transplantation. Antibody titre to hepatitis B surface antigen (anti-HBs) at day 10 post-transplant was 777 IU/l. Thereafter, HBIg infusions were repeated to sustain anti-HBs levels above 100 IU/l. On day 21 post-transplant, serum was negative for HBV DNA and anti-HBs titre was 174 IU/l.

By day 28 he had become positive for HBV DNA in serum while also positive for anti-HBs at a titre of 124 IU/l. At day 42 post-transplant, despite continued HBIg administration, the anti-HBs titre remained persistently below 100 IU/l. At this point HBV DNA, HBeAg, and HBsAg were detected in serum but anti-HBe and anti-HDV were not. Liver biopsy at day 56 (fig 1) showed minimal portal inflammation without fibrosis. Immunohistochemistry for both HBsAg and HBcAg was negative. He was commenced on lamivudine 100 mg.

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Figure 1

Liver biopsy on day 56 after transplantation, showing minimal portal inflammation without fibrosis.

At four months, liver biochemistry was normal apart from mildly raised alanine aminotransferase (ALT) at 61 IU/l (normal <55). HBV DNA, HBeAg, and HBsAg were present in serum. Anti-HBs titres remained <100 IU/l despite regular infusions of HBIg. Prednisolone was withdrawn while tacrolimus was continued to maintain a trough plasma level of 5–10 μg/l, and lamivudine was continued at 100 mg daily.

At 10 months, serum albumin, alkaline phosphatase, and bilirubin were in the normal range but serum ALT had risen to 149 IU/l. HBV DNA, HBeAg, and HBsAg were present in serum. Repeat liver biopsy (fig 2A) showed progression to stage 2 liver fibrosis. Immunohistochemistry demonstrated that 30% of hepatocytes had strong nuclear and also cytoplasmic staining for HBcAg (fig 2B) while 50% of hepatocytes stained positively for HBsAg (fig 2C). Azathioprine was withdrawn; tacrolimus, lamivudine, and HBIg were continued as before.

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Figure 2

(A) Liver biopsy at 10 months after transplantation showing progression to stage 2 fibrosis. (B, C) Liver immunohistochemistry 10 months post-transplant demonstrating that 30% of hepatocytes had strong nuclear and cytoplasmic staining for hepatitis B core antigen (B) while 50% of hepatocytes stained positively for hepatitis B surface antigen.

At 15 months, he became unwell and developed jaundice with pruritus requiring hospitalisation. Liver biochemistry revealed albumin 34 g/l, bilirubin 94 μmol/l (normal <17), alkaline phosphatase 171 IU/l (normal <130), and ALT 152 IU/l. Prothrombin time was 17 seconds (normal <16). HBV DNA, HBeAg, and HBsAg were present in serum. He was then demonstrated to have lamivudine resistant HBV infection.

Two groups of characteristic sequence mutations in the HBV polymerase gene are associated with lamivudine resistance17 and located in the reverse transcriptase (RT) domain of the protein, focused on the YMDD catalytic centre of the enzyme. In group I viruses the methionine residue at position 550 is substituted by valine; this change is associated with a second mutation of methionine for leucine at position 526. In group II viruses a mutation of the methionine 550 residue to isoleucine alone is responsible for resistance. Viral particles were isolated from serum and the region surrounding the RT active site domain was amplified using polymerase chain reaction. Fragments containing amino acids 347 to 690 were isolated and the sequence determined. The virus circulating in this patient showed the presence of the M550V and M526L combination.

Repeat biopsy (fig 3A) showed portal tract inflammation with occasional polymorphs, bile duct damage, and mild lobular lymphocytic and polymorphic infiltrate with feathery degeneration of hepatocytes. There was minor canalicular and cytoplasmic cholestasis but fibrous expansion of portal tracts with portal-portal linking fibrosis as well as isolation of small groups of hepatocytes by dissecting fibrous septae (fig 3B). Staining for HBsAg and HBcAg was positive, with the latter in both cytoplasm and nuclei. The overall appearances were characteristic of FCH.6

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Figure 3

(A, B) Liver biopsy at 15 months post-transplant showing fibrosing cholestatic hepatitis.

Adefovir dipivoxil was commenced at 10 mg daily while continuing lamivudine and HBIg as previously. Within two weeks he had made a remarkable recovery with resolution of all symptoms, and liver biochemistry and prothrombin time returned to normal (table1).

