Fatal Reactivation of Precore Mutant Hepatitis B Virus Associated with Fibrosing Cholestatic Hepatitis after Bone Marrow Transplantation

Case Report

A 49-year-old Chinese man had allogeneic bone marrow transplantation for acute myeloid leukemia. The patient had no history or clinical or biochemical evidence of liver disease. Before transplantation, the patient was positive for the hepatitis B surface antigen (HBsAg), negative for the hepatitis B e antigen (HBeAg), positive for the antibody to HBe (anti-HBe), positive for the antibody to hepatitis B core IgG (anti-HBc), and negative for the antibody to hepatitis B surface antigen (anti-HBs). Serology was unchanged throughout the course of therapy after transplantation. The human leukocyte antigen-identical donor was his healthy 43-year-old brother, whose only HBV marker was IgG anti-HBc. Hepatitis B virus could not be sequenced before transplantation because both donor and recipient were HBV-DNA-negative by polymerase chain reaction [7]. The patient received standard prophylaxis for graft-versus-host disease with methotrexate and cyclosporine. Hematologic remission was verified by bone marrow examinations on days 100 and 190. The hepatologic course is shown in Figure 1. Early complications included transient veno-occlusive disease and grade 2 graft-versus-host disease associated with modest elevation of liver test findings. Serum on day 55 was positive for HBV DNA by polymerase chain reaction.

View larger version:

• In this window
• In a new window

Figure 1. Panels above the graph show the time course of drug therapies. PCR = polymerase chain reaction. Hepatologic course after bone marrow transplantation, including alanine aminotransferase (ALT) levels and hepatitis B virus (HBV) DNA.

Successful treatment with ganciclovir for cytomegalovirus gastritis and pericarditis was initiated after day 94. On day 143, prednisone was given for recurrent jaundice and neutropenia. Liver function progressively deteriorated, and serum HBV DNA increased. Examination of liver histologic findings on day 171 showed early fibrosing cholestatic hepatitis with severe swelling of hepatocytes, apoptotic bodies, intense hepatocyte immunohistochemical staining for hepatitis B core antigen (HBcAg) and HBsAg but little inflammation (Figure 2). On day 173, therapy with cyclosporine was stopped, and therapy with ganciclovir, 5 mg/kg daily, and foscarnet, 5.4 g daily, was initiated [5]. Liver failure progressed, and the patient died on day 198. Autopsy was refused. Hepatitis B virus DNA from serum was amplified by polymerase chain reaction for direct sequencing (Applied Biosystems, Scoresby, Victoria, Australia) of the precore region. The precore mutant HBV (guanosine to adenosine substitution at nucleotide 1896) was present throughout the course of therapy after transplantation.

View larger version:

• In this window
• In a new window

Figure 2. Hepatocytes show variable cytoplasmic staining for surface antigen and intense nuclear and cytoplasmic staining for core antigen. The amount of surface antigen is greatest in severely altered hepatocytes (original magnification, × 330). Immunohistochemical stains for hepatitis B surface antigens (top) and core antigens (bottom) on day 171.

Discussion

Severe reactivation of hepatitis B in HBsAg-positive persons after bone marrow transplantation is infrequent and unpredictable [1-3, 8, 9]. Of 1980 patients who had bone marrow transplantation surveyed in the published series, 38 were HBsAg-positive before transplantation. Hepatitis B e antigen was present in the three reported cases of fatal reactivation (two HBsAg-positive patients, one anti-HBs-positive and anti-HBc-positive patient) [1-3]. In our patient, reactivation was not detected by standard serologic testing; HBeAg did not reappear, and anti-HBc IgM was not present. This is the phenotype of precore mutant HBV. The mutation in the precore region creates a translational stop codon, which results in failure to secrete HBeAg. This serologic finding is described in a report of three cases of fulminant hepatic failure from precore mutant HBV after cytotoxic chemotherapy [4]. It is clear from the literature and from our case that HBV DNA must be measured to detect reactivation of precore mutant HBV. Earlier detection is reported to facilitate successful antiviral treatment after liver transplantation [5].

Donor serology is important for the outcome. In the published series, 8 of 38 HBsAg-positive patients lost HBsAg, and 3 patients seroconverted to anti-HBs [1-3, 8, 9]. In the latter cases, the donors were anti-HBs-positive. Adoptive transfer of immunity to HBV is well documented [10]. Vaccination of our patient's donor (who was anti-HBc-positive) before bone marrow harvest may have evoked anti-HBs and resulted in the elimination of HBV by the graft.

To our knowledge, this is the first report of fibrosing cholestatic hepatitis after bone marrow transplantation. In immunocompetent hosts, hepatitis B-induced liver disease is caused by an immune system attack on infected hepatocytes. Fibrosing cholestatic hepatitis, a distinct and usually fatal form of hepatitis B-associated liver injury, is described in patients receiving immunosuppressive therapy after liver transplantation. Hepatocytes accumulate large amounts of HBsAg and HBcAg, which appear to be cytopathic [6]. Because the precore mutant is unable to secrete HBeAg from the liver cell, we propose that it plays a role in the accumulation of HBV antigens in fibrosing cholestatic hepatitis.

Our patient showed the unique combination of fatal reactivation of precore mutant HBV after bone marrow transplantation and fibrosing cholestatic hepatitis. This case highlights the need to detect HBV precore mutant reactivation after bone marrow transplantation and the need for earlier antiviral treatment.