HBV DNA concentration (Roche PCR) in serum fell rapidly and progressively to undetectable at day 106 after commencing adefovir dipivoxil (the limit of detection of the assay is 400 copies/ml). By day 138 post-adefovir dipivoxil, HBeAg/anti-HBe seroconversion had occurred. Repeat liver biopsy at day 102 post-adefovir dipivoxil showed complete resolution of cholestasis, a marked decrease in inflammation, and regression of fibrosis (fig 4A). There was occasional widening of portal tracts by fibrosis (stage 2) but no evidence of portal-portal bridging as before. Immunohistochemistry was negative for HBsAg while HBcAg was found in occasional hepatocyte nuclei but not in cytoplasm (fig 4B).

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Figure 4

(A) Liver biopsy at day 102 after commencing adefovir dipivoxil 10 mg daily showing complete resolution of cholestasis, a marked decrease in inflammation, and regression of fibrosis (stage 2). (B) Liver immunohistochemistry at day 102 after commencing adefovir dipivoxil 10 mg daily demonstrating negative staining for hepatitis B surface antigen while hepatitis B core antigen was found in occasional hepatocyte nuclei but not in the cytoplasm.

HBIg was withdrawn after 12 months of combination therapy. He has not experienced any side effects due to adefovir dipivoxil and remains well after 16 months of continuous treatment with adefovir dipivoxil and lamivudine.

Discussion

We believe that this is the first report of a patient developing FCH while being treated with lamivudine. The response to treatment of lamivudine resistant FCH with adefovir dipivoxil was rapid and complete and sustained at 16 months.

The risk of graft infection with HBV after liver transplantation is greater in those patients with detectable HBV replication at the time of transplantation. In the mid-1990s, many centres excluded patients with HBeAg or HBV DNA in serum from liver transplantation because of the poor associated prognosis following graft infection with HBV. The Eurohep consensus document in 1994 recommended that such patients should only undergo transplantation in the context of a clinical trial.18 For those patients without detectable HBV replication at the time of transplantation, the risk of graft infection and death from HBV related graft disease is reduced by HBIg.19

The introduction of lamivudine has revolutionised the management of patients undergoing liver transplantation for HBV infection, especially those with detectable HBV replication at the time of operation. Lamivudine can reduce the risk of graft infection with HBV after liver transplantation3 ,4 while the combination of HBIg and lamivudine is even more effective.20 However, initial enthusiasm has been tempered by the recognition of evolving resistance to lamivudine with time, characterised by the YMDD mutations.5 Until now, the therapeutic options for managing lamivudine resistant HBV and related liver disease in the graft have been limited. A second transplant for HBV related graft failure carries a prohibitive HBV related mortality.21

Adefovir dipivoxil is an oral prodrug of adefovir whose active metabolite, adefovir diphosphate, inhibits viral polymerases at concentrations much lower than those needed to inhibit human DNA polymerases α, β, and γ.14 The intracellular half life of the active metabolite is approximately 30 hours, enabling once daily dosing. Adefovir dipivoxil has been shown to reduce HBV DNA levels by a median of 4.1 log₁₀ and induced seroconversion from HBeAg to anti-HBe in three of 15 (20%) patients who were treated for 12 weeks at 30 mg once daily.22 ,23 More importantly, adefovir dipivoxil has been shown to be effective in treating lamivudine resistant strains of hepatitis B14 ,15 and thus is an attractive option for patients with HBV graft infection, despite treatment with HBIg and lamivudine in combination.

A devastating form of cytopathic injury accompanies HBV infection in the graft, termed FCH,6 which untreated carries a mortality of 100%. The natural history of lamivudine resistant HBV infection in the graft and the speed of progress are less well documented but several deaths have now been reported.24Thus we believe that our patient had a very limited life expectancy. The introduction of adefovir dipivoxil was associated with rapid clinical, biochemical, virological, and histological remission. The persistence of HBV antigens in liver tissue, albeit at reduced quantities, despite control of HBV replication, reflects the fact that these agents do not eliminate HBV DNA from tissue and that transcription does continue. However, it is likely that infected hepatocytes will be eliminated with time and that HBV antigens would then be lost eventually. This assumes that there would be no loss of inhibition of HBV replication through failure of compliance or emerging resistance to the combination. To avoid resistance, maximal suppression of viral replication is desirable. Combination therapy of nucleotide analogues with HBIg provides maximal suppression. However, the long term toxicity of the nucleotide analogues remains unknown at present.

We have recently added adefovir dipivoxil to lamivudine in four further patients with lamivudine resistant HBV graft infection, with uniform success, although follow up is limited. Preliminary experience in five patients with more benign disease suggests that this combination is likely to be effective.25 In our patient described here, loss of HBV DNA from serum from such a high baseline level (by a decrease from baseline of >5.3 log₁₀) indicates the potency of the combination of lamivudine and adefovir dipivoxil, while seroconversion to anti-HBe is unique in our experience in this setting. Resistance to this combination has not yet been reported. Our experience with this combination may be a strong pointer to future therapy of HBV both within and outside the transplant setting.